MAÍS Southwest Project – dedicated to Deb Muenchrath

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MAÍS Southwest Project – dedicated to Deb Muenchrath
MAÍS (Maize of American Indigenous Societies) Southwest:
Ear Descriptions and Traits that Distinguish 27 Morphologically
Distinct Groups of 123 Historic USDA Maize (Zea mays L. spp. mays)
Accessions and Data Relevant to Archaeological Subsistence Models
Karen R. Adams (Crow Canyon Archaeological Center)
Cathryn M. Meegan (Arizona State University)
Scott G. Ortman (Crow Canyon Archaeological Center)
R. Emerson Howell (University of Arizona)
Lindsay C. Werth (Iowa State University)
Deborah A. Muenchrath (Iowa State University)
Michael K. O’Neill (NMSU Agricultural Science Center)
Candice A.C. Gardner (USDA-ARS North Central Regional
Plant Introduction Station and Iowa State University)
January 2006
Support from the James S. McDonnell Foundation, JSMF Grant # 21002035
21st Century Research Award/Studying Complex Systems
Arizona State University
© 2006
Dedication
This research report is dedicated to team member Deborah A. Muenchrath, whose vision
has become reality. Deb provided the initiative, drive, and field protocols for an ambitious
project to systematically grow-out a large sample of historical southwestern U. S. and northern
Mexico Native American maize accessions to provide the basis for thorough descriptions of
developmental and morphological traits. The research reported here represents one of many
potential applications of this larger project. We are all deeply grateful for Deb’s guidance,
knowledge, and sense of humor in the field.
For questions, comments, or to obtain a copy of this report, contact Karen R. Adams,
[email protected]
i
Table of Contents
Introduction
Maize history
Status of Southwest maize landrace history
Landrace integrity
Ancient maize landraces: problems in recognition
Few existing Southwest Native American maize descriptions
Maize described elsewhere
Value of historic maize baseline
1
1
2
3
3
4
4
4
This Study
Agronomic objectives
Archaeological objectives
Grain yield estimates for archaeological subsistence models
Temperature parameters for archaeological subsistence models
Maize day-length sensitivity/insensitivity
Interplay of heat units and day-length
4
4
5
6
7
8
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Materials and Methods
Research location(s)
Archaeological accessions
Planting
Field observations
Daily weather and other records
The potential effects of cross-pollination
Agronomic harvest
Archaeological harvest
Maize drying
Maize ear analysis
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9
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12
12
12
13
13
16
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Results
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22
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22
26
27
27
28
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Field data
Weather data
Growing season length
CGDD units
Irrigation and fertilizer applications
Maize data recorded during the growing season
Planting and seedling emergence date(s)
Flowering date(s)
Maturity dates
Plant height(s)
The archaeological harvest
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Table of Contents (cont.)
Analysis results
Estimated kernel weight per maize ear
Maize morphological groups
Field observations
Ear characters
Kernel traits
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29
30
31
34
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Discussion
Geographical/cultural distribution of alpha groups
Shared maize
Population genetic analyses
Implications for archaeological subsistence model
Temperature parameters important to maize maturity
CGDD units
Maize grain yields
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45
45
47
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Summary
53
Acknowledgements
57
References Cited
61
Appendix 1: Field observations on 123 Native American maize accessions
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Appendix 2: Ear characters of 123 Native American maize accessions
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Appendix 3: Kernel traits of 123 Native American maize accessions
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Figures and Tables
Figures
Figure 1: Location of project
Figure 2: General distribution of ethnographic groups included in this study
Figure 3: 2004 Farmington, NM maize experiment
Figure 4: Examples of kernel colors
Figure 5: Examples of sweet and flour endosperm
Figure 6: Examples of flint, pop, and dent kernel endosperm
Figure 7: Examples of unusual kernel or ear traits
Figure 8: Daily (DGDD) and cumulative (CGDD) growing degree days
through the 2004 growing season
Figure 9: Regression analysis results to predict kernel weight from ear weight
Figure 10: Principal component analysis of 123 maize accessions
Figure 11: Representative ears of alpha group 1
Figure 12: Representative ears of alpha group 2
Figure 13: Representative ears of alpha group 3
Figure 14: Representative ears of alpha group 4
Figure 15: Interdisciplinary MAÍS Southwest project personnel
Tables
Table 1: Native American maize accessions examined for this project
Table 2: Traits recorded on all ears
Table 3: Traits recorded on a sub-set of ears
Table 4: Monthly weather data
Table 5: Monthly applications of irrigation water and nitrogen fertilizer
Table 6: Morphological alpha-beta groups
Table 7: Discriminant analysis classification of alpha groups
Table 8: Field observations, alpha groups
Table 9: Field observations, beta groups
Table 10: Ear characters, alpha groups
Table 11: Ear characters, beta groups
Table 12: Kernel traits, alpha groups
Table 13: Kernel traits, beta groups
Table 14: Alpha group 4 ear characters and kernel traits compared to
modern hybrid dent maize
Table 15: Mean frost-free days and CGDD units for geographic/cultural groups
Table 16: Mean estimated kernel weight per ear and per plant, and mean
row number for alpha groups and geographic/cultural subgroups
Table 17: Summary of maize grain yields reported for three separate
experimental studies
Table 18: Number of estimated people fed by a hectare of maize plants
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10
15
18
19
20
25
26
29
32
38
38
39
39
60
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17
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27
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INTRODUCTION
Maize history. Among the most significant of developments during human history has been
the emergence of agricultural economies based on domesticated plants and animals. On many
continents, increasing reliance on domesticated resources provided subsistence security and the
possibility for surplus production, which then encouraged larger populations, the formation of
sedentary communities, and the evolution of complex societies. Complex societies, in turn, could
focus on developing technologies, political organization, art, and other fundamental aspects of
society.
One outstanding New World example of a successful plant domesticate has been the origin
and rapid spread of open-pollinated indigenous maize or corn (Zea mays L. ssp. mays), a member
of the grass (Poaceae) family. The maize success story is due in part to a relatively high grain
yield, in which a single planted kernel may grow into a plant with multiple ears, with each ear
capable of producing a minimum of a few hundred kernels. In addition, the genetic plasticity of
maize has enabled it to move into a wide range of environmental niches the world over.
Based on molecular evidence, maize may have diverged from a wild grass known as teosinte
(Zea mays L. ssp. parviglumis Iltis and Doebley var. parviglumis) somewhere in the Rio Balsas
lowlands in Guerrero, Mexico (Doebley et al. 1987) at approximately 9,000 years ago.
(Matsuoka et al. 2002b) Within 500 km of this area, the oldest presently known maize cobs are
from Guilá Naquitz Cave in Oaxaca, Mexico, directly dated to approximately 6,300 years ago.
(Benz 2001; Piperno and Flannery 2001) The subsequent spread of maize agriculture
differentially affected New World groups as it rapidly moved southward into South America and
northward into northern Mexico and the southwestern United States. For some groups or regions
in the United States, maize comprised a major component of subsistence soon after its arrival,
but for others a multi-century lag occurred before maize became a major dietary component.
Once Christopher Columbus took maize to the Old World in the 15th century, the impact of its
introduction there has also been significant.
In the southwestern U. S., a few radiocarbon dates document maize in both southern
Arizona (Freeman 1997)and in the Fence Lake region of west-central New Mexico (Huber 2005)
by more than 4,000 years ago. Maize parts directly dated to more than 3,300 years old have been
identified from numerous additional sites in Arizona, (Gilpin 1994; Huckell et al. 2001; Lascaux
and Hesse 2002; Mabry 2001; Mabry 2004a; Smiley 1994) New Mexico (Wills 1988), and
1
northern Chihuahua. (Roney and Hard 2002). Early irrigation canals date to between 3,000 and
2,400 years ago in both the Tucson Basin (Ezzo and Deaver 1998; Mabry 2004b) and the
uplands of northwestern New Mexico (Damp et al. 2002; Damp et al. 2000). Although the
presence of maize is now well-established, researchers continue to discuss the routes of maize
transmission/dispersal, and its initial role in subsistence economies (Berry 1985; Ford 1981; Ford
1985; Gregory and Diehl 2002; Huckell et al. 2002; Mabry 2004b; Matson 1991; Minnis 1992;
Smiley 1994; Vierra 2004; Wills 1988).
Status of Southwest maize landrace history. Despite what is documented about early
maize, very little is known: (a) about the specific maize type(s) or landraces that first entered the
Southwest (here and throughout, “Southwest” refers to the Greater Southwest, which includes
Arizona and New Mexico, portions of Colorado and Utah, and the northern Mexican states of
Sonora and Chihuahua); (b) about subsequent entries of additional maize germplasm into this
region; or (c) about how local landraces developed or were lost over time. For the purpose of this
paper, the term “landrace” (similar to a “cultivated variety” or cultivar) is used to describe maize
with specific growth, vegetative and reproductive traits, and environmental tolerances that allow
it to be distinguished from other maize landraces. A maize landrace develops locally or
regionally as: (a) it is grown in and adapts to a geographical/ecological region over time; and (b)
as farmers continuously apply selection pressure to it by choosing to plant selected kernels that
match their mental template(s) of an ideal maize type (ideotype). A kernel of maize is technically
a grass family fruit or caryopsis (with the seed inside), and commonly termed a “grain” or
“seed”.
Landraces can be distinguished from one another on the basis of many traits. Among
these are: (a) rates/timing of plant growth and development; (b) plant phenotypic traits (plant
height, size of stalks and leaves, etc.); (c) ear size, shape, and number of kernel rows; (d) kernel
color, endosperm type, and spacing between kernel rows; (e) average kernel (grain) yield per ear
or per plant; (f) moisture and temperature requirements, such as number of frost-free days and
accumulated growing season heat units needed to produce mature ears; and (g) day length
sensitivity/insensitivity. Traits related to taste, ease of grinding, dependability, and
religious/ceremonial requirements may also be important to indigenous conceptions of maize
landraces.
2
Landrace integrity. As a wind-pollinated plant, farmers who grow a number of different
maize landraces must plant them in separate fields, to keep them from cross-pollinating and thus
mixing the germplasm. It is reasonable to assume that the “integrity” of landraces, that is the
ability to grow and maintain them as distinct, varies through time and across space. Conservative
and traditional farmers are perhaps most likely to maintain distinct maize traits, resulting in
conservation of landraces. Conversely, other farmers perceive the variability resulting from
maize cross-pollination as opportunities to develop new landraces. Historically in Tepoztlan,
conservative communities practicing older customs grew the most uniform maize, other
agriculturalists grew less uniform maize, and urbanized groups removed from their traditional
way of life grew the most variable maize crops of all (Anderson 1972: 452). Finally, historical
events may occur that lead to maize landrace loss.
Maize kernel color may be a trait critical to maintaining landrace integrity. Because genes
often travel together in clusters, color may well transmit a range of information relevant to
agriculture, as if modern bar-codes had been attached to the ears. In northwestern Mexico
farmers use the color of kernels as an indicator of ecological, dietary, and medicinal traits of
maize. (Hernández Xolocotzi 1985: 425) There, kernel color guides the choices of where to
plant, when to plant, and for what the maize will be used
Ancient maize landraces: problems in recognition. Efforts to identify ancient maize
landraces have been hampered for a number of reasons. First, archaeological maize specimens
are most often limited to fragmented and burned parts of the ear (Adams 1994) and, as such,
carry information on only a small number of the entire suite of developmental and phenotypic
traits, as well as environmental preferences, that together define a landrace. Second, the role of
the environment (specifically variability in moisture received during the growing season) has
been experimentally demonstrated to have had notable effects on growth and reproductive
parameters of Tohono O’odham (Papago) flour maize, (Muenchrath 1995) as well as on the
morphology of its ears, cobs, and kernels (Adams et al. 1999). Similar studies that document the
effects of temperature variability on maize parts during the growing season have yet to be
accomplished. Third, as reported in ethnographic studies and inferred archaeologically, maize
cobs have been regularly used as a fuel or tinder source (Adams 1994). When maize cobs burn
they shrink to a variable and sometimes significant extent (Brugge 1965; Stewart and Robertson
3
III 1971). Simple experiments suggest shrinkage percentages appear linked to the length of time
the cobs are exposed to fire (Hildebrand 1994).
Few existing Southwest Native American maize descriptions. Perhaps one of the
biggest hurdles to assessing how many maize landraces first entered the Southwest over 4,000
years ago, and to documenting the subsequent introduction, movement, and distribution of
additional landraces through time, is the lack of a comparative historic descriptive maize
baseline. It seems surprising that in the 21st century, few well-documented descriptions exist for
the majority of historic Southwestern Native American maize landraces. Those described are
Zuni blue flour maize (Muenchrath et al. 2002) and Tohono O’odham white flour maize (Adams
et al. 1999; Muenchrath 1995).
Maize described elsewhere. Long ago, many New World countries/regions described
their indigenous maize in enough detail to be useful. The following countries or regions have all
reported on their historic “Races of Maize”: Bolivia (Ramírez et al. 1960), Brazil (Brieger et al.
1958), Central America (Wellhausen et al. 1957), Chile (Timothy et al. 1961), Columbia
(Roberts et al. 1957), Cuba (Hatheway 1957), Ecuador (Timothy et al. 1963), Mexico
(Wellhausen et al. 1952), Peru (Grobman et al. 1961), the West Indies (Brown 1960), and
Venezuela (Grant et al. 1963). Even Romania (Cristea 1987) has a similar document.
Value of a historic maize baseline. Having a solid descriptive indigenous maize
baseline is an important first step in: (a) reconstructing the first landrace(s) to enter the
Southwest; (b) recognizing the appearance of new landraces (either due to new germplasm
entering from Mexico or to on-going in-place adaptation of maize to regional settings and farmer
selection pressures); and (c) noting when ancient landraces may have been lost from the record.
Such a historic maize baseline must clearly describe a cross-section of the existing diversity of
Southwestern Native American maize landraces, and reveal the nature and extent of any
overlapping traits. Via comparisons of modern indigenous landraces with maize at various
temporal and geographic points in the past, it may then be possible to assess Native American
maize landrace conservation, addition, and loss over the last four millennia in the Southwest.
THIS STUDY
Agronomic objectives. Controlled grow-outs of 155 USDA maize accessions have been
undertaken by agronomists from Iowa State University (Deborah Muenchrath, Lindsay Werth)
4
and the USDA Plant Introduction Station in Ames, Iowa (Candice Gardner). The majority of
these accessions represent Native American indigenous open-pollinated maize collected from
Native American farmers by the U.S. Department of Agriculture in the second half of the 20th
century, and refreshed from time to time by the USDA. These accessions are considered to
represent a snapshot of maize variability in the relatively recent historic period, and it is hoped
that a fair cross section of this diversity is present.
The maize accessions have been grown-out in two sites. These include the New Mexico
State University Agricultural Science Center (Mick O’Neill) fields south of Farmington, New
Mexico (Figure 1) for both 2004 and 2005, and USDA Plant Introduction Station fields in Ames,
Iowa for 2004 only. The full 2-year experiment to describe maize developmental, vegetative, and
reproductive traits, along with well-documented environmental parameters, soil analyses, and
kernel protein analyses, will be reported as an Iowa State University Department of Agronomy
Master’s Thesis (Lindsay Werth). Agronomists associated with the North Central USDA Plant
Introduction Station and Iowa State University also plan to conduct genetic marker analyses to
help define the landraces.
Archaeological objectives. Archaeologists (Adams, Meegan, Ortman, and Howell) have
planned a three phase project, based on 123 accessions grown in Farmington in 2004. The Phase
1 goal (this report) has been to adequately describe and report metric and non-metric maize ear
characters and kernel traits, based on multiple observations. These data then help define a
number of distinctive morphological groups present in this collection of 123 accessions. In
addition, field traits (e.g. days from planting to ear maturity and from seedling emergence to ear
maturity), temperature parameters, and grain yield estimates relevant to archaeological
subsistence models based on maize are reported.
In Phases 2 and 3, archaeological research will focus on a number of maize ear, cob, and
kernel traits regularly recorded on ancient maize fragments by archaeobotanists (e.g. cupule
width, length, depth, and wing width; rachis segment length; rachis diameter; kernel length,
width, thickness; cob length; cob diameter; etc.). In Phase 2 these traits will be examined on
representative maize samples from each morphological group defined in Phase 1, to determine
which of these traits best distinguish among the broadly defined groups. Phase 3 will focus on
controlled burning experiments to assess the effects of charring on those diagnostic traits defined
in Phase 2. It is possible that ratios of traits will become more useful than actual measurements
5
affected notably when burned. By identifying which traits are diagnostic even when burned,
future archaeobotanical analysis efforts can be considerably focused.
Figure 1. Location of project. New Mexico State University Agricultural Science
Center, southwest of Farmington, New Mexico.
Grain yield estimates for archaeological subsistence models. Maize requires water and
nutrients throughout growth and development in order to produce maximum grain yield
(Kisselbach 1949). The plant’s potential to produce under particular environmental conditions is
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a function of its genetic potential. The rate of development is influenced by temperature,
available nutrients, and moisture stresses. Some stages of development are particularly critical:
seedling emergence, the weeks surrounding anthesis (pollen shed) and silking, and the period
during which the grains are filling. Severe stress during initial formation of reproductive
structures can reduce yield potential by reducing the number of spikelet pairs which develop into
rows of kernels or the number of ovules/row, which reduces kernel number per row.
Temperature influences pollen dispersal and viability, as well as stigmatic receptiveness and
pollen tube development. Moisture and nutrient deficiencies during the 4-week silking period
may further reduce the size of ears and number of kernels by delaying silking beyond anthesis, or
by reducing pollen viability or silk receptivity. Stress when kernels are maturing may reduce
yield by reducing kernel weight or causing kernel abortion.
One important outcome of this project will be to provide grain yield estimates per ear and
per plant of a range of Southwestern maize accessions all grown in an optimal, identical
environment that serves as a proxy for irrigation agriculture. For modeling ancient maize
productivity, archaeologists will benefit by having yield data on Native American maize
accessions relevant to their region(s) of interest. Currently, experimentally controlled yield
estimates of Native American maize are available only for Tohono O’odham flour maize (Adams
et al. 1999; Muenchrath 1995) and for Zuni blue flour maize (Muenchrath et al. 2002). General
grain yield estimates have also been reported by historic Hopi farmers (Bradfield 1971;
Manolescu 1995) and by non-Native American farmers growing hybrid dent maize with
increasingly improving technology (Burns 1983; Van West 1994).
Although yield estimates reported here will be useful for efforts to model maize grain
yield in the past, precipitation records for archaeological time periods are not yet available on a
monthly, or even a seasonal, basis. In addition, paleoenvironmental temperature reconstructions
are fairly generalized over broad regions. Finally, because this experiment offers a view of maize
performance under irrigation, use of resulting grain yield data for archaeological subsistence
models should be adjusted downward from this experimentally optimal situation to better
approximate average returns by ancient subsistence farmers dependent on natural precipitation.
Temperature parameters for archaeological subsistence models. Another trait useful
for archaeological subsistence models is the length of the growing season required to produce
mature ears. However the issue is more complicated than simply calculating the average number
7
of frost-free days in a given location. Rate of development and time to maturity are functionally
related to the accumulation of heat units, with cooler temperatures inhibiting and warmer
temperatures hastening growth and development, given adequate moisture and nutrition
(Muenchrath et al. 2002:20). Sufficient environmental heat is required to support enzymatic
processes related to growth and development, including adequate anther extrusion and pollen
shed (anthesis), silking, fertilization, starch synthesis, and kernel maturation. Maturity is
genetically controlled but influenced by environment. In a hot growing season with adequate
moisture, maturity will be achieved earlier than in a season with the same moisture, but limiting
cooler temperatures. Some of this variability is expressed in the range of days to maturity (95 to
130) reported for Zuni blue flour maize (Muenchrath et al. 2002: 20) and days required (115 to
130) for Hopi maize (Bradfield 1971). To date, the number of heat units required by different
Native American maize accessions to attain maturity has not been scientifically documented.
Maize day-length sensitivity/insensitivity. Native American maize accessions may have
different sensitivities to day length. Maize is generally considered a facultative short-day species
(basically requiring shorter days and longer nights to initiate certain physiological stages of
development toward maturity). Such sensitivity has been reduced in modern maize hybrids to
increase the geographic extent where they can be grown. At present, little is known about the
degree of day length sensitivity/insensitivity of Native American maize accessions.
Interplay of heat units and day-length. Germplasm adapted to warm environments
such as southern Arizona may be able to better withstand heat and may be more responsive to
day length due to modifying gene action. Thus, the Tohono O’odham “60 day maize”, requiring
only 60 days from planting to flowering (Muenchrath 1995), rapidly hastens to develop mature
ears in the oppressive heat of the Sonoran Desert, its area of adaptation. This allows maize to be
“double-cropped” in southern Arizona, planted first in March and then again later in July. The
March planting is clearly exposed to increasing day length, and would not advance toward
maturity if the plants indeed required short days. For this maize, day-length sensitivity may have
been altered as it was selected by native peoples to withstand a variety of growing season heat
conditions. At the present time, the first (March) planting matures during the hot months of May
and June, and the second (July) planting matures in the hot weeks following the start of summer
monsoon rains.
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In contrast, the Colorado Plateau has longer days prior to the solstice, is higher in
elevation, and has cooler nights. Maize grown here would have a better chance of maturing ears
if the shortening post-solstice days (lengthening nights) signaling the increasing likelihood of
frost also trigger the changes that hasten physiological maturity. When some maize brought from
farther south in Mexico is planted in the Southwest, it continues vegetative growth indefinitely,
and by the time the days become short enough to initiate reproduction, the growing season has
nearly ended. This suggests some Mexican accessions may also be day-length sensitive. The
current study centered in northern New Mexico may provide data relevant to these issues for
some of the accessions.
MATERIALS AND METHODS
Research location(s). The Farmington field site (36o 41’ N, 108o 18’ W) is approximately
seven miles southwest of Farmington, New Mexico. At an elevation of 5,640 feet, this Colorado
Plateau location annually receives an average of 8.2 inches of precipitation, and has 162 frostfree days from early May to mid-October (Smeal et al. 2006). Snows in the winter, generally
brought by storms originating to the north, are infrequent with snow depths generally less than 6
inches. Summer rains in the form of monsoonal storms during July-October bring precipitation
into the region from the Gulf of Mexico. Information about the Ames, Iowa, field site will be
reported by Lindsay Werth.
Archaeological accessions. The 123 accessions of interest to archaeologists from the 2004
Farmington field trials represent geographically and culturally diverse groups (Figure 2). These
include: Pueblo groups living along the Rio Grande River; Western Pueblo groups; southern
Arizona Tohono O’odham (Papago) and Akimel O’odham (Pima) groups; Northern Mexican
groups; groups living along the Lower Colorado River; and historically mobile groups such as
the Apache and Navajo (Table 1). Thirty-two of the original 155 accessions were eliminated as
duplicates, poorly documented, out of the Southwestern region, or clearly labeled Midwestern
hybrid dents. Information accompanying the original maize accessions is available via a webbased database titled “U.S.D.A. Agricultural Research Service, Germplasm Resources
Information Network (GRIN)”, located at http://www.ars-grin.gov/npgs/. Data stored in GRIN
for each accession includes the tribe or location of collection, and at times indigenous names
and/or information on the uses of the maize. For all accessions analyzed and discussed here, the
9
ACP (accessing institution identifier) and Accession number are reported in Appendix 1, along
with field observations.
Figure 2. General distribution of ethnographic groups included in this study. Project
located at the New Mexico State University Agricultural Science Center southwest of
Farmington, New Mexico.
10
Table 1. Native American maize accessions examined for this project.
Sub-group
No. of
Group
Region
Accessions
Rio Grande Pueblos Cochiti Pueblo
3
Isleta Pueblo
3
Jemez Pueblo
3
Picuris Pueblo
2
San Felipe Pueblo
2
Santa Clara Pueblo
1
Santo Domingo Pueblo
3
Siles (?) Pueblo
1
Taos Pueblo
2
Tesuque Pueblo
3
Unknown Pueblo
1
Zia Pueblo
4
Western Pueblos
Acoma Pueblo
4
Hopi Pueblos
32
Hopi Pueblo
Bacabi
1
Hopi Pueblo
Hotevilla
3
Hopi Pueblo
Moencopi
4
Laguna Pueblo
2
Mesita Pueblo
3
Zuni Pueblo
1
Southern Arizona
Papago (Tohono O’odham)
8
groups
Akimel O’odham/Tohono
5
O’odham (Pima/Papago)
Northern Mexican
Mexico
Chihuahua
4
groups
Mexico
Coahuila
1
Mexico
Sinaloa
1
Mexico
Sonora
4
Lower Colorado
Havasupai
5
River groups
Mojave
3
Walapai
1
Formerly mobile
Apache
2
groups
Navajo
11
Total, all accessions =
123
11
Planting. In the Farmington field (Figure 3a), agronomists laid out three separate replicated
blocks (Replicates 1, 2 and 3), and planted every accession once within each replicate. The
accession planting order was randomized between the replicates, to reduce potential influence of
specific neighboring accessions and to reduce any effects due to placement within the replicates
(e.g. edge effects). Thirty-five (or forty-five, in the case of poor germination) kernels of each
accession were planted on May 13 and 14 at a depth of 2 inches in single-row 20-foot long plots
(Figure 3b). Twelve plots were planted end to end in the field, separated by five feet (alley
length). Rows were spaced 68 inches apart. Three replicates were planted, separated by 136
inches.
Had the soil held moisture from winter precipitation, germination would have initiated
immediately following planting. However, the kernels were planted into dry soil, and could not
begin to imbibe moisture and germinate until after the fields were first irrigated on May 21st,
considered here the “effective” planting date. Following seedling emergence, 10 plants were
tagged within each plot for future observations (Figure 3c).
Field observations. After emergence, the seedlings were thinned to 19 plants per 20-foot
single-row plot, equivalent to 5,928 ppa (plants per acre) or 14,642 pha (plants per hectare).
Field growth and development data were subsequently gathered on ten randomly chosen plants
per row, with the exception of emergence dates, which were recorded on a per row basis. Time
consuming observations on tassels and ear plant traits were recorded on six plants per row at
flowering (Figure 3d). Although some rodent damage was experienced in 2004, the maize
appeared remarkably healthy and insect free. Regular weeding of the replicates was required,
given the wide row spacing, low plant density, and resulting lack of shading. Physiological
maturity was determined by longitudinally slicing an excised grain and recording the date of
black layer formation, signaling the end of kernel growth and development (Ritchie et al. 1997).
Daily weather and other records. Daily weather records recorded by the New Mexico
Climate Center within 0.25 miles of the experimental fields provide climatic data during the
May-October growing season. Air temperature records allow calculation of cumulating growing
season heat units (Cumulative Growing Degree Day, abbreviated CGDD) from date(s) of
planting to the date(s) when kernels of each accession reach physiological maturity. By that time,
accumulation of dry matter has reached maximum level, and maize will not be hurt by frost
12
(Ritchie et al. 1997). NMSU Agricultural Science Center staff also kept records of daily
precipitation, as well as of regular applications of irrigation water and fertilizer.
The potential effects of cross-pollination. For the purposes of this research, the potential
cross-pollination effects of close accession spacing will not affect the majority of maize
developmental and morphological traits. The observed kernel traits are a result of the genetics of
the accession and the pollen parent, potentially from a neighboring accession, so any effort to
plant these kernels would likely result in highly mixed fields of maize. However, the majority of
traits documented are maternally pre-determined by the genetic composition of the mother plants
that grew from the kernels provided by the USDA. In other words, growth traits, vegetative
morphology, timing of tasseling and silking, and most of the ear traits (general size, shape, row
number, etc.) are characteristic of the germplasm planted.
One exception to this is kernel color, which can derive from more than one source
(Weatherwax 1954). These sources include: (a) an outer pericarp layer (maternal); (b) an
aleurone layer beneath the pericarp (half paternal, half maternal); and/or (c) the endosperm (1
part paternal, 2 parts maternal). Some colors (blues/reds) are genetically quite complex, and
others (whites/yellows) are simpler (Kisselbach 1949). The system of recording color, explained
below, noted the main kernel color of each ear, as well as any significant secondary color.
Random kernels of different colors on an ear may indeed have resulted from cross-pollination
effects of neighboring accessions, but if these colors did not achieve significant representation,
they were not noted. Comparisons between remaining seed stock of original kernels against the
colors of the kernels from the field trials revealed that the main kernel colors from the 2004
grow-outs closely matched the original USDA accessions. The fact that some of the accessions
pollinated in succession (temporal isolation), rather than simultaneously, reduced influence of
accession cross-pollination on kernel color(s) to some extent, particularly for early and late
flowering accessions. Full anthesis and silking data will be reported by Lindsay Werth.
Agronomic harvest. Agronomists harvested maize from all three replicates October 17-19.
On five plants of each accession they collected the primary maize ear, which is the uppermost
(and often the largest) ear on the main stalk, along with ear observations. Data collected on the
2004 agronomic harvest of approximately 2,350 ears will be reported by Lindsay Werth.
13
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14
Figure 3a: General view of the maize
replicates in the distance.
Figure 3b: All accessions were planted in
separate plots within long rows.
Figure 3c: Plastic tags were placed at the
base of 10 plants within each plot.
Figure 3d: Growth and developmental
observations were made continuously
throughout the long growing season.
Figure 3: 2004 Farmington, New Mexico maize experiment
15
Archaeological harvest. The 2004 archaeological harvest, October 19-21, produced a total
of nearly 2,000 ears. Within only Replicate 1, for the 123 accessions of interest, archaeologists
harvested all ears produced by each of five plants not already harvested by the agronomists.
Harvested ears were collected from all plant locations: (a) on main central stalks (primary ear at
the top of the stalk, and potentially up to four more ears following in succession down the main
stalk); (b) on tiller stalks (substantial branches that arise from the base of the plant and surround
the main stalk); and (c) occasionally emerging from male tassels at the top of the plant. During
collection, the location of each ear (node number, primary or tiller stalk) was noted as the ear
was collected in labeled paper bags and logged. The leaf below the primary ear on the main stalk
was also collected, along with a husk from the primary ear, for future analyses to determine if
phytoliths and/or starch grains vary among maize accessions.
Maize drying. Once harvested, the maize was air-dried. Paper bags with ears inside were
laid out on tables and regularly turned for three weeks. Leaf and husk material from each
accession was segregated and stored for future research. Drying of the ears then continued for 30
hours in commercial plant dryers set at 65 oC. Drying removed moisture and killed insect adults
and larvae, so the maize could be safely stored. During the drying process, all ears were
inventoried and organized for analysis.
Maize ear analysis. The maize ears were analyzed by Arizona State University students,
under the direction of Cathryn Meegan. Traits recorded for all ears included: ear length (cm), ear
weight (g), shank (stalk the ear sits on) diameter (cm), number of kernel rows, and estimates of
missing kernels (Table 2). Ears were stored in large labeled zip-lock plastic bags for ease of
working with the collection.
Kernel color and endosperm types were observed on a selection of ears from each
accession (Table 3). Only fully formed ears were selected and a representative sample of the
variation within each plant was chosen. Colors included white, red, yellow, blue, brown, orange,
pink, purpleblack, and mixed colors (Figure 4). Kernels were cut in half to observe endosperm
types such as sweet, flour, flint, pop, and dent (Kisselbach 1949). Sweet kernels (composed of
sugar, water-soluble polysaccharide and relatively little starch) are completely translucent and
wrinkle notably when dried (Figure 5a). Flour kernels are composed of soft, white (starchy)
endosperm whose starch grains are rounded and loosely packed (Figure 5b). Flour kernels may
sometimes dent at the top if the kernel contains empty internal space resulting from incomplete
16
filling (Figure 5c). At times, flour kernels have a thin layer of hard, horny or corneous flint type
endosperm around the edges (Figure 5d). Flint and pop kernels are both characterized by a hard,
translucent outer endosperm layer composed of closely packed, angular starch grains with spaces
filled with protein (zein). This layer completely surrounds an internal portion of soft white flour
endosperm (Figure 6a). Pop kernels look like an extreme version of flint kernels, with a
relatively small internal portion of starchy flour endosperm (Figures 6b-c). Dent maize kernels
differ from flint and pop kernels in that they lack a layer of hard, corneous starch in the upper
part or apex of the kernel, causing a deep apical dent to form on the kernels as the flour
endosperm shrinks during drying (Figure 6d).
Table 2. Traits recorded on all ears.
Traits recorded on all ears Method
Ear length (cm)
From base of ear to the tip, including areas where kernels were
incomplete or absent; does not include the shank (stalk the ear
sits on).
Ear weight (g)
Full ear weight including kernels. Shank was removed if
possible.
Shank diameter (cm)
Measured just below the base of the ear, where the shank is
generally widest.
Row number
Determined at mid-ear by marking a kernel and then counting
kernel rows around the circumference.
Missing kernel estimate
If possible, a reasonable estimate of missing kernels was made.
Table 3. Traits recorded on a sub-set of ears. Ears were chosen to include variability visible
within each accession.
Traits recorded on select ears
Kernel color: white, red, yellow,
blue, brown, orange, pink,
purple/black, and multi-colored
Kernel endosperm: sweet, flour,
flint, pop, and dent
Ear diameter
Kernel streaking
Kernels pointed
Kernels with husk striations
Method
Ear was examined for a main kernel color (over 50% of the
kernels) and a secondary kernel color, if present (10 – 50%
of the kernels). Multi-colored ears displayed kernels of a
range of colors, none dominant.
Representative kernels on an ear were sliced open and
examined for the main endosperm (over 50% of the kernels)
and secondary endosperm (10-50% of the kernels) types.
Measured at mid-ear, to nearest 0.1 cm.
Noted when kernels appeared to have streaks or lines
running across them; color of streaking noted.
Noted when kernels came to a sharp point.
Noted when kernels bore the parallel imprints of tightly
adhering husks, along the long axis of the ear.
17
Figure 4: Examples of kernel colors. Top row of ears from left to right: white, red, yellow, blue
(dark blue, light blue) and brown. Bottom row of ears from left to right: orange, pink,
purpleblack, and two examples of mixed-colored ears.
18
5a: Tesuque
white sweet
(PI 218134)
Figure 5a: Sweet kernels have a completely
translucent endosperm, and the kernels
wrinkle significantly when they shrink
during drying.
5c: Santo
Domingo
white flour,
with shallow
dent
(PI 218130)
Figure 5c: The kernels occasionally have a
noticeable dent if a kernel has not filled
completely.
5b: Hopi
white flour
(PI 503567)
Figure 5b: Flour kernels have a soft, white,
easy-to-grind texture.
5d: Zia red
flour, with
some flint
(PI 218159)
Figure 5d: At times flour kernels have a thin
layer of hard, translucent endosperm visible
around the edges.
Figure 5: Examples of sweet and flour kernel endosperm. Kernels have been cut in half and
the embryo is visible to the lower right and lower left. All images photographed at 12x
magnification.
19
6a: Hopi red
flint
(PI 213733)
Figure 6a: Flint kernels have an endosperm
with a notable hard, corneous, translucent
outer layer that surrounds an internal portion
of softer flour endosperm.
Chapalote
brown pop
(PI 420245)
Figure 6c: Pop kernels appear as an extreme
form of flint endosperm, having a very thick
hard and translucent outer layer surrounding
a relatively small portion of internal flour
endosperm.
6b:Acoma white
pop
(PI 218140)
Figure 6b: Pop kernels appear as an extreme
form of flint endosperm, having a very thick
hard and translucent outer layer surrounding
a relatively small portion of internal flour
endosperm.
US 13 Mid-west
dent, with deep
dent
(Ames 26908)
Figure 6d: Dent kernels also appear as a
form of flint endosperm, whose hard
translucent endosperm is distributed on both
sides, but whose flour endosperm extends all
the way to the top of each kernel, allowing
the kernels to deeply dent as the flour
endosperm shrinks during drying.
Figure 6. Examples of flint, pop, and dent kernel endosperm. In every case, the kernel has
been cut in half, and the embryo is visible to the lower right and lower left. All images
photographed at 12x magnification.
20
Because the ears of some accessions contained kernels of different colors and/or endosperm
types, the “main” color and “main” endosperm type (expressed by more than 50% of kernels)
was recorded for each ear. If necessary, a “secondary” kernel color or endosperm type (expressed
by 10-50% of the kernels) was also recorded. At times these observations were easily made. At
other times, judgment calls were required in classification due to variability in kernels that
contained different proportions of soft flour and hard flint endosperm. Flour kernels with denting
caused by incomplete filling were always classified as flour kernels, and the denting was noted
as “shallow denting” under comments.
Additional observations were made on a sub-set of ears from each accession. These included:
ear diameter at mid-ear (cm), and some relatively rare kernel traits such as: color streaking;
presence of sharp points; and presence of husk striations (Table 3). Color streaking generally
appeared on light colored ears, with the streaks often being orange or red (Figure 7a). Red striped
kernels have been used as a charm for crop growth (Bohrer 1994: 493-494), and there may be an
underlying genetic reason why planting them in fields with maize of other colors appears to
impart vitality and bring better harvests. Possibly these streaks represent the presence of
transposable (jumping) genes, originally recognized as streaks in maize leaves by Barbara
McClintock (Keller 1983). Kernels that came to a sharp point (Figure 7b) were often classified as
having pop endosperm; at times individual silks were still attached to the sharp apex of these
kernels. Husk striations common in Chapalote maize and a few other accessions (Figure 7c)
occur when the vascular bundles within the inclosing husks imprint as indentations on the kernel
surface that are parallel to the long axis of the ear. These striations develop as the kernels are
formed; presumably tightly adhering husks provide more kernel protection from invasion by
fungi and/or insects. Finally, a trait minimally represented within the archaeological harvest was
that of ears that have fasciated or divided during development into two or more separate but
attached ears (Figure 7d). Such ears, especially those that are bifurcate (twins), are considered
“corn guardians” or “corn mothers” by indigenous farmers and are often selected to be placed in
storage rooms as guardians of the maize harvest, as they signify fertility and vitality, as well as
play an important role in prayer offerings (Bohrer 1994: 483, 494). The presence and expression
of the ramosa gene (Ra) family governs ear and tassel branching patterns in maize (Vollbrecht et
al. 2005). Presence and frequency of occurrence of such ears can be associated with genetic
markers in future research.
21
RESULTS
Field data
Weather data. Air temperature, precipitation, soil temperature, irrigation water
temperature, and evaporation data were summarized for the 2004 growing season (Table 4). The
total precipitation falling during the growing season was only 3.2 inches, an insignificant amount
of moisture for maize growth and maturation.
Growing season length. Signaling the start of the summer growing season, the
last day the minimum air temperature dropped to 32 °F was on May 1, 2004. Ending the season
on October 23, air temperature dropped to 31 °F immediately following the harvest. From the
effective planting date of May 21 until October 23, the 2004 frost-free growing season was 164
days in length.
CGDD units. Because the length of the frost-free season is not the only
component of temperature critical to maize development, CGDD units available between
planting and maturity (Muenchrath and Todey 2002) were calculated. The formula relevant to
maize is: [(daily maximum air temperature + daily minimum air temperature)/2] – 50 °F, with
the daily maximum upper temperature set at 86 °F, and the daily minimum set at 50 °F. As a C4
metabolism crop, the energy outlay for maize respiration generally exceeds its ability to capture
the sun’s energy and synthesize glucose at temperatures exceeding 86 °F. The ability of
accessions such as the Sonoran Desert landraces to thrive under high temperature conditions is of
genetic and physiological interest. The base temperature of 50 °F represents the temperature
below which enzymatic activities are limited, resulting in growth limitation. Explanations of
CGDD can be found at these web sites:
(a) http://www.agry.purdue.edu/ext/corn/
(b) http://ohioline.osu.edu/agf-fact/0101.html
(c) http://www.omafra.gov.on.ca/english/crops/pub811/1gddchu.htm
Midwestern U.S. elite dent types require an average of 2,400-3,200 CGDD, including: (a)
100 CGDD units for each vegetative growth stage, including emergence and each new leaf
produced; (b) 100 CGDD units for pollen shed, following tassel extrusion; and (c) an additional
1,000-1,300 CGDD units needed from pollination to kernel maturity. Earlier maturing maize
cultivars require fewer CGDD; later maturing varieties require more as they either develop more
leaves than earlier varieties, or progress through various growth stages at a slower rate of speed.
22
Table 4. Monthly weather data. Air temperature data reported by the New Mexico Climate Center (http://weather.nmsu.edu). All
other data gathered by NMSU Agricultural Science Center personnel. Summarized from May 21 (“effective planting date”) to October
3 (average maturity date) of accessions for the 2004 growing season.
Month
No. of
days
Precipitation
(inches/day)
Air temperature
(oF)
Soil temperature
(oF)
Irrigation water
temperature (oF)
Evaporation
(inches/day)
N=
X
s.d.
range
x
s.d
.
rang
e
tot
al
x
s.d.
range
x
s.d.
range
May
10
60.9
15.7
42-84
0
0
0
0
72.1
9.1
60-85
59.6
16.6
40-82
0.25
0.03
June
30
69.9
17.9
41-95
0.01
0.03
0.14
78.5
8.0
63-90
67.0
17.3
41-89
0.30
0.02
July
31
74.0
16.3
48-98
0.01
0.06
0.38
83.0
10.1
69-101
70.3
17.3
48-95
0.31
0.02
Aug
31
71.6
15.1
48-100
0.01
0.05
0.16
83.0
10.1
69-98
68.3
16.4
48-92
0.27*
0.03*
Sept
30
64.0
16.3
33-100
0.08
0.27
2.53
71.4
13.1
48-94
61.9
16.9
36-88
0.19
0.05
Oct
3
53.8
12.2
39-71
0
0
0.030.08
0.030.17
0.010.12
0.010.85
0
0
60.5
12.3
48-78
55.0
18.4
38-75
0.17
0.06
Totals, all
months
135
* Evaporation data not recorded for August 19-26, 2004.
3.21
X
s.d.
rang
e
Tota
l
0.190.3
0.230.34
0.260.35
0.210.32*
0.080.25
0.120.24
4.9
9.1
9.6
6.2*
5.7
0.52
29.7
23
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24
Figure 7a: Streaked kernels generally
contained red or orange streaks.
Figure 7b: Pointed kernels were often
observed on maize with pop endosperm.
Figure 7c: Husk striations on Chapalote and
a few other accessions formed because the
husks held so tightly during development
that their vascular bundles imprinted on the
kernels.
Figure 7d: Corn Guardian ears have
fasciated (divided) during development into
2 or more attached ears, in this case into 5
branches (only four of which are visible).
Figure 7: Examples of unusual kernel or ear traits, all photographed at 8x magnification
with the exception of the “Corn Guardian”
25
A longer period of dry matter accumulation post-flowering and pre-black layer provides a plant
with opportunity for increased yield, but also for longer exposure to environmental factors that
could limit yield. For information on maize growth stages see Kisselbach (1949) and Ritchie et
al. (1997).
In this study, in order to calculate the daily and CGDD units for the 2004 summer
growing season (Figure 8), the date of the first irrigation (May 21) is considered the “effective
planting date” when the kernels initiated germination. Since the majority of maize accessions
reached physiological maturity (defined below) between September 21 and October 14, the midpoint of this range (October 3) was chosen as the median maturity (black layer) date for the
experiment as a whole. Maturity dates for individual accessions are reported in Appendix 1.
Figure 8. Daily (DGDD) and cumulative (CGDD) growing degree days through the 2004
growing season. Reported from the start date of May 21 (effective planting date) to an end date
of October 3 (average accession maturity date). NMSU Agricultural Science Center at
Farmington.
Irrigation and fertilizer applications. In addition to the weather data, the
Agricultural Science Center kept records of the dates and amounts of irrigation water and
fertilizer added to the maize fields, as summarized here on a monthly basis (Table 5). A total of
23.45 inches of irrigation water applied over the growing season was spaced in daily or every26
other-day applications of 0.30 or 0.35 inches, ending September 17. On May 11, prior to
planting, staff applied a single application of both an herbicide (2.5 pints Bicep Lite II Mag and
1/8 pint Clarity per acre) and 200 lb/acre of a balanced 8-39-15 (8% Nitrogen-39% P2O5-15%
K2O) fertilizer. During the growing season, an additional 200 lb/acre of nitrogen fertilizer were
applied with the irrigation water spread over 1-2 week intervals. This resulted in a total nitrogen
application of 216 lb/acre throughout the 2004 growing season. Without leaching, and using an
average conversion ratio of 1.2 pounds of N per bushel, this N fertilizer application could
theoretically support a 180 bushel/acre production goal of modern farmers growing hybrid
maize.
Table 5. Monthly applications of irrigation water and nitrogen fertilizer. NMSU Agricultural
Science Center at Farmington, NM.
Month
Water Added
(inches)
Nitrogen Fertilizer
(lb/acre)
May
1.00
-
June
4.45
70
July
7.20
82
August
8.10
48
September
2.70
-
-
-
23.45
200
October
Totals
Maize data recorded during the growing season.
Planting and seedling emergence date(s). All maize was planted May 13-14 in
dry soil. The “effective” planting date of the first irrigation (May 21) immediately initiated
germination. Approximately seven days later on May 28, the first accession(s) for which at least
50% of the seedlings had emerged were noted. For all accessions, the 50% seedling emergence
dates ranged over 12 days from May 28 to June 10. These data will be fully reported by Lindsay
Werth.
Flowering date(s). During daily visits to the fields, dates of pollination (anthesis)
and silking (silks emerged to receive pollen grains) were monitored for six plants of each
accession. The dates when 50% of monitored plants within an accession shed pollen ranged over
seven weeks from July 19 to September 7; 90% anthesis ranged from July 21 to September 15.
27
Similar to pollination, the dates when 50% of the primary ear shoots of monitored plants within
an accession silked ranged from July 19 to September 7; 90% silking ranged from July 22 to
September 16. Coinciding periods of pollen shed and silk emergence helps ensure effective
pollination. These data will be fully reported by Lindsay Werth.
Maturity dates. The physiological maturity date of each accession was
determined via regular visits by the agronomists to one example of each accession, and the date
recorded when excised kernels were longitudinally cut to expose a black internal abscission layer
at the base of the kernel that signaled the kernel had ceased to absorb nutrients or moisture from
the mother plant, effectively terminating accumulation of dry matter. For 86 accessions for
which these data are available, achieving black layer maturity ranged over five weeks in
September and October (Appendix 1).
Plant height(s). Plant height was recorded at 3 weeks post-flowering to ensure
each plant was at maximum vegetative height, but not subject to error due to differences in
maturity, drying, and shrinkage. Lindsay Werth will report these data. During the October
harvest, archaeologists also measured the plant height of the 123 accessions discussed in this
report (Appendix 1). At that time, plant heights ranged from 1.3 to 3.4 m, a more than two-fold
difference between the shortest and the tallest accessions. Plant height results likely express
differences among the accessions in overall investment in vegetative structures.
The archaeological harvest.
Archaeologists harvested a total of 1,990 ears from 123 accessions, including 937 main
stalk ears, 1,049 tiller ears, and 4 tassel ears. The overall mean of ears harvested per five plants
of each accession is 16.2, and the mean number of ears per plant is 3.2. This mean ranged from 7
ears per plant for a Hopi Pueblo sweet maize (AMES #22634) to a single ear per plant for a
Jemez Pueblo orange flour maize (PI #218172). The descriptive and analytical results presented
below are based on a sub-set of 1,436 ears, after eliminating 34% of the total because they met
one of the following criteria:
(a) barren—the ear was primarily (over 50%) bare, or ear did not complete maturity and
had a very low weight (less than 40 grams) compared to others of the same plant;
(b) underdeveloped or undeveloped—very few of the kernels matured and the ears had a
very low weight (less than 40 grams) compared to others of the same plant;
28
(c) small—ears were fully developed, but significantly smaller than all the other ears in
the plot and weighed less than 40 grams;
(d) tassel or twin—tassel ears and corn guardians/twins were eliminated as unusual ear
examples.
Analysis results.
Estimated kernel weight per maize ear. Mean kernel weight per ear (g) is a
direct measure of grain yield, useful in archaeological maize subsistence models. Rather than
remove and weigh all kernels from all ears, 45 ears of varying size (large, small, and extra small)
were selected to assess confidence in predicting kernel weight from ear weight. A regression
analysis provided an equation (Figure 9) for estimating the grain yield (g) for every ear of each
accession. These estimates were included along with basic metric and non-metric observations in
an effort to classify all accessions into a reasonable number of morphological groups. These ear
weight estimates were also used to calculate grain yield per accession (Appendix 2).
Prediction of kernel weight from ear weight
250
y = 0.7848x
2
R = 0.957
Total kernel weight (g)
200
150
100
Small ears
50
Large ears
Extra small
ears
0
0
50
100
150
200
250
300
Ear weight (g)
Figure 9. Regression analysis results to predict kernel weight from ear weight. Based on 45 ears
ranging in size from large to extra small.
29
Maize morphological groups. Delineating a smaller number of morphologically distinct
maize ear groups within the 123 accessions has been accomplished in the following manner.
First, all accessions were subjectively arranged into four “alpha” groups, as follows. Alpha
groups 1-3 were all relatively long and slender (lower ratio or ear diameter to ear length), and
seem distinguishable from each other via overall ear size (large, small, medium) and shank size
(large, small, medium). Alpha group 4 included accessions with a number of modern hybrid dent
traits, such as short and broad ears (higher ratio of ear diameter to ear length) with a relatively
broad ear base, true “dent” type kernels (defined above), very high row number, and gaps
between pairs of kernel rows. Second, the accessions within each alpha group were then subdivided into “beta” groups, on the basis of main kernel color and main kernel endosperm texture.
In this manner, 27 separate morphological groups were defined, each with an alpha and a beta
designation (Table 6). It is important to note that the beta designations, based on main kernel
color and endosperm types (e.g. blue flour, yellow flour), can occur in one or more of the alpha
groups.
Based on multivariate statistical analysis, this subjective classification captured the major
differences in the ears quite well. This is supported by a principal components analysis of the
recorded (Table 2) and calculated (grain yield, ratio of ear diameter to ear length) ear characters
(Figure 10). In this analysis, the results indicate alpha group 4 (with modern hybrid dent traits) is
clearly separate from the others, and that the three remaining alpha groups grade between large
(alpha group 1), medium (alpha group 3), and small (alpha group 2). The same ear data were
subjected to a discriminant analysis, which defined three discriminant functions that together
account for 100% of the variance in this dataset, and that also classified 87.8% of the accessions
into the same alpha groups as did the original visual inspection (Table 7). Most of the accessions
(12.2%) that classified into other alpha groups than those of the original inspection appear to fall
near the boundaries of size categories. Although size corresponds to natural clusters in the
dataset, some accessions are clearly transitional between them.
For ease of reporting descriptive data, the original classification of the 123 accessions
into four alpha and 27 beta groups are further organized here by: (a) field observations; (b) ear
characters; and (c) kernel traits. Summarized data for each accession can be found in Appendix 1
(field observations), Appendix 2 (ear characters), and Appendix 3 (kernel traits).
30
Table 6. Morphological alpha-beta groups. The four alpha groups are mutually
exclusive. Beta groups (e.g. blue flour) can occur in more than one alpha group.
Alpha-beta
group
1-1
1-2
1-3
1-4
1-5
2-6
2-7
2-8
2-9
2 - 10
2 - 11
2 - 12
3 - 13
3 - 14
3 - 15
3 - 16
3 - 17
3 - 18
3 - 19
3 - 20
3 - 21
3 - 22
3 - 23
4 - 24
4 - 25
4 - 26
4 - 27
Ear size category Shank size
category
Large
large
Large
large
Large
large
Large
large
Large
large
small
small
small
small
small
small
small
small
small
small
small
small
small
small
Medium
medium
Medium
medium
Medium
medium
Medium
medium
Medium
medium
Medium
medium
Medium
medium
Medium
medium
Medium
medium
Medium
medium
Medium
medium
unspecified, dent
unspecified
unspecified, dent
unspecified
unspecified, dent
unspecified
unspecified, dent
unspecified
Main kernel color and endosperm
description
Blue flour
White or white and red flour
Orange flour
Mixed color flour
Mixed color flour or flint
White flour
White flint or flour
White sweet
White, yellow or pink flint or pop
Brown pop or flint
Yellow flour
Mixed color flour or flint
Mixed color flour or flint
Yellow flint or pop
White or white and red flour
White flour or flint
Yellow flint or flour
Purpleblack or blue pop, flint or flour
Yellow flour
Purpleblack flour
Blue flour
Red flint
Mixed color flint
White dent
Yellow dent
Mixed color dent
Orange or yellow dent, flint, or flour
Field observations. Field observations reveal some differences between the four
alpha groups (Table 8). Accessions in alpha group 2 (small ear type) produced the most ears per
plant (3.0) and required the fewest number of days from planting (132.1) and emergence (123.8)
to maturity. Alpha group 4 accessions produced the fewest ears per plant (2.0). Alpha groups 1, 3
and 4 required more days from planting and emergence to maturity than alpha group 2. Within
each alpha group, beta groups display variability in these field observations as well (Table 9).
31
3
Component 2 (22.2% of variance)
2
1
0
Alpha Group
4
-1
3
2
-2
1
-3
-2
-1
0
1
2
3
4
Component 1 (34.8% of variance)
Figure 10. Principal components analysis of 123 maize accessions. Based on a subjective
classification of all accessions into four alpha groups distinguished by size and other traits.
Alpha groups include: (a) ▲ large ears with large shanks; (2) ▼small ears with small shanks; (3)
■ medium-sized ears with medium shanks; and (4) o ears with modern hybrid dent traits.
Table 7. Discriminant analysis classification of alpha groups.
Original
group
membership
Predicted
Group
Membership
Alpha
1
Group
Count
1
36
%
2
3
4
1
2
3
4
0
5
0
85.7
0.0
12.8
0.0
Total
2
3
4
0
6
0
42
22
2
0
0.0
91.7
5.1
0.0
2
32
0
14.3
8.3
82.1
0.0
0
0
18
0.0
0.0
0.0
100.0
24
39
18
100.0
100.0
100.0
100.0
32
Table 8. Field observations, alpha groups.
Maize No. of
alpha accessions
group in each
alpha
group
1
42
2
24
3
39
4
18
No. of No. of
ears in plants in
each
each
alpha alpha
group group
508
203
331
119
446
189
151
85
Mean
ears
per
plant
2.76
3.03
2.60
1.96
SD Mean no. SD days - Mean no. of SD days ears of days - planting
days emergence
per planting
to
emergence to maturity
plant
to
maturity to maturity
maturity
1.41 139.27
7.08
131.28
7.09
1.55 132.11
7.62
123.82
7.64
1.33 137.06
6.60
129.50
6.37
0.98 138.00
6.93
129.89
7.74
Table 9. Field observations, beta groups.
Maize No. of
No. of No. of
beta accessions ears in plants in
group in each
each
each
beta group beta
beta
group group
1-1
9
132
45
1-2
11
117
50
1-3
6
76
28
1-4
7
86
33
1-5
9
97
47
2-6
7
94
35
2-7
6
85
30
2-8
5
75
23
2-9
3
31
15
2 - 10
1
15
5
2 - 11
1
14
6
2 - 12
1
17
5
3 - 13
12
123
58
3 - 14
5
58
25
3 - 15
6
76
27
3 - 16
4
47
21
3 - 17
1
6
5
3 - 18
1
6
4
3 - 19
2
31
10
3 - 20
1
9
5
3 - 21
4
54
19
3 - 22
1
11
5
3 - 23
2
25
10
4 - 24
13
105
60
4 - 25
2
18
10
4 - 26
2
21
10
4 - 27
1
7
5
Mean
ears
per
plant
3.1
2.6
3.0
3.0
2.3
2.9
3.1
3.6
2.3
3.0
3.0
3.4
2.4
2.5
2.9
2.4
1.8
2.0
3.2
2.0
3.2
2.4
2.9
2.0
1.9
2.2
1.4
SD Mean no. SD days - Mean no. of SD days ears of days - planting
days emergence
per planting
to
emergence to maturity
plant
to
maturity to maturity
maturity
1.3
141.8
6.8
133.6
6.8
1.3
140.0
7.7
132.3
7.7
2.1
140.0
6.9
131.6
7.4
1.4
132.3
6.5
124.5
6.4
1.0
139.4
5.3
131.4
5.3
1.5
127.2
3.1
118.3
3.2
2.0
131.0
3.0
123.7
3.4
1.5
132.5
8.8
124.8
8.4
1.1
134.3
8.9
125.3
9.2
0.7
1.1
146.0
0.0
137.0
0.0
1.1
144.0
0.0
135.7
0.6
1.3
137.8
6.1
130.2
5.9
1.6
131.8
6.1
124.3
6.0
1.5
138.0
8.5
130.3
8.2
1.0
134.0
8.4
126.8
7.5
0.8
136.0
0.0
127.3
0.6
0.8
137.0
0.0
129.3
0.6
1.3
137.5
0.5
129.5
2.4
0.7
130.0
0.0
123.3
0.6
1.3
144.0
0.0
136.6
0.5
1.1
136.0
0.0
129.0
1.0
1.6
139.5
1.6
132.2
1.8
1.0
138.0
0.0
129.3
0.6
0.7
1.2
130.0
0.0
121.3
2.1
0.5
146.0
0.0
139.0
0.0
33
Ear characters. Ears vary notably among the alpha groups in their morphometric
characters of ear length, weight, diameter; shank diameter; row number; estimated mean grain
weight (g) per ear; and ratio of ear diameter to ear length (Table 10). Alpha group 1 ears
(Figure 11) are longest in mean length (21.1 cm), have the broadest mean shank diameter
(2.1 cm), the highest mean ear weight (173.9 g), and the highest estimated mean kernel weight
(136.5 g) per ear (Table 10). Alpha group 2 ears (Figure 12) are shortest in mean length
(16.6 cm), have the narrowest shanks (1.3 cm), and both the lowest mean ear weight (86.8 g) and
estimated mean grain weight per ear (27.3 g). The ear characters of alpha group 3 ears
(Figure 13) fall between alpha groups 1 and 2. Their wide mean ear diameter (4.8 cm), highest
mean row number (15.4), and highest ratio of ear diameter to ear length (0.3) distinguish alpha
group 4 ears with their hybrid dent traits (Figure 14). Variability in these ear characters occurs
among beta groups within each alpha group (Table 11).
Kernel traits. The beta group kernel traits of main color and main endosperm
type also vary notably among the four alpha groups (Table 12). Alpha group 1 ears (Figure 11)
have kernels that are predominantly of flour endosperm (92.9 %), but that are a diversity of
colors, including blue (31.3%), white (30.1%), orange (19.9%), and lesser amounts of red
(12.2%), yellow (3.2%), purpleblack (1.8%), or multi-colored kernels (1.6%). In sharp contrast,
the main endosperm types of alpha group 2 ears (Figure 12) include flour (47.7%), sweet
(21.8%), flint (18.7%), and pop (11.5%) kernels, with a negligible presence of dent kernels
(0.3%), and very few main ear colors, primarily white (80.7%), yellow (12.7%) and brown
(4.5%). Alpha group 3 ears (Figure 13) are similar to alpha group 1 in terms of color diversity,
and to alpha group 2 in terms of endosperm variety. Alpha group 4 ears (Figure 14) have
predominantly dent kernels (98.0%) that are either white (73.5%), yellow (19.2%), or orange
(7.3%) in color. Beta groups also vary for kernel traits (Table 13).
Most of the beta groups within the alpha groups consist of one main color and one main
endosperm type (Table 6). However, there are accessions within each alpha group that have ears
of different main color(s) and/or different main endosperm type(s), and can even include
individual ears with kernels that vary in these traits. This variability has been classified within
the beta groups as, for example, “white flint or flour”, “mixed color flour or flint”, “purpleblack
or blue pop, flint or flour”, etc. These mixed color and endosperm accessions may represent
maize that has developed from intermixing germplasm of distinctive maize landraces, each with
34
Table 10. Ear characters, alpha groups.
Maize
No. of
No. of ears Mean SD ear Mean
alpha accessions in each
ear
diam. shank
group in each
alpha
diam. (cm) diam.
alpha
group
(cm)
(cm)
group
1
42
508
4.2
0.5
2.1
2
24
331
3.3
0.4
1.3
3
39
446
3.9
0.4
1.6
4
18
151
4.8
0.5
1.5
SD
shank
diam.
(cm)
0.7
0.4
0.5
0.6
SD
Mean SD ear Mean SD ear Ratio of
Mean
SD Estimated
estimated ear row
mean
row
ear
length
ear
ear
ear
weight weight kernel mean kernel number number length (cm) diameter
(g) weight per weight per
(cm)
to ear
(g)
ear (g)
ear (g)
length
173.9
65.4
136.5
51.4
14.7
2.5
21.1
4.8
0.2
86.8
34.8
68.1
27.3
12.1
2.2
16.6
3.6
0.2
136.8
47.4
107.3
37.2
13.6
2.2
19.0
3.9
0.2
159.1
71.7
124.9
56.3
15.4
2.0
17.0
4.1
0.3
35
a single main color and single endosperm type. These mixed accessions may be distinct
landraces in their own right, or represent temporary cross-breeding of maize landraces for
purposes such as animal feed. Whether or not these mixed accessions represent landraces
perpetuated through time is unknown.
In terms of mixed colors, however, having white and red ears in the same accession
appears to have an underlying genetic explanation. Although color is very complex (discussed
above), red is the best known of the pericarp colors and occurs frequently in open-pollinated
maize, having disappeared from the carefully controlled hybrids (Weatherwax 1954: 204). Since
red is a dominant color, it appears in the form of an occasional brilliant red ear in otherwise pure
yellow or white varieties, which once gave it a prominent place in New England husking
festivities of colonial days (Weatherwax 1954: 204). In addition, among indigenous groups red
maize appears spontaneously in fields where large white kernels are planted (Bohrer 1994: 510511). For these reasons, accessions with “white and red” ears have been grouped with those
accessions having only white ears.
Ears with “pointed” kernels or with “streaked” kernels are distributed widely among the
beta groups to varying degrees (Table 13). Although kernels that come to a sharp point are
usually associated with pop type endosperm, a range of kernel “pointedness” has been captured
in many accessions. Red or orange “streaking” is also differentially distributed among many of
the beta groups, and would provide an advantage if it represents a visible manifestation of some
underlying genetic ability to instill crop vigor, as some indigenous groups consider red striped
kernels to be a “charm for crop growth” (Bohrer 1994: 493-494).
36
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37
Figure 11: Representative ears of alpha
group 1. Ears in this photo include (from
left to right) Santo Domingo blue flour (PI
218156 ), Zia white or white and red flour
(PI 218159), Hopi (Moencopi) white or
white and red flour (PI 218176), Acoma
orange flour (PI 218167), Laguna mixed
color flour (PI 218170), Hopi mixed color
flour or flint (NSL 68327).
Figure 12: Representative ears of alpha
group 2. Ears in this photo include (from
left to right) Papago white flour (PI
218185), Pima-Papago white flour or flint
(PI 503563), Hopi (Moencopi) white sweet
(PI 218174), Mexico-Chihuahua white,
yellow or pink pop or flint (PI 484413),
Mexico, Sinaloa (Chapalote) brown pop or
flint (PI 420245), Papago yellow flour (PI
213714), Papago mixed color flour or flint
(PI 218179).
38
Figure 13: Representative ears of alpha
group 3. Ears in this photo include (bottom
row from left to right) Cochiti mixed color
flour or flint (PI 218151), Taos yellow flint
or pop (PI 218149), Hopi white or white
and red flour (NSL 68334), Hopi white or
white and red flour (NSL 68334), Hopi
white flour or flint (NSL 68324), Navajo
yellow flint or flour (PI 213739), (top row
from left to right) Mexico-Chihuahua
purpleblack or blue pop, flint or flour (PI
484482), Tesuque yellow flour (PI
218136), Hopi-Hotevilla purpleblack flour
(PI 503566), Santa Domingo blue flour (PI
218143), Hopi red flint (PI 213733), Hopi
mixed color flint (NSL 67060).
Figure 14: Representative ears of alpha
group 4. Ears in this photo include
(bottom row from left to right) Hopi white
dent (NSL 67048), San Felipe yellow dent
(PI 218154), Hopi mixed color dent (NSL
68335), Jemez orange or yellow dent, flint
or flour (PI 218171), (top row from left to
right) Mid-western dent (Ames 19097),
Mid-western dent (Ames 26908).
39
Table 11. Ear characters, beta groups.
Maize No. of
No. of Mean SD ear Mean
SD
Mean
SD Estimated
SD
Mean SD ear Mean SD
Ratio of
beta accessions ears in ear diam. shank shank ear
ear
mean
estimated ear row
row
ear
ear
ear
group in each
each diam. (cm) diam. diam. weight weight kernel
mean kernel number number length length diameter
beta group beta (cm)
(cm) (cm)
(g)
(g) weight per weight per
(cm) (cm)
to ear
group
ear (g)
ear (g)
length
1-1
9
132
4.0
0.4
1.8
0.6
157.7
41.6
123.8
32.8
14.99
2.43
20.7
4.0
0.2
1-2
11
117
4.3
0.5
2.2
0.7
182.0
71.5
142.8
56.1
15.15
2.73
21.4
5.2
0.2
1-3
6
76
4.4
0.6
2.4
0.7
188.6
86.4
148.0
67.8
14.43
3.00
20.7
5.00
0.2
1-4
7
86
4.1
0.4
2.2
0.9
167.2
67.4
131.2
52.9
14.19
2.11
20.9
5.1
0.2
1-5
9
97
4.2
0.5
2.1
0.7
180.8
59.4
141.9
46.6
14.19
2.13
21.5
4.8
0.2
2-6
7
94
3.4
0.4
1.4
0.3
92.4
35.7
72.5
28.0
11.87
1.86
17.4
3.3
0.2
2-7
6
85
3.2
0.4
1.2
0.5
79.8
34.2
62.6
26.9
10.64
2.11
17.0
3.9
0.2
2-8
5
75
3.5
0.5
1.4
0.3
86.9
37.3
68.2
29.3
13.16
1.96
15.0
3.1
0.2
2-9
3
31
3.2
0.2
1.1
0.4
93.3
26.8
73.2
21.0
13.48
2.00
18.0
3.4
0.2
2 - 10
1
15
3.0
0.4
1.0
0.2
53.0
18.7
41.6
14.7
12.71
0.99
13.1
1.4
0.2
2 - 11
1
14
3.4
0.3
1.3
0.2
92.3
36.6
72.4
28.7
12.43
0.85
16.8
4.8
0.2
2 - 12
1
17
3.4
0.2
1.3
0.2
102.9
20.6
80.8
16.2
11.65
1.90
17.5
2.3
0.2
3 - 13
12
123
3.8
0.4
1.6
0.6
141.2
45.3
110.8
35.6
14.10
2.43
19.4
4.0
0.2
3 - 14
5
58
4.0
0.4
1.5
0.6
159.2
47.8
124.9
37.6
13.02
1.86
19.8
3.8
0.2
3 - 15
6
76
3.8
0.4
1.8
0.5
132.4
52.0
103.9
40.8
13.12
2.00
18.6
3.9
0.2
3 - 16
4
47
3.9
0.3
1.2
0.4
120.2
62.0
94.3
48.6
13.45
2.56
17.9
4.2
0.2
3 - 17
1
6
4.0
0.4
1.8
0.5
121.9
39.2
95.7
30.8
15.33
2.07
16.0
3.9
0.3
3 - 18
1
6
3.9
0.2
1.2
0.2
131.1
18.9
102.9
14.8
12.67
1.03
16.8
3.1
0.2
3 - 19
2
31
3.9
0.3
1.4
0.4
122.5
31.1
96.2
24.5
13.81
1.66
18.2
3.6
0.2
3 - 20
1
9
3.6
0.2
1.4
0.3
132.6
30.0
104.1
23.6
13.56
1.33
21.2
4.8
0.2
3 - 21
4
54
3.9
0.3
1.8
0.5
128.8
36.9
101.1
29.0
14.43
1.96
19.4
3.9
0.2
3 - 22
1
11
3.5
0.2
1.9
0.6
120.4
29.0
94.5
22.7
13.64
1.75
18.4
2.9
0.2
3 - 23
2
25
4.0
0.4
1.5
0.4
155.6
43.8
122.1
34.4
12.64
2.56
19.2
3.3
0.2
4 - 24
13
105
4.8
0.5
1.3
0.4
142.5
56.2
111.9
44.1
15.43
1.99
16.4
3.4
0.3
4 - 25
2
18
4.9
0.3
1.6
0.5
234.2
71.6
183.8
56.2
15.11
1.57
20.1
4.7
0.2
4 - 26
2
21
4.7
0.4
1.9
0.4
138.8
58.4
108.9
45.9
15.71
2.39
15.00
3.4
0.3
4 - 27
1
7
5.1
0.4
2.7
0.8
275.7
93.7
216.3
75.5
14.86
1.95
22.6
4.7
0.2
40
Table 12. Kernel traits, alpha groups.
Maize
No. of
alpha accessions
group in each
alpha
group
1
2
3
4
42
24
39
18
No. of % ears % ears
ears in with
with
each pointed streaked
alpha kernels kernels
group
508
331
446
151
27.17
23.26
24.44
30.46
31.69
22.66
36.32
15.89
% % ears % ears
ears with
with
with brown multiblue kernels colored
kerkernels
nels
31.30
1.57
0.60 4.53
19.96
2.24
%
ears
with
orange
kernels
19.88
1.12
7.28
% % ears
ears
with
with purple
pink /black
kerkernels
nels
1.77
1.51
0.90
5.61
%
%
ears ears
with with
red white
ker- kernels
nels
12.20 30.12
80.66
9.19 37.22
73.51
%
ears
with
yellow
kernels
3.15
12.69
23.77
19.21
%
ears
with
dent
kernels
%
ears
with
flint
kernels
6.50
0.30 18.73
0.45 30.72
98.01 0.66
%
%
%
ears ears ears
with with with
flour pop sweet
ker- ker- kernels nels nels
92.91 0.59
47.73 11.48 21.75
64.80 4.04
1.32
41
Table 13. Kernel traits, beta groups.
Maize
No. of
No. of % ears % ears
% % ears % ears % ears
beta accessions ears in
with
with
ears with
with
with
group in each each beta pointed streaked with brown multi- orange
beta group group kernels kernels blue kernels colored kerkerkernels
nels
nels
1-1
1-2
1-3
1-4
1-5
2-6
2-7
2-8
2-9
2 - 10
2 - 11
2 - 12
3 - 13
3 - 14
3 - 15
3 - 16
3 - 17
3 - 18
3 - 19
3 - 20
3 - 21
3 - 22
3 - 23
4 - 24
4 - 25
4 - 26
4 - 27
9
11
6
7
9
7
6
5
3
1
1
1
12
5
6
4
1
1
2
1
4
1
2
13
2
2
1
132
117
76
86
97
94
85
75
31
15
14
17
123
58
76
47
6
6
31
9
54
11
25
105
18
21
7
32.58
25.64
21.05
38.37
16.49
17.02
18.82
6.67
58.06
73.33
50.00
23.53
17.89
6.90
22.37
44.68
33.33
0.00
3.23
0.00
37.04
54.55
64.00
31.43
5.56
28.57
85.71
36.36
32.48
9.21
22.09
50.52
14.89
15.29
48.00
29.03
84.85
% % ears %
ears with
ears
with purple with
pink /black red
ker- kerkernels nels
nels
%
%
%
ears ears ears
with with with
white yellow dent
ker- ker- kernels nels nels
3.79
3.79
1.71
1.32
9.30
0.76
34.88
17.53
1.06
2.33
5.15
4.27
94.74
20.93
6.19
2.33
2.06
16.13
0.76 6.06
22.22 71.79
3.95
8.14 22.09
28.87 40.21
88.30
100.00
100.00
29.03
10.64
1.06
54.84
100.00
17.65
52.03
22.41
28.95
29.79
33.33
50.00
25.81
55.56
31.48
36.36
40.00
5.71
44.44
47.62
5.88
22.76
1.72
4.88
1.72
3.25
1.63
1.32
2.63
33.33
9.76
100.00
88.24 5.88
12.20 30.89 14.63
3.45 5.17 87.93
7.89 88.16
1.32
100.00
2.13
100.00
66.67
%
ears
with
flint
kernels
%
%
%
ears ears ears
with with with
flour pop sweet
ker- ker- kernels nels rnels
3.79
96.21
100.00
100.00
96.51
71.13 3.09
91.49
51.76 3.53
1.33 96.0
77.42
66.67
100.00
82.35
78.05
3.45 22.41
98.68
40.43 4.26
33.33
16.67 50.00
100.00
100.00
98.15
9.09
3.49
25.77
7.45
44.71
2.67
22.58
33.33
17.65
21.95
74.14
53.19
66.67
33.33
100.00
100.00
94.44
18.18
20.00
12.00
0.95
23.81
71.43
3.70 1.85
81.82
28.00 40.00
95.24
3.81
100.00
52.38 23.81
28.57
1.85
90.91
100.00
100.00
94.44
5.56
100.00
71.43 14.29 14.29
42
DISCUSSION
Geographical/cultural distribution of alpha groups. The four alpha groups that are
distinguishable in this study are also correlated geographically and culturally. The large ears with
large shanks that come in a diversity of colors and that are composed almost entirely of flour
kernels (alpha group 1) are strongly associated with the Rio Grande and Western Pueblos. Of the
42 accessions within this group, only 10 were collected from Navajo (N = 5) and Lower
Colorado River Havasupai (N = 5) farmers, who presumably received these large-eared flour
maize types from Rio Grande or Western Puebloans as gifts or in trade. Some alpha group 1
accessions have particularly large ears, especially those of the Pueblos of Isleta, Santo Domingo,
Zia, Acoma, Mesita, Jemez, Tesuque, and Hopi. Of the 13 accessions with the highest mean ear
weights (all over 200.0 g), ten were alpha group 1 accessions collected from Rio Grande or
Western Puebloans. The remaining three, with traits of modern hybrid dents (alpha group 4),
were also collected from this same group of farmers. The history of development of these large
ears with high average ear weight remains to be investigated. It will be interesting to determine if
these large ears contain germplasm from modern hybrid dent ears, or if Puebloans developed
these large flour kernel maize ears prior to the era of modern hybrid dent maize. In addition to
their large size, the diversity of colors in alpha group 1 (blue, white, red, orange, and yellow) has
perhaps been retained by Puebloans for both ceremonial needs and culinary preferences (Ford
1980).
The small ears with small shanks, limited kernel colors, and a diversity of endosperm
types (alpha group 2) are strongly associated with the southern Arizona and northern Mexican
groups. Thirteen accessions within this group of 24 accessions were collected from Tohono
O’odham, Akimel O’odham, and Mexican farmers. The rest were accessioned from the Walapai
(N = 1) and Mojave (N = 2) groups of the Lower Colorado River, and from Western Puebloan
(N = 5) and Navajo farmers (N = 2), again suggesting that maize was being moved
geographically out of the Sonoran Desert region and then grown by other Native American
groups. However, this may also be a feature of maize landraces supported by low water
availability, rather than reflecting directional migration/improvement efforts. These small ears
may be best adapted to the high temperature and arid growing conditions of the Sonoran and
Chihuahuan desert regions, but seem to also do well in both Lower Colorado River and Colorado
Plateau settings. The limited ear colors (white, yellow, brown) documented in this study do not
43
represent the range of maize ear colors (white, yellow, blue, red and purple) reported historically
for Tohono O’odham and Akimel O’odham groups earlier in the 20th century (Castetter and Bell
1942:79-89), so possibly some of the colors are no longer being grown or were not made
available to collectors and have not been included in this study. However, the alpha group 2 does
include a wide range of kernel endosperm types (flour, sweet, flint, and pop) serving a range of
culinary needs, and as formerly reported (Castetter and Bell 1942: 79-89). The only ears in this
study with brown kernels (PI 420245, Mexico (Sinaloa)) are in this alpha group, and appear to
have all the traits of Chapalote maize, a long-standing type in the Southwest (Adams 1994). The
only ears with sweet kernels are also within this alpha group.
Thirty of the 39 medium-sized accessions (alpha group 3) were collected from Rio
Grande and Western Puebloan farmers. The remaining were from Apache (N = 1), Navajo
(N = 4), Mexican (N = 3), and Sonoran Desert (N = 1) groups. This intermediate alpha group is
the least distinct of the four alpha groups, and may represent some level of inter-breeding
between alpha group 1 and alpha group 2, resulting in gradation in ear characters and kernel
traits. The color range in this group (white, yellow, purpleblack, blue, and red) is similar to that
of alpha group 1, and the endosperm type range (flour, flint and pop) is similar to that of alpha
group 2. Alpha group 3 contains the only examples in this study of purpleblack flour maize ears
(PI 503566, Hopi (Hotevilla)) and red flint maize ears (PI213733, Hopi); possibly they are also
fairly rare historic types.
The final group of 18 accessions (alpha group 4) contains ears with traits similar to those
of modern hybrid dent maize, including deeply dented flint type kernels, high mean row number,
and relatively wide mean ear diameter and shank diameter (Table 14). Although the alpha group
4 accessions were all collected from Native American farmers, it is reasonable to assume that
these farmers received hybrid dent ears or kernels at various times during the historic period,
grew some in their fields, and then handed them over when asked for examples of their maize.
These included Hopi farmers (N = 8 accessions), Tohono O’odham farmers (N = 6 accessions),
and farmers from Mexico (N = 1), the Rio Grande Pueblos (N = 2), and one Apache group.
The fact that the alpha group 4 accessions are smaller than modern hybrid dent maize in regard
to mean ear weight and mean ear length (Table 14) suggests some intermixing of germplasm
with Native American maize may have occurred.
44
Table 14. Alpha group 4 ear characters and kernel traits compared to modern hybrid dent maize.
Ames 19097 and Ames 26908 both grown in 2005 Farmington field trials.
Maize
Number Mean ear
of ears
weight (g)
Alpha group 4
Ames 19097
(B73 x MO17)
Ames 26908
(US 13)
151
9
159.1
258.2
Mean no.
of kernel
rows
15.4
16.0
7
222.2
16.6
Mean ear
diameter
(cm)
4.8
4.9
4.6
Mean ear
length
(cm)
16.9
20.7
Mean shank
diameter (cm)
21.4
1.5
1.5
1.4
Shared maize. The alpha group organization discussed above suggests that Rio Grande
and Western Puebloan people shared large-eared flour maize with each other, and with Navajo
and Havasupai farmers. Southern Arizona and northern Mexican farmers shared maize with each
other, and with Lower Colorado River, Western Pueblo, and Navajo farmers. Formerly mobile
groups (Apache, Navajo) received their maize from more settled groups, and the presence of
Apache and Navajo maize accessions within all four alpha groups bears this out.
Population genetic analyses. Population genetic analyses that aim to reveal the
relatedness of the maize landraces, possibly including a chronological sequence of their
development, are planned for leaf samples captured on Whatman DNA Capture cards from these
experiments. One significant potential outcome from such analyses might be the recognition of
which alpha – beta groups have the longest history in the Southwest, in comparison to the
available archaeological perspective on this issue (summarized in Adams 1994). For example, at
this time brown pop or flint Chapalote (PI 420245) appears to be a fairly early entrant, while
maize with 8-rows of kernels (e.g. NSL 2830) reflects a later entry into the Mogollon highlands
(Adams 1994). Results from population genetic analyses could support or refute these
hypotheses.
Inference of relatedness among the landraces could be made using organelle or nuclear
DNA, applying methods that include phylogenetic analysis of sequences at a particular locus,
examination of the distribution of molecular markers present within each landrace, etc. However,
recent work demonstrates that the organelle genomes are probably not appropriate for the
purposes of inferring relatedness among maize landraces. Comparisons within the genus Zea
reveal almost no differences in known content among seven mitochondrial genomes, but do
reveal major rearrangements, large duplications, and insertions of foreign DNA of unknown
45
origin (Fauron et al. 2005). Although these rearrangements could possibly provide a means for
judging intra-maize relatedness, rearrangements in the short-term (i.e., within a few generations)
and rearrangements that are the same but that occur independently would lead to errant
conclusions. A similar argument can be made against the use of the maize chloroplast genome
for population genetic analyses: although the sequence of the maize chloroplast genome is
almost invariant, changes in the structure of DNA molecules and the amount of DNA per
chloroplast during development are known to occur (Oldenburg and Bendich 2004). Studies of
maize isozymes (Doebley et al. 1983), although informative, are labor intensive and have been
surpassed in recent years in favor of a focus on other molecular maize markers (Laborda et al.
2005).
Relative to the organelle genomes, nuclear genomes show fewer rearrangements and
enough sequence variability for use to infer relatedness among the maize landraces. In addition,
nuclear DNA, of sufficient quantity and quality required for amplification via the polymerase
chain reaction (PCR), has been extracted from dried maize cobs successfully (Schneerman et al.
2002). Using this protocol, good correlation of amplified alleles between the cob and leaf of the
same individual has been demonstrated.
Because allelic representation of each landrace at a given locus is expected to be variable,
phylogenetic analyses of amplified sequences from any given locus would likely not yield the
desired results. This leaves molecular marker analyses of genomic DNA as a reasonable method
for inferring relatedness. PCR-amplified maize microsatellite markers (also called simple
sequence repeats or SSRs for short) from the nuclear genome presently show great variability
within populations, provide a reliable means to measure intraspecific variation, and would be
useful in evolutionary studies (Matsuoka et al. 2002a).
The alpha - beta group classification presented here now provides a framework for
organizing microsatellite marker analyses. For example, the nine large blue flour accessions in
alpha - beta group 1 - 1 were all collected from Rio Grande (San Felipe, Santo Domingo, Santa
Clara) or Western Pueblos (Mesita, Zuni, Hopi), and Navajo farmers. Likewise, 11 white or
white and red flour accessions in alpha - beta group 1 – 2 represent Rio Grande farmers from a
different combination of Pueblos (Santo Domingo, Isleta, Zia, Jemez), Western Pueblos (Mesita,
Acoma, Hopi), and Navajo and Havasupai farmers. For each alpha-beta group, microsatellite
markers can be compared/contrasted to evaluate the degree of each maize accession’s
46
similarity/dissimilarity to its larger group, especially for those accessions that are geographically
or culturally distant from the rest (e.g. in these examples maize grown by Navajo or Havasupai
farmers). At that point, it may become clearer whether all large blue flour maize accessions, for
example, are closely related, or if some have developed independently due to geographic and/or
cultural isolation. Speculation on the direction of exchange or geographic origin of the maize
accessions might also be possible.
Microsatellite marker comparisons could then be extended to beta groups that occur
within more than one alpha group (e.g. all blue flour maize accessions, regardless of size), and
eventually to comparisons among the alpha groups themselves. Based on morphological
differences reported here, it is anticipated that alpha groups 1, 2 and 4 will reveal some level of
genetic distance at the population or landrace level, and alpha group 3 will appear transitional
between alpha groups 1 and 2.
As an added bonus, uncharred ancient maize cobs have preserved in cave and rockshelter
deposits and even in unprotected archaeological sites in the Southwest over a period of the last
3,000+ years (Adams 1994). These ancient specimens could be similarly characterized by
extracting nuclear DNA and amplifying microsatellite markers. Results could then be compared
to the molecular studies centered on the morphological groups delineated in this study. Such
comparisons might illuminate relationships and movement of maize landraces within geographic
and/or cultural contexts.
Implications for archaeological subsistence models. Archaeological models that
include growing season parameters and estimates of grain yield will benefit from the data
gathered in this experiment. Data of particular relevance include the required number of growing
season days from seedling emergence to maturity, the heat units (CGDD) within a growing
season required to produce mature kernels of different landraces, the number of ears produced
per plant, and data on grain yield per ear and per plant. In this section, Native American maize
accessions are discussed using an organization of geographic location/cultural affinity.
Temperature parameters important to maize maturity. Because killing frosts
are not a significant problem for maize plants prior to seedling emergence, the number of frostfree days between seedling emergence and maturity for 86 accessions for which maturity dates
were recorded are reported (Table 15). In this study, Native American accessions required a
mean of 128 days from emergence to maturity, with a range of 111 to 144 days. Variability
47
among major geographic/cultural groups seems negligible, although individual landraces of
maize can vary notably for this trait (reported in Appendix 1). Since elevation is a powerful
selection factor, future examination of elevation associated with ethnographic groups and
landraces should be accomplished.
Table 15. Mean frost-free days and CGDD (Cumulative Growing Degree Day) units for
geographic/cultural groups. Calculated only for 86 Native American accessions for which
maturity dates were available. NMSU Agricultural Science Center at Farmington, NM.
Geographic/
Cultural groups
Rio Grande and
Western Pueblos
Southern Arizona
and Northern
Mexico groups
Apache, Navajo,
Lower Colorado
River groups
Totals
No. of
Mean days
accessions from
per group emergence
to maturity
53
130
Range of days
from
emergence to
maturity
115-144
Mean
CGDD from
emergence
to maturity
2388
Range of
CGDD from
emergence to
maturity
2256-2479
11
125
111-137
2119
2193-2450
21
126
114-137
2343
2229-2445
86
128
111-144
2342
2193-2479
Although this study reports a mean of 125 days (range 111-137) from emergence to
maturity for southern Arizona and northern Mexican accessions, these numbers may be high
because of the Colorado Plateau setting of this experiment. Southern Arizona “60-day” Tohono
O’odham (Papago) maize has been reported to require 50-70 days from planting to flowering
(anthesis and silking) plus an additional 30 days from flowering to maturity, for a total of 80-100
days (Muenchrath 1995: 11), significantly lower than the 125 days reported here. Historically,
both Tohono O’odham (Papago) and Akimel O’odham (Pima) maize landraces have been
double-cropped during a growing season in the Sonoran Desert. It is possible that the greater
number of days required to reach maturity by these accessions at the elevation of the Colorado
Plateau is due to generally lower day-time and night-time temperatures, requiring more days to
accumulate the necessary CGDD units (see discussion below). Northern Mexican (Coahuila,
Sinaloa, Chihuahua, Sonora) accessions sensitive to day-length may have slowed their growth
and development in response to the relatively longer summer days of the northern Farmington
experimental field location in relation to their normal southern locale. Some of the Mexican
48
accessions were excluded from this report because they failed to produce any kernels at all, or
developed ears with exceedingly poor kernel fill, presumably due to relatively late flowering.
CGDD units. Maize accessions organized by geographic/cultural group reached
physiological maturity within a range of 269 CGDD units of each other (Table 15). Fifty-three
accessions from the Rio Grande and Western Pueblos required a mean of 2,388 CGDD, and
eleven southern Arizona/northern Mexican accessions required 2,119 CGDD. For the reasons
cited immediately above, CGDD data reported here for southern Arizona and northern Mexican
accessions may be incorrectly estimating the number of heat units required from emergence to
maturity, or perhaps it took longer to accumulate them within this Colorado Plateau setting.
Experimental grow-outs closer to their normal environments might provide a better assessment
of their CGDD requirements. At that time, investigations could evaluate whether Native
American maize adapted to the extremely hot and arid conditions of the Sonoran Desert can
grow and develop above the 86 °F maximum temperature of the CGDD formula.
Maize grain yields. Although maize crop dependability and predictability must
rank as significant traits for farmers, the estimated mean grain yield (g) per ear and per plant are
also important. Yield per ear (as mean estimated kernel weight) is reported here for each
accession (Appendix 2), alpha group (Table 10), and beta group (Table 11). When
geographic/cultural sub-groups are examined within each alpha group (Table 16), Native
American maize accessions grown by Rio Grande and Western Pueblo farmers average 150.1
grams of kernel weight per ear. In sharp contrast, southern Arizona and northern Mexican maize
accessions produce on average 70.1 g of kernels per ear, due likely to both small ear size and
lower mean row number, as compared to Rio Grande and Western Puebloan maize. As
previously mentioned, it cannot be known what maize growth, ear, or kernel traits may have
been affected by growing southern desert-adapted maize accessions in the Colorado Plateau
setting of these experimental fields.
Mean kernel weight (g) per plant is also a useful figure for archaeological subsistence
models. This is especially important, as the mean number of ears produced per plant ranges
between 1.4 and 3.4 for the beta groups (Table 9). Under the optimal irrigation conditions of this
field experiment, plants with fully formed ears produced a mean of 182.3 g (0.1823 kg) to 390.6
g (0.3906 kg) of maize kernels, depending on geographic/cultural group (Table 16). However,
49
these optimal yield estimates produced via intensively irrigated fields do not approximate
expectable and predictable yields affected by less than optimal moisture conditions.
Table 16. Mean estimated kernel weight per ear and per plant, and mean row number for alpha
groups and geographic/cultural subgroups. Alpha group 4 accessions are those with modern
hybrid dent traits.
Alpha groups
Geographic/
cultural groups
within each alpha
group
Alpha group 1
Number of
accessions per
group/ears
per group
42/508
2.5
14.7
Estimated
mean
kernel
weight (g)
per ear
136.5
Rio Grande and
Western Pueblos
Havasupai and
Navajo
32/365
2.6
15.0
150.1
390.6
10/143
3.2
13.9
116.1
371.5
24/331
2.8
12.1
68.1
190.7
13/157
2.6
11.6
70.1
182.3
3/45
8/129
3.3
3.5
11.9
12.9
63.1
74.1
208.2
259.4
39/446
2.4
13.6
107.3
250.3
30/350
2.7
13.6
111.4
300.8
9/96
2.5
13.5
99.5
248.8
18/151
1.8
15.4
124.9
224.8
Alpha group 2
Southern Arizona
and Northern
Mexico
Lower Colorado
Navajo, Apache,
Pueblo
Alpha group 3
Rio Grande and
Western Pueblos
Navajo, Mexico
Alpha group 4
Mean
Mean
number ear row
of ears
number
per plant
Estimated
mean
kernel
weight (g)
per plant
341.3
For perspective, two prior controlled U.S. Native American maize studies offer
comparative grain yield data for a Colorado Plateau maize (Zuni blue flour) and a Sonoran
Desert maize (Tohono O’odham (Papago) flour). A project to document Zuni blue flour maize
production systems of Zuni farmers in semi-arid northern New Mexico provided data on maize
grain yields for runoff agricultural systems typical of low-density crop production by subsistence
50
farmers (Muenchrath et al. 2002). This Zuni blue flour maize has been classified here into alpha
group 1 (plot 1043). A separate two-year field trial south of Albuquerque, New Mexico focused
on Tohono O’odham (Papago) “60-day” flour maize (Muenchrath 1995), which would fit into
alpha group 2. This second study included five separate irrigation treatments that ranged from
well-watered (every two weeks) to watered only at planting. In addition, detailed weather records
revealed that growing season precipitation was notably delayed during the second year of the
experiment (1993), providing insight into the effects that rainfall timing can have on grain yield
(Adams et al. 1999).
Variability in grain yield can be notable (Table 17). The Zuni study, based on a mean of
9,650 plants per hectare, reported 1.1 ears per plant and 66.7 g of grain per plant (Muenchrath et
al. 2002). Based on these figures, grain yield per ear averages 60.6 g. Under the optimal
irrigation conditions of the Farmington study reported here, the same maize accession produced
2.8 ears per plant and a mean grain yield of 126.7 g per ear in a close spacing of 14,642 plants
per hectare. This comparison suggests that grain yield estimates of alpha group 1 maize ears
under optimal irrigation may be at least twice those of maize ears grown under more normal and
average conditions of subsistence farming; the differences in mean grain yield per plant are over
five times higher for the irrigated maize reported here (Table 17).
Table 17. Summary of maize grain yields reported for three separate experimental studies.
Tohono O’odham: Treatment 1 watered every two weeks; Treatment 5 was watered only at
planting; in 1993 natural rainfall contributed little to maize plant development and maturation.
Maize
Study
No. of
plants
No. of
ears
Zuni blue flour
Zuni blue flour
Alpha group 2
Tohono O’odham
1992, Treatment 1
Tohono O’odham
1992, Treatment 5
Tohono O’odham
1993, Treatment 1
Tohono O’odham
1993, Treatment 5
Mean
ears per
plant
2.8
1.1
Mean
grain yield
per ear (g)
126.7
60.6
Mean
grain yield
per plant (g)
354.8
66.7
This study
Muenchrath
et al. 2002
5
14
This study
Adams et al.
1999
Adams et al.
1999
Adams et al.
1999
Adams et al.
1999
119
48
331
46
3.0
1.0
68.1
37.7
206.3
37.7
48
41
0.9
15.5
14.0
48
95
2.0
22.1
44.2
48
22
0.5
8.8
4.4
51
The yield differences for southern Arizona and northern Mexico maize are similarly
diminished. This study reports a mean number of 3.0 ears per plant, and a mean grain yield of
68.1 g per ear for alpha group 2 (Table 17). In contrast, the previous Tohono O’odham flour
maize study documented a range of grain yields that declined with lengthening intervals between
irrigation treatments, and that were lower during the second year (1993) due to both delayed
precipitation during the growing season and to predation by ear worms (Heliothis zea), rodents,
and birds (Adams et al. 1999; Muenchrath 1995). Those maize plants receiving water every two
weeks produced 1-2 ears per plant, 2-3 times lower grain yield per ear, and 5 times lower grain
yield per plant than the alpha group 2 plants of this study. Maize plants in the Tohono O’odham
study receiving water only at planting produced even fewer ears per plant (0.9-0.5), extremely
low grain yield per ear and per plant, and returns so low in 1993 as to produce little more than
kernels to plant in a future year.
These three studies together provide experimentally based data on the range of grain
yield values produced under optimal irrigation conditions (this study), under conditions of
subsistence farming (the Zuni study), and under conditions of varying moisture as applied
irrigation and normal precipitation (the Tohono O’odham study). Archaeologists now have data
on the range of maize grain yields possible by representatives of two distinctive Native American
alpha groups (1 and 2) defined in this study.
Ethnographic literature reports a desirable goal of producing an average of 160 kg of
maize kernels per person per year (Van West 1994: 125). To meet this goal, a hectare of maize in
the Zuni study would provide 3.6 individuals with their yearly maize requirement (Table 18).
Assuming a similar planting density (9,650 plants per hectare), a hectare of Tohono O’odham
flour maize watered every 2 weeks would feed 2-3 individuals annually. Under the optimal
irrigated conditions reported here, 9,650 alpha group 1 maize plants would feed 20.6 individuals.
The same number of alpha group 2 maize plants would feed 11.5 individuals. Under the sparsest
watering regime of the Tohono O’odham study, the maize produced would not even feed a single
individual. Examining the same data on a per acre basis (1 hectare = 2.47 acres), the number of
individuals fed for a year drops to: (a) 1.5 for the Zuni study; (b) 1 for the well-watered Tohono
O’odham maize; (c) 8.3 for the alpha group 1 maize of this study; and (d) 4.7 for the alpha group
2 maize of this study. Thus, an average family of six individuals would require 4 acres (Zuni), 6
acres (Tohono O’odham), 0.7 acres (alpha group 1), or 1.3 acres (alpha group 2) of successful
52
maize production to meet the desired 160 kg goal of maize kernels for each family member for
the year.
Table 18. Number of estimated people fed by a hectare of maize plants.
Study
Alpha group 1 (this study)
Alpha group 2 (this study)
Alpha group 3 (this study)
Alpha group 4 (this study
Zuni (Muenchrath et al. 2002)
Mean kg of
Estimated number of people
maize grain yield fed, each requiring 160 kg
per hectare
annually (Van West 1994).
3293*
20.6
1840*
11.5
2415*
15.1
2169*
13.6
572 (+- 181)
3.6 (2.5-4.7)
Tohono O’odham, Treatment 1
364*
2.3
1992 (Adams et al 1999)
Tohono O’odham, Treatment 5
135*
0.8
1992 (Adams et al 1999)
Tohono O’odham, Treatment 1
427*
2.7
1993 (Adams et al 1999)
Tohono O’odham, Treatment 5
43*
0.3
1993 (Adams et al 1999)
*Based on Tables 16 and 17, and assuming a density of 9,650 plants per hectare, as reported by
Muenchrath et al. (2002).
SUMMARY
Archaeologists and agronomists working together have developed a baseline of
descriptive data on ear characters and kernel traits of 123 Native American historic maize
accessions, including information relevant to archaeological subsistence models. A total of 1,436
fully formed maize ears that were all grown together under experimentally-controlled conditions
have provided comparative data on a number of maize plant developmental and ear/kernel
morphological traits. Because the experimental conditions were optimal (regular watering and
fertilizing), maximal trait expression has been assumed. This maize baseline, the first of its kind
in the Greater Southwest, provides a basis for characterizing the diversity of Native American
maize landraces grown historically.
Based on a number of ear and kernel observations, the 123 accessions have been
organized into a total of four alpha and 27 beta morphological groups, supported by a level of
statistical confidence. Three alpha groups segregate on the basis of overall ear size and shank
53
diameter (large, small, and medium), and a fourth group on the presence of a number of ear
characters and kernel traits normally associated with modern hybrid dent maize. The 27 beta
groups segregate on the basis of main kernel color and main kernel endosperm texture; some
combinations (e.g. blue flour) occur within more than one alpha group.
The distribution of the alpha and beta groups correlates with geographic and cultural
distributions of Native American groups. The majority of large ear flour maize accessions that
come in a diversity of colors (alpha group 1) were predominantly collected from the Rio Grande
and Western Pueblos. A few seem to have been shared with Havasupai and Navajo groups.
Many of the small ear maize accessions that are limited in color but include a diversity of kernel
endosperm types (alpha group 2) were provided by southern Arizona and northern Mexican
farmers of the Sonoran and Chihuahuan desert regions. Some of these accessions appear to have
been shared with groups living along the Lower Colorado River, and with Western Puebloan and
Navajo farmers. A large number of accessions with medium-sized ears that come in a diversity
of colors and endosperm types (alpha group 3) were being grown by Rio Grande and Western
Pueblo farmers, although some were also collected from geographically distant groups. Alpha
group 3, which is intermediate in its ear and kernel traits, may represent some level of cross
breeding between alpha groups 1 and 2. The final group of accessions includes ears with many
traits of modern hybrid dent maize (alpha group 4), suggesting Native American farmers also
grew maize that included modern hybrid dent germplasm.
To further test the validity of this morphological classification, the 27 morphological
groups can be examined via DNA analyses. Maize selected from the different alpha and beta
groups can be compared and contrasted for various genetic markers. Depending on results, it
might be possible to suggest the direction of movement or origin of some of the accessions,
and/or their developmental chronology, which is inevitably related to the movements of peoples.
Archaeologists modeling maize subsistence in the ancient record should find utility in the
environmental data and grain yield results of this study. For 86 accessions, the average number
of frost-free days from emergence (when seedlings become susceptible to frost) to maturity was
128 days, and the mean CGDD (Cumulative Growing Degree Day) heat units was 2,342.
Because some southern Arizona and northern Mexican accessions were not grown in their
normal lower desert region of adaptation, it is possible their environmental heat parameters are
not accurately estimated.
54
Maize grain yield can vary notably by morphological type of maize and by moisture
available during the growing season. In this study, maize collected from Rio Grande and Western
Pueblo farmers averaged 150.1 g of kernels per ear and 390.6 g of kernels per plant in
experimental fields with a density of 14,642 plants per hectare. Maize collected from southern
Arizona and northern Mexico farmers averaged 70.1 g of kernels per ear and 182.3 g of kernels
per plant. Assuming a lower planting density of 9,650 plants per hectare as reported for Zuni
subsistence farmers, the maize returns from a hectare of maize for the four alpha groups reported
here would provide 160 kg of maize per year to feed between 11 (alpha group 2) and 20 (alpha
group 1) individuals. In terms of acreage, one acre would feed between 8.3 (alpha group 1) and
4.7 (alpha group 2) individuals. For a family of six individuals, farmers would need between 0.7
(alpha group 1) and 1.3 (alpha group 2) acres of successful maize production per year.
For archaeologists interested in modeling maize grain yield, the grain yield estimates for
this study are considerably above yields produced under less than optimal moisture conditions. In
fields with a mean of 9,650 plants per hectare, Zuni traditional farmers produced an average of
572 kg of maize, each hectare estimated to feed nearly four individuals. A hectare of Tohono
O’odham maize plants irrigated every two weeks produced enough maize to feed between two
and three individuals, and plants that received no supplemental irrigation water and significantly
delayed precipitation produced only enough grain for future planting. In terms of acreage, an
acre of Zuni maize would feed 1.5 individuals annually, and Tohono O’odham maize watered
every two weeks would feed a single individual for a year, requiring 4 or 6 acres of maize,
respectively, for a family of six.
This study has described and grouped ears of Native American maize accessions grown
under identical experimental conditions simulating intensively irrigated agriculture on the
Colorado Plateau. Clear-cut differences exist between distinctive alpha morphological groups,
which are further distinguished into beta subgroups on the basis of kernel color and endosperm
type. Future studies could include growing all or a representative selection of these accessions in
other distinctive ecogeographic regions, such as the Sonoran and Chihuahuan Deserts.
Depending on plant performance in arid and hot locations, changes in CGDD values and days to
maturity may vary for those accessions tolerant of extreme heat. In addition, to better simulate
dry-land farming, water applications could be limited to the mean inches of water available
during the growing season or to traditional growing practices. Yield potential could be explored
55
under different planting regimens. Future experimental fields could be located where Native
American farmers have been known to grow maize, and the range of soil characters relevant to
agriculture documented. With such controlled experiments, valuable knowledge would be gained
regarding the adaptation of various maize accessions to the different geographic locations,
varying environments, and diverse soils that encompass the range of agricultural conditions
experienced by Native American subsistence farmers through the last four millennia.
To support their societies, the relative success of prehistoric peoples depended
significantly upon their ability to leverage differences in performance of their maize landraces.
For thousands of years, maize farmers optimized the expression of genetic and environmental
interaction(s) by continuously selecting for better-adapted, dependable, and productive maize.
This study has provided a snapshot of this process by describing and categorizing into 27
morphological groups a total of 123 historic maize accessions acquired from indigenous
southwestern U.S. and northern Mexican farmers. This informative baseline has potential
applications in multiple disciplines, beyond the relevance for archaeology explored here.
56
ACKNOWLEDGMENTS
MAÍS Southwest project personnel (Figure 15) thank the following individuals and institutions
for providing generous assistance and support for this interdisciplinary project:
Principal project personnel:
• Co-Principal Investigator Dr. Deborah A. Muenchrath and Master’s Student Lindsay Werth,
Iowa State University, Department of Agronomy, Ames, IA.
• Co-Principal Investigator Dr. Candice Gardner and Curator Mr. Mark Millard, USDA-ARS
North Central Plant Introduction Station and Iowa State University, Ames, IA.
• Superintendent Dr. Mick O’Neill, NMSU Agricultural Science Center, Farmington, NM.
Funding:
• Dr. Henry L. Shands, U. S. Department of Agriculture, Agricultural Research Service, for the
basic grant to accomplish the field grow-outs.
• James S. McDonnell Foundation 21st Century Research Award/Studying Complex Systems,
Grant No. 21002035, provided by Dr. Ann Kinzig, School of Life Sciences and Global
Institute for Sustainability, Arizona State University, Tempe, AZ.
• Preparing Future Faculty Emeriti Fellowship Committee, Division of Graduate Studies,
Arizona State University grant to Cathryn M. Meegan.
• Sigma Xi, Arizona State University Chapter grant to Cathryn M. Meegan.
• Arizona State Museum Raymond H. Thompson Endowment grant to Ryan Howell.
Field Preparation and Data Collection at NMSU ASC-Farmington, NM site:
• 2004: Dr. Mick O’Neill, Rick Arnold, Dan Smeal, Curtis Owen, Ken Kohler, Tom Jim,
Kevin Lombard, Rob Heyduck, Margaret West, Zach Williams, Merlin Begay, Sandra
Brown-Polacca, Jamie Beam, Leandra Jones, Holly Akins, Linda Jones, Iris Garnanez and
Carleen Simpson.
• 2005: Dr. Mick O’Neill, Rick Arnold, Dan Smeal, Curtis Owen, Ken Kohler, Tom Jim,
Merlin Begay, Rob Heyduck, Margaret West, Nikki Pryor, Charlene Begay, Linda Jones,
Kyle O’Neill, Colby Hamilton and Max Labato.
Harvest Assistance in 2004 and 2005:
• Dr. Carolyn Lawrence, Dr. Candice Gardner, Dr. Ana Gulbani, Rob Heyduck, Dr. Deborah
Muenchrath, Jean Muenchrath, Ryan Peterson, Nickki Pryor, John Roney, Rudi Roney,
Trisha Rude, Gail Werth, Lindsay Werth, Margaret West, and other NMSU Agricultural
Science Center staff members.
• We also thank Dr. Mick O’Neill and Margaret West for providing us with living quarters
during the harvests, and the NMSU Agricultural Science Center staff for hosting barbecues
and for making us feel welcome. We thank Lindsay Werth for making the best pies west of
the Pecos.
57
Post-harvest assistance in 2004 and 2005:
• Rex Adams and the University of Arizona, Laboratory of Tree-Ring Research for providing
space to air dry the maize.
• Dr. Scott White of the University of Arizona, Department of Soil, Water, and Environmental
Science for making available the plant drying ovens.
• Student laboratory workers at Arizona State University, Tempe, AZ: Sidney Rempel, Tahnee
Williams, Eric LaPlante, Adrienne Aragon, Sarah Mapes, Destiny Crider, and Andrea
Moreno.
• Photography: Karen R. Adams, R. Emerson Howell, Cathryn M. Meegan, and Sidney
Rempel.
• Advice on approaches to future DNA analyses: Dr. John Doebley, Dr. Viviane Jaenicke
Despres, and Dr. Carolyn Lawrence.
Laboratory space for analysis and collection storage:
• Dr. Katherine Spielmann, School of Human Evolution and Social Change, Arizona State
University, Tempe, AZ.
• Dr. Glen Rice, Office of Cultural Resource Management, School of Human Evolution and
Social Change, Arizona State University, Tempe, AZ.
• Dr. Mark D. Varien, Crow Canyon Archaeological Center, Cortez, CO.
• Dr. Paul Fish and Dr. Suzanne K. Fish, Borderlands Laboratory, Arizona State Museum.
58
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59
Karen R. Adams
Lindsay Werth
Cathryn M. Meegan
Deborah Muenchrath
Scott G. Ortman
Mick O’Neill
R. Emerson Howell
Candice Gardner
Figure 15. Interdisciplinary MAÍS Southwest project personnel.
60
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Appendix 1. Field observations on 123 Native American maize accessions, organized by alpha and beta groups. ACP accessing
institutions include: PI (USDA Plant Introduction Station); NSL (National Seed Storage Laboratory); and AMES. A single accession
(Plot 1043) not yet accessioned represents Zuni blue flour maize reported by Muenchrath et al. (2002). In this appendix, the “planting”
date for all accessions is the “effective planting date” of May 21st (the first irrigation), when kernels first had access to soil moisture.
Since maturity dates were reported for accessions as a whole, no s.d. could be calculated for this particular field observation.
Final plant
SD days
Mean
Maturity
Mean
Native American group Number of Number of Mean SD
height (m)
from
number of
(black
ears
plants
ears ears number of
days from emergence to
layer
per days from
recorded recorded
per
maturity
emergence
date)
plant plant planting to
to maturity
maturity
New Mexico (Mesita)
19
5
4.0
1.4
144
12-Oct
137.0
1.0
2.8
Maize
alpha
group
Maize
beta
group
ACP
(accessing
institution)
Accession
number
2004,
Replicate 1
plot number
1
1
PI
218146
1018
1
1
PI
218153
1025
San Felipe
14
5
3.0
1.4
1
1
PI
218156
1028
Santo Domingo
13
5
2.6
1.1
146
14-Oct
138.3
0.6
2
3
1
1
PI
218157
1029
Santa Clara
15
5
3.0
1.2
136
4-Oct
128.0
1.7
2
1
1
n/a
n/a
1043
Zuni (Ojo Caliente)
14
5
2.8
0.8
130
28-Sep
122.7
0.6
n/a
1
1
PI
218164
1094
Navajo
13
5
2.6
1.1
137
5-Oct
127.7
1.5
2
1
1
PI
218175
1098
Hopi (Moencopi)
12
5
2.6
1.5
144
12-Oct
135.0
2.6
2.2
1
1
PI
311229
1115
Navajo
17
5
3.6
1.5
144
12-Oct
136.0
1
1
PI
420250
1122
Hopi
15
5
3.4
1.5
153
21-Oct
144.3
1
2
PI
218130
1003
Santo Domingo
11
5
2.4
1.5
1
2
PI
218133
1005
New Mexico (Mesita)
13
4
3.5
1.3
1
2
PI
218138
1010
Isleta
5
3
1.7
0.6
3
1
2
PI
218139
1011
Zia
9
4
2.5
1.3
2.5
1
2
PI
218159
1031
Zia
18
5
3.6
1.5
3.2
1
2
PI
218168
1033
Acoma
8
4
2.5
1.0
1
2
PI
218173
1038
Jemez
11
5
2.2
0.8
1
2
NSL
68332
1072
Hopi
10
5
3.0
1.0
130
28-Sep
123.0
1
2
PI
213738
1086
Navajo
8
5
1.6
0.9
130
28-Sep
122.3
0.6
1
2
PI
218176
1099
Hopi (Moencopi)
11
5
2.4
1.1
144
12-Oct
137.0
1.0
2.5
1
2
PI
317679
1119
Havasupai
13
5
3.0
2.0
141
9-Oct
131.7
2.5
1.75
1
3
PI
218144
1016
Isleta
12
5
2.4
1.1
141
9-Oct
133.3
0.6
3
1
3
PI
218147
1019
New Mexico (Mesita)
14
4
3.5
1.3
1
3
PI
218167
1032
Acoma
15
5
3.0
1.0
144
12-Oct
134.3
2.9
2.3
1
3
PI
218169
1034
Laguna
12
5
2.8
2.7
146
14-Oct
138.7
0.6
2.75
1
3
PI
218172
1037
Jemez
3
4
1.0
0.0
1.75
0.6
1.75
3
146
149
14-Oct
17-Oct
3.2
139.0
141.0
1.0
2
2.75
1.6
1.75
2.75
3.25
68
Maize
beta
group
ACP
(accessing
institution)
Accession
number
2004,
Replicate 1
plot number
1
3
PI
317678
1118
Final plant
SD days
Mean
Maturity
Mean
Native American group Number of Number of Mean SD
height (m)
from
number of
(black
ears
plants
ears ears number of
days from emergence to
layer
per days from
recorded recorded
per
maturity
emergence
date)
plant plant planting to
to maturity
maturity
Havasupai
20
5
4.8
3.1
129
27-Sep
120.0
1.7
1.6
1
4
PI
218135
1007
Picuris (not San Lorenzo)
3
1
4
PI
218148
1020
Isleta
17
5
3.4
0.9
3
1
4
PI
218158
1030
Zia
6
5
1.4
0.5
3
Maize
alpha
group
4
1.3
0.5
123
21-Sep
115.3
0.6
1.6
2.75
1
4
PI
218170
1035
Laguna
10
4
3.0
1.2
1
4
PI
218162
1092
Navajo
15
5
3.2
1.1
130
28-Sep
122.7
0.6
1.7
1
4
PI
317674
1116
Havasupai
16
5
4.0
0.7
138
6-Oct
130.0
1.0
1.75
1
4
PI
317675
1117
Havasupai
19
5
4.4
1.1
138
6-Oct
130.0
1.0
1.4
1
5
PI
218137
1009
Tesuque
9
5
1.8
0.8
129
27-Sep
121.3
0.6
2.2
1
5
PI
476868
1042
Taos
11
5
2.6
1.1
136
4-Oct
127.7
0.6
1
5
NSL
67053
1049
Hopi
14
5
2.8
1.3
1
5
NSL
68325
1066
Hopi
9
5
2.2
0.8
137
5-Oct
129.3
0.6
3
1
5
NSL
68326
1067
Hopi
14
6
2.8
1.3
144
12-Oct
135.0
1.7
2.75
1
5
NSL
68327
1068
Hopi
9
6
2.2
1.0
137
5-Oct
129.0
1.0
2.5
1
5
PI
218165
1095
Navajo
13
5
3.0
1.2
144
12-Oct
136.7
1.2
1.4
2
2.75
1
5
PI
218178
1101
Hopi (Moencopi)
9
5
1.8
0.4
144
12-Oct
135.0
2.0
2
1
5
PI
476870
1136
Havasupai
9
5
1.8
0.8
144
12-Oct
137.0
1.0
1.5
2
6
PI
213741
1089
Walapai
9
5
1.8
0.4
129
27-Sep
119.0
2.6
1.6
2
6
PI
218163
1093
Navajo
14
5
2.8
1.1
130
28-Sep
118.0
1.7
1.5
2
6
PI
218185
1108
Papago
23
5
4.8
1.6
129
27-Sep
121.3
0.6
2.75
2
6
PI
218187
1110
Mojave
15
5
3.4
1.5
129
27-Sep
122.0
2
6
PI
420251
1123
Pima-Papago
14
5
3.0
1.0
123
21-Sep
115.3
0.6
123
21-Sep
114.3
2.1
2
6
PI
451716
1124
Pima-Papago
11
5
2.2
1.3
2
6
PI
474206
1149
Mexico, Sonora
8
5
2.0
1.0
2
7
NSL
68323
1064
Hopi
19
5
4.2
0.8
2
7
PI
213740
1088
Navajo
16
5
3.8
1.8
2
7
PI
218186
1109
Mojave
21
5
4.8
2
7
PI
503563
1126
Pima-Papago
10
5
2
7
PI
503573
1132
Pima-Papago
11
5
2
7
NSL
2830
1148
Mexico, Sonora
8
5
1.6
0.5
2
8
Ames
22643
1001
Hopi
21
5
5.0
1.0
1.4
1.4
1.3
2.75
1.5
129
21-Sep
122.3
0.6
3.6
130
28-Sep
123.7
0.6
2.2
1.1
136
4-Oct
128.7
1.2
2
2.2
0.4
129
21-Sep
120.0
1.7
1.75
123
21-Sep
115.7
0.6
1.3
1.6
2
2
69
Final plant
SD days
Mean
Maturity
Mean
Native American group Number of Number of Mean SD
height (m)
from
number of
(black
ears
plants
ears ears number of
days from emergence to
layer
per days from
recorded recorded
per
maturity
emergence
date)
plant plant planting to
to maturity
maturity
Tesuque
12
4
3.3
1.0
144
12-Oct
135.3
0.6
2
Maize
alpha
group
Maize
beta
group
ACP
(accessing
institution)
Accession
number
2004,
Replicate 1
plot number
2
8
PI
218134
1006
2
8
PI
218174
1097
Hopi (Moencopi)
12
4
3.0
0.8
126
24-Sep
118.7
0.6
2
8
PI
420247
1120
Hopi
21
5
4.6
1.1
137
5-Oct
129.7
0.6
2
8
PI
490973
1158
Mexico, Sonora
9
5
2.0
1.0
2
9
PI
218140
1012
Acoma
14
5
3.0
1.6
137
5-Oct
128.3
0.6
2.75
2
9
PI
474209
1147
Mexico, Sonora (Warihio
& Mayo)
9
5
1.8
0.4
143
11-Oct
134.0
1.7
3
123
21-Sep
113.7
2.3
1.6
146
14-Oct
137.0
2
9
PI
484413
1150
Mexico, Chihuahua
8
5
2.0
0.7
2
10
PI
420245
1040
Mexico, Sinaloa
15
5
3.0
0.7
2
11
PI
213714
1076
Papago
14
6
3.0
1.1
1.4
1.3
3.25
3
3.25
2
12
PI
218179
1102
Papago
17
5
3.4
1.1
144
12-Oct
135.7
0.6
2.5
3
13
PI
218145
1017
New Mexico (Siles
Pueblo)
15
5
3.0
0.7
144
12-Oct
137.0
1.0
2.75
141
9-Oct
130.0
2.75
3
13
PI
218150
1022
Cochiti
10
5
2.0
0.7
3
13
PI
218151
1023
Cochiti
12
5
3.0
1.9
3
13
NSL
67054
1050
Hopi
13
5
2.6
1.1
141
9-Oct
133.7
0.6
3
3
13
NSL
67058
1054
Hopi
7
3
3.3
2.3
132
30-Sep
124.0
1.0
2.2
3
13
NSL
68329
1069
Hopi
8
5
2.4
0.9
3
13
PI
213729
1078
Apache
10
5
2.0
1.2
141
9-Oct
130.7
2.1
2.9
0.6
1.7
2.5
3
3
13
PI
213737
1085
Navajo
8
5
1.8
0.8
123
21-Sep
114.0
3
13
PI
218166
1096
Navajo
15
5
4.0
2.3
138
6-Oct
130.7
3
13
PI
503564
1127
Hopi (Bacabi)
9
5
2.0
138
6-Oct
130.0
3
13
PI
503568
1131
Pueblo
10
5
2.0
136
4-Oct
129.0
2
1.4
1.0
2
3
13
PI
476869
1135
Hopi
6
5
1.4
0.5
144
12-Oct
137.3
0.6
1.75
3
14
PI
218141
1013
Acoma
14
5
3.0
2.4
138
6-Oct
130.3
0.6
2.75
3
14
PI
218142
1014
Picuris (not San Lorenzo)
7
5
1.6
0.9
123
21-Sep
115.7
1.2
1.4
3
14
PI
218149
1021
Taos
11
5
2.4
1.7
136
4-Oct
128.3
0.6
1.75
3
14
PI
218188
1039
Zia
16
5
3.2
1.6
3
14
PI
485116
1143
Mexico, Chihuahua
10
5
2.2
0.4
130
28-Sep
123.0
3
15
PI
218131
1004
Cochiti
18
5
3.8
1.6
129
27-Sep
121.7
0.6
3
3
15
NSL
67064
1060
Hopi
5
3
1.7
0.6
144
12-Oct
137.3
0.6
2.5
3
2.2
70
Final plant
SD days
Mean
Maturity
Mean
Native American group Number of Number of Mean SD
height (m)
from
number of
(black
ears
plants
ears ears number of
days from emergence to
layer
per days from
recorded recorded
per
maturity
emergence
date)
plant plant planting to
to maturity
maturity
Hopi
18
5
3.6
1.7
136
4-Oct
127.0
1.7
1.75
Maize
alpha
group
Maize
beta
group
ACP
(accessing
institution)
3
15
NSL
68334
1073
3
15
PI
420248
1121
Hopi
13
4
3.5
3
15
PI
503565
1128
Hopi (Hotevilla)
10
5
2.0
3
15
PI
503567
1130
Hopi (Hotevilla)
12
5
2.4
1.3
3
16
PI
420252
1041
Pima-Papago
15
5
3.0
1.2
3
16
NSL
67066
1062
Hopi
8
6
2.0
0.9
138
6-Oct
130.0
3
16
NSL
68324
1065
Hopi
13
5
2.6
1.1
123
21-Sep
117.0
3
16
PI
484433
1152
Mexico, Chihuahua
11
5
2.2
0.4
141
9-Oct
3
17
PI
213739
1087
Navajo
6
5
1.8
0.8
136
3
18
PI
484482
1151
Mexico, Chihuahua
6
4
2.0
0.8
Accession
number
2004,
Replicate 1
plot number
1.7
1.6
153
21-Oct
144.0
2.0
136
4-Oct
128.7
0.6
2
130
28-Sep
123.3
0.6
1.5
3
1.0
1.8
133.3
0.6
2.75
4-Oct
127.3
0.6
2
137
5-Oct
129.3
0.6
2.75
1.4
3
19
PI
218136
1008
Tesuque
16
5
3.2
1.8
138
6-Oct
131.0
1.0
1.4
3
19
PI
218160
1090
Navajo
15
5
3.2
0.8
137
5-Oct
128.0
2.6
1.5
3
20
PI
503566
1129
Hopi (Hotevilla)
9
5
2.0
0.7
130
28-Sep
123.3
0.6
2
3
21
PI
218143
1015
Santo Domingo
18
5
3.8
0.8
3
21
NSL
68330
1070
Hopi
12
3
4.7
0.6
144
12-Oct
136.7
0.6
1.6
3
21
NSL
68331
1071
Hopi
14
5
3.2
1.1
144
136.3
0.6
2
3
21
PI
503562
1125
Hopi
10
6
1.8
0.4
144
12-Oct
136.7
0.6
2
3
22
PI
213733
1081
Hopi
11
5
2.4
1.1
136
4-Oct
129.0
1.0
1.5
3
23
NSL
67060
1056
Hopi
13
5
3.2
1.6
138
6-Oct
130.7
0.6
1.9
3
23
NSL
67065
1061
Hopi
12
5
2.6
1.7
141
9-Oct
133.7
1.2
2.75
4
24
NSL
67047
1044
Hopi
9
5
1.8
0.8
3
4
24
NSL
67048
1045
Hopi
10
4
2.5
0.6
3.3
4
24
NSL
67049
1046
Hopi
6
4
1.8
1.0
3.25
3.4
3
4
24
NSL
67051
1047
Hopi
11
5
2.6
1.7
4
24
NSL
68336
1075
Hopi
6
5
1.8
0.4
4
24
PI
213728
1077
Apache
12
4
3.3
1.0
4
24
PI
218181
1104
Papago
7
5
1.4
0.9
4
24
PI
218182
1105
Papago
7
4
1.8
1.0
3.2
4
24
PI
218183
1106
Papago
8
5
1.6
0.9
3.25
4
24
PI
218184
1107
Papago
4
5
1.6
0.5
3
4
24
PI
218190
1112
Papago
15
6
2.7
1.2
3
4
24
PI
218191
1113
Papago
5
4
1.5
0.6
3
3
138
6-Oct
129.3
0.6
2
3
71
Maize
alpha
group
Maize
beta
group
ACP
(accessing
institution)
Accession
number
2004,
Replicate 1
plot number
Final plant
SD days
Mean
Maturity
Mean
Native American group Number of Number of Mean SD
height (m)
from
number of
(black
ears
plants
ears ears number of
days from emergence to
layer
per days from
recorded recorded
per
maturity
emergence
date)
plant plant planting to
to maturity
maturity
Mexico, Coahuila
5
4
1.5
0.6
3.5
4
24
PI
629147
1144
4
25
PI
218154
1026
San Felipe
9
5
2.0
1.0
3
4
25
NSL
67052
1048
Hopi
9
5
1.8
0.4
2.75
4
26
NSL
67055
1051
Hopi
7
5
1.6
1.3
4
26
NSL
68335
1074
Hopi
14
5
2.8
0.8
4
27
PI
218171
1036
Jemez
7
5
1.4
0.5
130
28-Sep
121.3
2.1
2
2.75
146
14-Oct
139.0
2.75
72
Appendix 2. Ear characters of 123 Native American maize accessions, organized by alpha and beta groups.
Number of Mean SD
Maize Maize
2004,
ears
ears ears
alpha beta Replicate 1
per
recorded
per
group group
plot
plant plant
number
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
4
4
4
4
4
4
1018
1025
1028
1029
1043
1094
1098
1115
1122
1003
1005
1010
1011
1031
1033
1038
1072
1086
1099
1119
1016
1019
1032
1034
1037
1118
1007
1020
1030
1035
1092
1116
19
14
13
15
14
13
12
17
15
11
13
5
9
18
8
11
10
8
11
13
12
14
15
12
3
20
3
17
6
10
15
16
4.0
3.0
2.6
3.0
2.8
2.6
2.6
3.6
3.4
2.4
3.5
1.7
2.5
3.6
2.5
2.2
3.0
1.6
2.4
3.0
2.4
3.5
3.0
2.8
1.0
4.8
1.3
3.4
1.4
3.0
3.2
4.0
1.4
1.4
1.1
1.2
0.8
1.1
1.5
1.5
1.5
1.5
1.3
0.6
1.3
1.5
1.0
0.8
1.0
0.9
1.1
2.0
1.1
1.3
1.0
2.7
0.0
3.1
0.5
0.9
0.5
1.2
1.1
0.7
Ear size
category
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Shank size
category
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
large
Mean SD ear Mean
ear diam. shank
diam. (cm) diam.
(cm)
(cm)
4.4
3.3
4.0
4.2
3.8
4.2
4.0
4.0
3.9
4.3
4.5
5.1
4.3
4.3
4.0
4.2
4.1
3.9
4.5
3.9
4.6
4.5
4.9
4.2
5.0
3.9
4.2
4.6
4.1
3.9
4.2
4.3
0.4
0.2
0.5
0.4
0.2
0.2
0.2
0.4
0.2
0.7
0.3
0.4
0.5
0.4
0.3
0.4
0.4
0.3
0.5
0.3
0.5
0.4
0.3
0.7
0.1
0.4
0.2
0.3
0.4
0.3
0.2
0.2
2.1
2.2
1.2
1.4
1.8
2.1
1.9
1.7
1.5
2.0
2.3
2.7
2.3
1.9
2.6
2.5
2.0
2.2
1.8
2.3
2.4
2.6
2.6
1.8
2.5
2.3
2.3
2.3
1.8
1.7
2.2
3.3
SD
shank
diam.
(cm)
Mean
ear
weight
(g)
SD ear
weight
(g)
0.5
0.5
0.4
0.4
0.4
0.6
0.7
0.4
0.3
1.0
0.6
0.6
0.6
0.6
0.5
0.9
0.7
0.4
0.6
0.5
0.8
0.6
0.5
0.6
0.6
0.6
0.6
0.9
0.3
0.3
0.8
0.8
160.2
132.7
177.9
172.4
161.4
172.3
141.9
146.3
154.9
161.5
182.8
240.1
199.4
236.4
164.4
194.1
139.0
153.9
173.7
146.7
211.5
212.7
234.1
169.6
364.0
109.1
174.8
217.3
239.8
171.4
175.4
156.1
47.7
29.1
39.5
37.7
41.7
34.2
46.9
44.4
36.2
89.2
59.7
100.5
59.3
62.6
50.7
94.7
50.9
39.7
66.3
46.3
76.4
64.2
72.6
81.6
58.9
31.8
23.7
80.6
47.1
37.8
48.9
48.6
Estimated
mean
kernel
weight
per ear
(g)
125.7
104.1
139.6
135.3
126.7
135.2
111.4
114.8
121.6
126.8
143.5
188.4
156.5
185.5
129.0
152.3
109.1
120.8
136.3
115.1
166.0
166.9
183.7
133.1
285.6
85.6
137.2
170.5
188.2
134.5
137.7
122.5
SD estimated
mean
kernel
weight
per ear
(g)
37.4
22.8
31.0
29.6
32.7
26.8
36.8
34.8
28.4
70.0
46.9
78.9
46.5
49.1
39.8
74.3
40.0
31.2
52.1
36.3
60.0
50.4
57.0
64.0
46.3
25.0
18.6
63.2
37.0
29.7
38.4
38.2
Mean
ear
row #
SD
ear
row
#
16.8
12.1
17.4
15.2
14.7
15.1
15.8
14.8
12.8
18.5
16.8
18.4
15.3
14.9
15.3
14.9
13.6
14.5
13.5
12.8
18.0
16.0
13.6
13.5
16.7
11.9
14.7
16.1
13.3
13.4
14.9
13.6
2.1
1.5
2.5
1.3
2.4
1.6
2.0
1.4
1.5
2.8
1.7
3.0
2.2
3.0
2.4
1.6
2.1
2.3
1.3
1.0
2.4
2.7
1.7
2.1
1.2
1.9
1.2
1.8
1.6
1.6
2.6
1.4
Mean SD ear Ratio of
length
ear
ear
length (cm) diameter
to ear
(cm)
length
18.8
21.6
21.2
22.6
20.7
20.5
20.0
19.3
22.3
18.6
21.9
21.1
20.6
24.8
21.9
23.3
19.0
23.6
19.0
19.5
19.8
20.9
23.6
22.3
27.3
17.1
21.8
21.4
27.9
24.4
20.6
21.2
3.7
3.7
3.9
4.0
4.8
3.5
2.4
4.7
3.6
5.2
6.1
6.0
5.9
4.5
3.0
6.7
3.7
2.8
4.7
4.2
5.6
4.2
4.2
4.3
2.7
3.8
3.8
5.0
4.8
2.3
4.8
4.0
0.23
0.15
0.19
0.19
0.18
0.20
0.20
0.21
0.18
0.23
0.21
0.24
0.21
0.17
0.18
0.18
0.21
0.17
0.24
0.20
0.23
0.21
0.21
0.19
0.18
0.23
0.19
0.21
0.15
0.16
0.21
0.20
73
Number of Mean SD
Maize Maize
2004,
ears
ears ears
alpha beta Replicate 1
per
recorded
per
group group
plot
plant plant
number
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
4
5
5
5
5
5
5
5
5
5
6
6
6
6
6
6
6
7
7
7
7
7
7
8
8
8
8
8
9
9
9
10
11
12
1117
1009
1042
1049
1066
1067
1068
1095
1101
1136
1089
1093
1108
1110
1123
1124
1149
1064
1088
1109
1126
1132
1148
1001
1006
1097
1120
1158
1012
1147
1150
1040
1076
1102
19
9
11
14
9
14
9
13
9
9
9
14
23
15
14
11
8
19
16
21
10
11
8
21
12
12
21
9
14
9
8
15
14
17
4.4
1.8
2.6
2.8
2.2
2.8
2.2
3.0
1.8
1.8
1.8
2.8
4.8
3.4
3.0
2.2
2.0
4.2
3.8
4.8
2.2
2.2
1.6
5.0
3.3
3.0
4.6
2.0
3.0
1.8
2.0
3.0
3.0
3.4
1.1
0.8
1.1
1.3
0.8
1.3
1.0
1.2
0.4
0.8
0.4
1.1
1.6
1.5
1.0
1.3
1.0
0.8
1.8
3.6
1.1
0.4
0.5
1.0
1.0
0.8
1.1
1.0
1.6
0.4
0.7
0.7
1.1
1.1
Ear size
category
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Small
Shank size
category
large
large
large
large
large
large
large
large
large
large
small
small
small
small
small
small
small
small
small
small
small
small
small
small
small
small
small
small
small
small
small
small
small
small
Mean SD ear Mean
ear diam. shank
diam. (cm) diam.
(cm)
(cm)
3.7
3.9
3.8
4.0
4.3
4.2
4.2
3.9
4.7
4.7
3.6
3.8
3.1
3.5
2.9
3.2
3.9
3.2
2.9
3.3
3.3
3.2
3.2
3.1
4.4
3.3
3.6
3.4
3.1
3.3
3.2
3.0
3.4
3.4
0.2
0.2
0.4
0.3
0.3
0.1
0.3
0.5
0.4
0.3
0.2
0.2
0.3
0.2
0.1
0.4
0.4
0.4
0.1
0.3
0.4
0.2
0.4
0.3
0.2
0.2
0.3
0.3
0.2
0.3
0.2
0.4
0.3
0.2
1.7
2.5
1.8
1.8
2.2
1.8
2.5
2.2
2.4
1.9
1.1
1.7
1.5
1.2
1.3
1.3
1.6
1.0
1.1
1.5
1.6
1.2
0.9
1.1
1.7
1.4
1.4
1.2
1.4
0.8
1.1
1.0
1.3
1.3
SD
shank
diam.
(cm)
Mean
ear
weight
(g)
SD ear
weight
(g)
0.3
0.6
0.3
0.5
0.6
0.7
0.7
0.7
0.8
0.6
0.2
0.3
0.2
0.2
0.2
0.2
0.3
0.5
0.2
0.3
0.6
0.4
0.2
0.3
0.4
0.3
0.2
0.3
0.3
0.3
0.4
0.2
0.2
0.2
98.9
178.9
180.6
178.4
206.9
170.3
176.1
133.6
243.0
187.3
74.0
135.1
73.2
90.8
65.4
105.7
125.0
77.4
53.4
76.3
109.8
89.0
97.5
63.0
147.8
74.0
87.1
78.6
104.3
88.1
80.0
53.0
92.3
102.9
34.5
44.3
50.8
60.5
58.5
46.3
61.2
54.1
69.5
48.6
25.2
33.3
24.7
23.3
9.0
24.5
43.1
26.1
15.7
34.0
38.2
28.8
44.8
21.1
34.4
25.6
22.9
22.3
27.0
19.7
28.1
18.7
36.6
20.6
Estimated
mean
kernel
weight
per ear
(g)
77.6
140.4
141.7
140.0
162.4
133.7
138.2
104.9
190.7
147.0
58.1
106.0
57.4
71.3
51.3
82.9
98.1
60.8
41.9
59.8
86.1
69.9
76.5
49.4
116.0
58.1
68.3
61.7
81.8
69.2
62.8
41.6
72.4
80.8
SD estimated
mean
kernel
weight
per ear
(g)
27.1
34.8
39.9
47.5
45.9
36.4
48.0
42.4
54.5
38.1
19.7
26.1
19.4
18.3
7.1
19.2
33.8
20.5
12.3
26.7
30.0
22.6
35.2
16.6
27.0
20.1
18.0
17.5
21.2
15.4
22.1
14.7
28.7
16.2
Mean
ear
row #
SD
ear
row
#
12.9
14.0
13.3
14.3
14.0
15.3
14.3
13.4
13.6
15.6
12.7
14.1
10.7
11.2
10.9
13.3
11.0
11.3
8.3
11.7
12.0
11.6
8.3
11.8
14.8
13.0
14.4
11.6
14.6
13.6
11.5
12.7
12.4
11.6
1.5
2.0
2.9
1.5
1.7
2.3
2.3
1.9
1.7
2.2
1.0
1.5
1.5
1.3
1.3
1.0
1.9
1.7
0.7
2.1
0.9
1.5
0.7
0.9
1.3
1.6
1.9
1.7
1.8
1.7
0.9
1.0
0.9
1.9
Mean SD ear Ratio of
length
ear
ear
length (cm) diameter
to ear
(cm)
length
16.5
22.1
22.5
21.7
22.8
20.2
22.6
19.5
23.2
20.0
15.3
19.9
16.5
17.9
14.9
18.0
20.4
15.8
15.0
15.8
20.0
18.3
21.8
13.7
17.6
12.8
14.9
17.5
17.8
20.0
16.0
13.1
16.8
17.5
3.6
4.6
3.5
4.5
4.3
5.0
5.3
5.4
5.9
3.9
2.0
2.7
3.5
2.7
1.8
2.5
3.5
2.7
3.1
3.5
3.3
2.9
4.1
2.9
2.8
2.5
2.4
1.6
3.2
2.6
3.6
1.4
4.8
2.3
0.22
0.18
0.17
0.18
0.19
0.21
0.18
0.20
0.20
0.23
0.23
0.19
0.19
0.20
0.20
0.18
0.19
0.20
0.19
0.21
0.16
0.17
0.15
0.23
0.25
0.26
0.24
0.20
0.18
0.17
0.20
0.23
0.20
0.19
74
Number of Mean SD
Maize Maize
2004,
ears
ears ears
alpha beta Replicate 1
per
recorded
per
group group
plot
plant plant
number
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
13
13
13
13
13
13
13
13
13
13
13
13
14
14
14
14
14
15
15
15
15
15
15
16
16
16
16
17
18
19
19
20
21
21
1017
1022
1023
1050
1054
1069
1078
1085
1096
1127
1131
1135
1013
1014
1021
1039
1143
1004
1060
1073
1121
1128
1130
1041
1062
1065
1152
1087
1151
1008
1090
1129
1015
1070
15
10
12
13
7
8
10
8
15
9
10
6
14
7
11
16
10
18
5
18
13
10
12
15
8
13
11
6
6
16
15
9
18
12
3.0
2.0
3.0
2.6
3.3
2.4
2.0
1.8
4.0
2.0
2.0
1.4
3.0
1.6
2.4
3.2
2.2
3.8
1.7
3.6
3.5
2.0
2.4
3.0
2.0
2.6
2.2
1.8
2.0
3.2
3.2
2.0
3.8
4.7
0.7
0.7
1.9
1.1
2.3
0.9
1.2
0.8
2.3
0.5
2.4
0.9
1.7
1.6
0.4
1.6
0.6
1.7
1.7
1.3
1.2
0.9
1.1
0.4
0.8
0.8
1.8
0.8
0.7
0.8
0.6
Ear size
category
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Shank size
category
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
medium
Mean SD ear Mean
ear diam. shank
diam. (cm) diam.
(cm)
(cm)
3.8
4.0
3.9
3.9
3.5
4.1
4.0
3.8
3.7
3.9
3.6
3.8
4.1
4.4
4.1
3.8
3.6
4.0
4.3
3.8
3.4
3.8
3.9
4.0
4.0
3.8
3.9
4.0
3.9
4.0
3.9
3.6
3.7
4.2
0.3
0.4
0.4
0.2
0.4
0.3
0.3
0.2
0.3
0.4
0.3
0.2
0.2
0.3
0.5
0.4
0.4
0.5
0.4
0.3
0.5
0.3
0.2
0.4
0.4
0.3
0.2
0.4
0.2
0.3
0.2
0.2
0.2
0.3
2.1
1.1
1.4
1.6
1.3
0.9
1.2
2.0
1.4
2.3
1.6
1.8
1.9
1.8
1.3
1.2
1.5
2.2
1.6
1.9
1.3
1.4
1.7
1.0
1.1
1.4
1.2
1.8
1.2
1.4
1.5
1.4
1.6
1.7
SD
shank
diam.
(cm)
Mean
ear
weight
(g)
SD ear
weight
(g)
0.4
0.5
0.4
0.6
0.5
0.4
0.3
0.2
0.3
0.6
0.4
0.2
0.8
0.2
0.4
0.2
0.6
0.5
0.2
0.3
0.5
0.3
0.5
0.3
0.4
0.5
0.2
0.5
0.2
0.5
0.4
0.2
0.5
0.4
183.9
137.4
178.3
151.9
110.5
120.6
107.6
123.2
122.0
150.6
132.2
136.0
180.4
158.6
164.7
134.1
163.9
150.1
178.4
110.1
104.2
138.2
145.5
74.6
189.3
100.3
155.6
121.9
131.1
122.8
122.2
132.6
122.1
129.6
32.8
40.2
67.0
33.2
42.7
26.0
32.0
27.6
35.5
38.7
43.3
31.7
42.8
40.3
53.0
52.1
35.3
48.4
68.0
30.8
67.2
42.4
42.3
40.7
73.2
30.6
40.4
39.2
18.9
27.8
35.4
30.0
36.6
39.8
Estimated
mean
kernel
weight
per ear
(g)
144.3
107.8
139.9
119.2
86.7
94.7
84.5
96.7
95.8
118.2
103.8
106.7
141.5
124.5
129.3
105.3
128.6
117.8
140.0
86.4
81.8
108.5
114.2
58.6
148.6
78.7
122.1
95.7
102.9
96.4
95.9
104.1
95.8
101.7
SD estimated
mean
kernel
weight
per ear
(g)
25.8
31.5
52.6
26.1
33.5
20.4
25.1
21.7
27.8
30.4
33.9
24.9
33.6
31.7
41.6
40.9
27.7
38.0
53.4
24.2
52.7
33.3
33.2
32.0
57.5
24.0
31.7
30.8
14.8
21.8
27.8
23.6
28.7
31.3
Mean
ear
row #
SD
ear
row
#
15.7
13.8
16.4
14.3
13.4
11.8
14.0
12.0
13.3
15.3
13.6
13.7
13.0
13.3
13.5
12.3
13.6
13.8
13.2
12.6
13.8
13.2
12.3
15.2
12.8
12.8
12.4
15.3
12.7
14.1
13.5
13.6
15.1
14.0
2.7
2.0
2.7
2.8
2.2
0.7
1.7
1.1
2.0
1.4
2.1
2.0
1.7
1.6
1.6
1.9
2.3
3.1
2.7
0.9
1.5
1.4
1.2
3.5
1.8
1.3
1.2
2.1
1.0
2.1
0.9
1.3
1.4
2.4
Mean SD ear Ratio of
length
ear
ear
length (cm) diameter
to ear
(cm)
length
22.5
19.2
20.6
20.7
17.0
17.6
18.2
17.9
18.1
19.7
19.0
19.1
18.9
19.0
19.4
19.0
23.1
18.2
20.3
17.7
17.2
19.9
20.4
15.3
23.1
17.2
18.5
16.0
16.8
17.2
19.3
21.2
19.2
19.3
2.8
5.8
4.6
2.5
3.3
2.1
2.8
4.3
3.8
4.1
4.1
4.3
3.4
1.9
4.2
3.8
3.8
3.6
4.5
3.0
5.4
4.1
2.9
2.0
5.0
3.2
3.6
3.9
3.1
2.3
4.4
4.8
3.9
3.9
0.17
0.21
0.19
0.19
0.21
0.23
0.22
0.21
0.21
0.20
0.19
0.20
0.22
0.23
0.21
0.20
0.16
0.22
0.21
0.21
0.20
0.19
0.19
0.26
0.17
0.22
0.21
0.25
0.23
0.23
0.20
0.17
0.19
0.22
75
SD
shank
diam.
(cm)
Mean
ear
weight
(g)
SD ear
weight
(g)
Mean SD ear Ratio of
length
ear
ear
length (cm) diameter
to ear
(cm)
length
SD estimated
mean
kernel
weight
per ear
(g)
27.3
31.9
22.7
40.2
28.1
40.6
Mean
ear
row #
SD
ear
row
#
14.8
13.2
13.6
11.4
14.0
14.9
1.8
2.1
1.7
2.4
2.1
1.5
19.3
20.3
18.4
18.6
19.9
15.5
3.5
4.6
2.9
3.7
3.0
3.4
0.20
0.18
0.19
0.22
0.20
0.32
3
3
3
3
3
4
21
21
22
23
23
24
1071
1125
1081
1056
1061
1044
14
10
11
13
12
9
3.2
1.8
2.4
3.2
2.6
1.8
1.1
0.4
1.1
1.6
1.7
0.8
Medium
Medium
Medium
Medium
Medium
Unspecified,
dent
medium
medium
medium
medium
medium
unspecified
4.0
3.7
3.5
4.0
3.9
4.9
0.3
0.3
0.2
0.4
0.3
0.3
1.8
2.1
1.9
1.5
1.5
1.1
0.6
0.5
0.6
0.5
0.3
0.3
134.9
131.4
120.4
159.8
151.1
127.2
34.8
40.6
29.0
51.2
35.8
51.8
Estimated
mean
kernel
weight
per ear
(g)
105.9
103.1
94.5
125.4
118.6
99.9
4
24
1045
10
2.5
0.6
Unspecified,
dent
unspecified
5.2
0.6
1.7
0.3
138.2
56.5
108.5
44.3
16.4
2.1
15.0
2.2
0.34
4
24
1046
6
1.8
1.0
Unspecified,
dent
unspecified
5.2
0.4
1.6
0.4
129.8
60.3
101.8
47.4
17.0
2.4
16.3
3.4
0.32
4
24
1047
11
2.6
1.7
Unspecified,
dent
unspecified
4.8
0.3
1.3
0.4
157.8
35.2
123.9
27.6
16.5
2.2
17.7
2.1
0.27
4
24
1075
6
1.8
0.4
Unspecified,
dent
unspecified
4.5
0.4
1.2
0.3
97.5
44.5
76.5
34.9
13.3
1.6
13.6
3.5
0.33
4
24
1077
12
3.3
1.0
Unspecified,
dent
unspecified
4.4
0.2
1.0
0.2
173.3
33.9
136.0
26.6
15.5
1.2
17.6
1.9
0.25
4
24
1104
7
1.4
0.9
Unspecified,
dent
unspecified
4.9
0.3
1.5
0.1
173.4
30.2
136.1
23.7
14.9
1.1
16.6
2.8
0.30
4
24
1105
7
1.8
1.0
Unspecified,
dent
unspecified
4.9
0.2
1.4
0.2
158.5
57.8
124.4
45.4
14.6
1.5
16.9
2.2
0.29
4
24
1106
8
1.6
0.9
Unspecified,
dent
unspecified
4.6
0.5
1.4
0.2
130.6
49.9
102.5
39.1
15.8
2.9
17.3
3.3
0.26
4
24
1107
4
1.6
0.5
Unspecified,
dent
unspecified
5.2
0.5
2.0
0.3
160.1
56.6
125.6
44.5
16.5
1.9
18.5
3.8
0.28
4
24
1112
15
2.7
1.2
Unspecified,
dent
unspecified
4.4
0.5
1.3
0.7
118.1
67.4
92.7
52.9
14.9
1.7
13.9
4.9
0.32
4
24
1113
5
1.5
0.6
Unspecified,
dent
unspecified
5.2
0.3
1.5
0.3
192.2
91.2
150.9
71.6
15.6
2.2
18.9
3.7
0.28
4
24
1144
5
1.5
0.6
Unspecified,
dent
unspecified
4.1
0.4
1.1
0.3
103.1
40.6
80.9
31.8
14.4
1.7
18.3
2.1
0.22
4
25
1026
9
2.0
1.0
Unspecified,
dent
unspecified
4.9
0.4
1.9
0.6
267.4
83.0
209.8
65.1
16.0
1.7
23.2
4.2
0.21
4
25
1048
9
1.8
0.4
Unspecified,
dent
unspecified
4.9
0.2
1.4
0.4
200.9
39.2
157.7
30.7
14.2
0.7
17.1
2.9
0.29
Number of Mean SD
Maize Maize
2004,
ears
ears ears
alpha beta Replicate 1
per
recorded
per
group group
plot
plant plant
number
Ear size
category
Shank size
category
Mean SD ear Mean
ear diam. shank
diam. (cm) diam.
(cm)
(cm)
76
SD
shank
diam.
(cm)
Mean
ear
weight
(g)
SD ear
weight
(g)
Mean SD ear Ratio of
length
ear
ear
length (cm) diameter
to ear
(cm)
length
SD estimated
mean
kernel
weight
per ear
(g)
60.4
Mean
ear
row #
SD
ear
row
#
15.7
2.1
15.1
4.7
0.32
4
26
1051
7
1.6
1.3
Unspecified,
dent
unspecified
4.9
0.4
1.4
0.3
151.3
76.9
Estimated
mean
kernel
weight
per ear
(g)
118.7
4
26
1074
14
2.8
0.8
Unspecified,
dent
unspecified
4.6
0.3
2.1
0.3
132.5
48.9
104.0
38.4
15.7
2.6
14.9
2.7
0.31
4
27
1036
7
1.4
0.5
Unspecified,
dent
unspecified
5.1
0.4
2.7
0.8
275.7
93.7
216.3
73.5
14.9
2.0
22.6
4.7
0.23
Number of Mean SD
Maize Maize
2004,
ears
ears ears
alpha beta Replicate 1
per
recorded
per
group group
plot
plant plant
number
Ear size
category
Shank size
category
Mean SD ear Mean
ear diam. shank
diam. (cm) diam.
(cm)
(cm)
77
Appendix 3. Kernel traits of 123 Native American maize accessions, organized by alpha and beta groups.
Maize
alpha
group
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Number Main kernel color % ears % ears % ears % ears
Maize
2004,
with
with
with
and endosperm
with
beta Replicate of ears
brown
recorded
description
pointe streaked blue
group
1 plot
kernels kernels kernels
d
number
kernels
1
1018
19
blue flour
94.74
84.2
1
1025
14
“
14.3
50.00
92.9
1
1028
13
“
53.85
100.0
1
1029
15
“
66.7
1
1043
14
“
57.1
35.71
71.4
1
1094
13
“
38.5
38.46
69.2
1
1098
12
“
91.7
33.33
100.0
1
1115
17
“
100.0
100.0
1
1122
15
“
80.0
2
1003
11
white or white and
9.1
9.09
red flour
2
1005
13
“
38.46
2
1010
5
“
40.00
2
1011
9
“
55.56
2
1031
18
“
5.6
2
1033
8
“
37.50
2
1038
11
“
45.5
45.45
2
1072
10
“
50.0
50.00
2
1086
8
“
75.0
87.50
2
1099
11
“
45.5
45.45
2
1119
13
“
53.8
3
1016
12
orange flour
8.3
8.33
3
1019
14
“
3
1032
15
“
20.0
20.00
3
1034
12
“
16.7
16.67
3
1037
3
“
33.3
33.33
3
1118
20
“
45.0
4
1007
3
mixed color flour
66.67
4
1020
17
“
41.18
41.2
4
1030
6
“
16.7
16.7
4
1035
10
“
10.0
40.00
40.0
4
1092
15
“
46.7
40.00
53.3
4
1116
16
“
93.8
% ears
with
multicolored
kernels
5.3
% ears % ears
with
with
orange pink
kernels kernels
% ears
with
purpleblack
kernels
% ears
with
red
kernels
% ears
with
white
kernels
% ears % ears % ears % ears % ears % ears
with
with
with
with
with
with
sweet
pop
flour
flint
dent
yellow
kernels kernels kernels kernels kernels kernels
10.5
7.1
7.1
33.3
28.6
15.4
15.4
7.1
7.7
16.7
20.0
9.1
90.9
100.0
100.0
100.0
100.0
87.5
9.1
30.8
91.7
85.7
100.0
100.0
66.7
100.0
12.5
90.9
100.0
75.0
100.0
69.2
8.3
14.3
33.3
33.3
47.1
11.8
33.3
56.3
25.0
50.0
40.0
20.0
26.7
25.0
66.7
11.8
20.0
18.8
6.7
100.0
92.9
100.0
100.0
92.9
92.3
83.3
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
88.2
100.0
100.0
93.3
100.0
78
Maize
alpha
group
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
Number Main kernel color % ears % ears % blue % ears
Maize
2004,
kernels with
with
and endosperm
with
beta Replicate of ears
brown
recorded
description
pointe streaked
group
1 plot
kernels
kernels
d
number
kernels
4
1117
19
mixed color flour 47.4
52.6
5
1009
9
mixed color flour
55.56
or flint
5
1042
11
“
9.1
36.36
72.7
5
1049
14
“
7.1
28.57
5
1066
9
“
5
1067
14
“
50.00
5
1068
9
“
11.1
66.67
33.3
5
1095
13
“
69.2
46.15
46.2
5
1101
9
“
44.4
77.78
5
1136
9
“
100.00
6
1089
9
white flour
66.7
11.1
6
1093
14
“
28.6
21.43
6
1108
23
“
21.7
30.43
6
1110
15
“
6.7
6
1123
14
“
6
1124
11
“
6
1149
8
“
50.00
7
1064
19
white flint or flour
5.26
2
2
2
2
2
2
2
2
2
2
2
7
7
7
7
7
8
8
8
8
8
9
1088
1109
1126
1132
1148
1001
1006
1097
1120
1158
1012
16
21
10
11
8
21
12
12
21
9
14
2
2
2
9
9
10
1147
1150
1040
9
8
15
“
“
“
“
“
white sweet
“
“
“
“
white, yellow or
pink flint or pop
“
“
brown pop or flint
2
11
1076
14
yellow flour
% ears
with
multicolored
kernels
11.1
% ears % ears
with
with
orange pink
kernels kernels
% ears
with
white
kernels
% ears % ears % ears % ears % ears % ears
with
with
with
with
with
with
sweet
pop
flour
flint
dent
yellow
kernels kernels kernels kernels kernels kernels
77.8
27.3
7.1
22.2
7.7
44.4
64.3
33.3
50.0
11.1
46.2
11.1
11.1
27.27
12.50
47.62
25.00
83.33
61.90
21.43
11.1
45.5
28.6
44.4
35.7
28.6
66.7
50.0
33.3
88.9
44.4
88.9
64.3
100.0
100.0
78.6
81.8
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
42.9
76.2
33.3
100.0
% ears
with
red
kernels
47.4
11.1
50.00
16.7
% ears
with
purple/
black
kernels
50.0
75.00
62.5
56.3
38.1
10.0
27.3
75.0
43.8
61.9
90.0
54.5
12.5
35.7
17.4
20.0
57.1
100.0
50.0
73.3
57.9
54.5
71.4
44.4
64.3
100.0
61.5
66.7
100.0
100.0
100.0
82.6
80.0
100.0
90.9
100.0
42.1
38.5
11.1
21.4
18.2
37.5
100.00
100.0
100.0
88.9
9.1
11.1
22.2
18.2
12.5
22.2
21.4
11.1
78.6
11.1
37.5
33.3
88.9
62.5
66.7
100.0
100.0
100.0
100.0
100.0
66.7
79
Maize
alpha
group
2
Number Main kernel color % ears % ears % blue % ears
Maize
2004,
kernels with
with
and endosperm
with
beta Replicate of ears
brown
recorded
description
pointe streaked
group
1 plot
kernels
kernels
d
number
kernels
12
1102
17
mixed color flour
23.5
17.65
5.9
or flint
3
13
1017
15
mixed color flour
or flint
“
“
“
“
“
“
“
“
“
“
“
yellow flint or pop
3
3
3
3
3
3
3
3
3
3
3
3
13
13
13
13
13
13
13
13
13
13
13
14
1022
1023
1050
1054
1069
1078
1085
1096
1127
1131
1135
1013
10
12
13
7
8
10
8
15
9
10
6
14
3
3
3
3
3
14
14
14
14
15
1014
1021
1039
1143
1004
7
11
16
10
18
“
“
“
“
white or white and
red flour
3
3
3
3
3
3
15
15
15
15
15
16
1060
1073
1121
1128
1130
1041
5
18
13
10
12
15
“
“
“
“
“
white flour or flint
3
3
3
3
16
16
16
17
1062
1065
1152
1087
8
13
11
6
3
18
1151
6
“
“
“
yellow flint or
flour
purpleblack or blue
pop, flint or flour
3
19
1008
16
yellow flour
71.4
75.0
20.0
12.5
53.3
73.33
40.0
60.00
50.00
30.77
100.00
37.50
30.00
12.50
60.00
10.0
50.0
25.0
60.0
% ears
with
multicolored
kernels
% ears % ears
with
with
orange pink
kernels kernels
25.0
60.0
16.7
84.6
42.86
9.09
50.00
10.00
11.11
6.7
20.0
8.3
7.7
14.3
25.0
25.0
7.7
27.3
33.3
25.0
22.2
33.3
10.0
83.3
33.3
7.7
10.0
5.9
82.4
13.3
86.7
8.3
30.8
100.0
12.5
20.0
25.0
23.1
12.5
10.0
40.0
22.2
60.0
85.7
64.3
28.6
71.4
81.8
93.8
100.0
100.0
100.0
100.0
100.0
91.7
69.2
87.5
80.0
75.0
100.0
77.8
40.0
100.0
14.3
21.4
100.0
100.0
100.0
100.0
61.1
92.3
90.0
100.0
100.0
100.0
100.0
100.0
90.0
100.0
10.0
100.0
100.0
100.0
100.0
9.1
100.0
33.3
17.6
70.0
9.1
5.6
% ears % ears % ears % ears % ears % ears
with
with
with
with
with
with
sweet
pop
flour
flint
dent
yellow
kernels kernels kernels kernels kernels kernels
20.0
16.7
14.3
75.00
7.69
63.64
33.33
31.25
62.5
6.7
22.2
30.0
12.5
26.7
6.3
100.00
16.67
30.77
40.00
33.33
50.00
70.0
16.7
61.5
85.7
37.5
100.0
37.5
% ears
with
white
kernels
33.3
20.0
26.7
9.1
% ears
with
red
kernels
88.2
22.2
80.00
100.00
% ears
with
purple/
black
kernels
66.7
100.0
37.5
30.8
27.3
66.7
62.5
69.2
45.5
33.3
33.3
16.7
100.0
18.2
50.0
80
Maize
alpha
group
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Number Main kernel color % ears % ears % blue % ears
Maize
2004,
kernels with
with
and endosperm
with
beta Replicate of ears
brown
recorded
description
pointe streaked
group
1 plot
kernels
kernels
d
number
kernels
19
1090
15
yellow flour
6.7
20.00
20
1129
9
purpleblack flour
55.56
21
1015
18
blue flour
44.44
94.4
21
1070
12
“
91.7
50.00
100.0
21
1071
14
“
64.3
21.43
100.0
21
1125
10
“
80.0
22
1081
11
red flint
54.5
36.36
18.2
23
1056
13
mixed color flint
76.9
76.92
30.8
23
1061
12
”
50.0
8.3
24
1044
9
white dent
24
1045
10
“
20.0
24
1046
6
“
24
1047
11
“
24
1075
6
“
50.0
24
1077
12
“
50.0
25.00
24
1104
7
“
28.6
24
1105
7
“
14.3
24
1106
8
“
37.5
25.00
24
1107
4
“
24
1112
15
“
73.3
6.67
24
1113
5
“
40.0
24
1144
5
“
60.0
25
1026
9
yellow dent
44.44
25
1048
9
“
11.1
44.44
26
1051
7
mixed color dent
100.00
26
1074
14
“
42.9
21.43
27
1036
7
orange or yellow
85.7
dent, flint, or flour
% ears
with
multicolored
kernels
% ears % ears
with
with
orange pink
kernels kernels
% ears
with
purple/
black
kernels
% ears
with
red
kernels
% ears
with
white
kernels
% ears % ears % ears % ears % ears % ears
with
with
with
with
with
with
sweet
pop
flour
flint
dent
yellow
kernels kernels kernels kernels kernels kernels
100.0
100.0
5.6
8.3
20.0
81.8
23.1
58.3
16.7
35.7
71.4
46.2
33.3
100.0
100.0
100.0
100.0
16.7
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
28.6
64.3
90.9
100.0
100.0
66.7
100.0
100.0
71.4
28.6
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
88.9
100.0
100.0
71.4
100.0
100.0
100.0
91.7
100.0
100.0
9.1
11.1
14.3
14.3
81