performance of sweetpotato varieties in the caprivi, okavango and

performance of sweetpotato varieties in the caprivi, okavango and

IN THECAPRIVI,
VARIETIES
OF SWEETPOTATO
PERFORMANCE
REGIONS
AND OHANGWENA
OKAVANGO
BIANCARUSCH
Namibia
Windhoek,
PrivateBag13'184,
Research
Agronomy
Division
WaterandRuralDevelopment,
Ministryof Agriculture,
ABSTRACT
Twenty-fivesweetpotatovarietieswere evaluatedat Mashare
AgriculturalDevelopmentInstituteand Sachinga,Baganiand
MaheneneResearchStationsduringthe 1997/98season.The
season was characterizedby low and erratic rainfall,which
started late in the season. Resultsobtainedunder these
conditionsallowed evaluationof drought toleranceof the
differentvarieties expressed in terms of yield potentialand
maturity.Varietieswith high yield potentialand early maturity
o e r f o r m e d b e s t u n d e r t h e c o n d i t i o n so f e r r a t i c a n d
unpredictablerainfall.Advancedvarietyevaluationshouldbe
repeated for more growing seasons. Planting materialsof
the besfperformingvarietieswill be multipliedand shouldbe
evaluatedby farmers in collaborationwith FarmingSystems
Researchunits or the DirectorateExtensionand Engineering
Services.
INTRODUCTION
Encouragingresults obtained previouslyfrom sweetpotato
varietyevaluations(Lenhardt& Rusch,1996;Rusch' 1997)'
high interest shown by farmers and further support by the
SouthernAfrican Root Crops ResearchNetwork(SARRNET)
through the Namibian Root Crops Research Project led to
planning and approval of further evaluationof sweetpotato
varietiesduringthe 1997/98season. Entriesfor the advanced
evaluationtrialswere the elevenvarietiesthat performedbest
i n t h e p r e l i m i n a r yv a r i e t ye v a l u a t i o n sd u r i n gt h e 1 9 9 6 / 9 7
season. The 1997/98seasonwas characterizedby relatively
low and erraticrainfallthat started late'
DevelAgricultural
at Mashare
trialinspection
Figure1. Sweetpotato
oomentInstitute.
The trial layoutwas a randomizedcompleteblockdesignwiih
andtwo 3.3mrowsper blockin the preliminary
threereplications
and four 4.5m rows per block in the advancedtrials (Carey&
Reynoso, 1996). Cuttingswere spaced at 0.30m between
plantsand 1.2mbetweenrows. Onlytip cuttingswere usedfor
trial purposes. In the Kavangoand Caprivi regionsthe trials
were grownunderdrylandconditionswith vines plantedon the
flat. The trialat MaheneneResearchStationwas irrigatedand
heaped.Rainfallat Mashare,Baganiand Sachingaduringthe
1997/98growingseasonis shown in Table1. lrrigationwas
appliedat MashareADI shortlyafter plantingand in April to
save the trial from the severedrought.
Bagani
lnstitute,
Development
at MashareAgricultural
Table1.Rainfall
Stationduringthe 1997/9B
Research
StationandSachinga
Research
season
METHOD
lnitialevaluationof nineteenintroducedimprovedsweetpotato
varietieswith one localcheckwas repeatedin a preliminary
varietyevaluationtrial at BaganiResearchStation.The trial
w a s p l a n t e do n ' 1 6J a n u a r Y1 9 9 8 .
'14
Advancedvarietyevaluationtrialswere plantedon January
1998 at MashareAgriculturalDevelopmentInstitute(ADl) in
t h e K a v a n g or e g i o n ( F i g u r e 1 ) , o n 1 5 J a n u a r y 1 9 9 8 a t
SachingaResearchStationin the Capriviregionand on 20
J a n u a r y 1 9 9 8 a t M a h e n e n e R e s e a r c hS t a t i o n i n t h e
Ohangwenaregion.The trial entriesconsistedof the eleven
varietiesselectedfrom the preliminaryvariety
best-performing
and one ortwo locallycollected
1996197
during
trials
evaluation
varietiesas checks. Variety names and origin are shown in
AnnexA.
70
The grey area indicatesthe rain
Beforeplanting,2:3:2 (22) fertilizerwas broadcastat 200 kg/
ha and at MaheneneResearchStationa side dressingof125
kg/ha LAN was appliedsix weeks after planting(Soenarjo,
1995). Trialswere harvestedapproximatelyfour monthsafier
plantingon 12 May 1998 at SachingaResearchStation,13
May 1998at BaganiResearchStation(Figure2), 18 May 1998
AGRICOLA2OOO
The yield of the varietiesshown in Table3 was at a relatively
low level in terms of sweetpotatoproductionalthoughit is
c o m p a r a b l et o l o c a l l yo b s e r v e dp e a r l m i l l e t y i e l d s . T h e
previousselectionof SP2013,SP2017and SP2007Aas bestperformingvarietieswas confirmedby the results. SP2006
showed good performanceunder dryland conditionsand
shouldbe includedin the 1998i99advancedvarietyevaluation
trials. The mass per plant producedby SP2003was one of
the highest,yieldwas howeverstronglydecreasedby the high
proportionof crackedtubers.
varieties
Table2. Drymattercontentof sweetpotato
evaluated
during
the 1997/98
seasonat BaganiResearch
Station
Variety
Dry mass(%) Variety
SP2OOTA
sP2016
35.3"
sP2002
34.6 ub
sP201
8
sP201
0
sP2014
34.3 abc
33.4 abc
33.4 abc
sP2009
sP2003
sP2006
sP2019
SP2OOTB
32.8 b"
sP201
3
28.2 d
27.3 d.
26.8 d"
26.0 "t
24.3'e
sP2017
2 4 . 0s
2 2 . 9s
.ttb
F
t55.945
0.007
P
sP2001
32.6"
lvlean
CV
zY.l
SE
Dry mass(%)
0.001
a,b'c'd'e,r'svalues
with differentsuperscriptsdiffersignificantly
Figure2. Sweetpotato
trialharvestat BaganiResearch
Station.
at MashareADI and 8 June 1998 at MaheneneResearch
Station. For the advancedtrialsonly the two rniddlerows of
each plot were harvestedfor data recording. Data were
analyzedby using SigmaStatANOVAand MS Excel.In the
preliminaryvariety evaluationtrial the varieties SP2004,
SP2012,SP2015and the localcheckSP1006did not produce
any tubersand were left out of the analysis. The tuber dry
matter content was determinedafter harvest using a drying
was calculatedfrom the numberof
oven. The establishment
cuttings that were alive fourteen days after planting.
Marketabletubers were those that were more than 3 cm in
diameter at the thickest place. Yield was calculated by
proportionwith the mass
multiplication
of the establishment
per ha calculatedfrom massper plantand furthermultiplication
with the proportionmarketablemassfrom whichthe proportion
crackedtuber mass was subtracted.
RESULTSAND DISCUSSION
Figure3. Sweetpotato
tastetestingat BaganiResearch
Station.
1.
Preliminary sweetpotato variety evaluation trial
2.
Althoughthe trial receivedonly 194.5mm of rainafterplanting,
varieties.
a smallharvestwas possiblefor the best-performing
The taste of varieties with high dry matter content is often
most popular.
AGRICOLA2OOO
Advanced sweet potato variety evaluation trials
Yieldperformanceis only shownfor MaheneneResearchStation as sweetpotatovarietyevaluationswere performedat this
stationfor the first time duringthe 1997/98season.
71
Table3. performanceof sixteensweetpotatovarietiesin the
Variety
sP2013
sP2017
SP2OOTA
sP2006
sP2016
sP2019
sP2010
sP2009
sP2003
sP2001
sP2008
sP2018
sP2011
SP2OOTB
sP2014
(o/o)
Fetahlishment
vI.zn
100.00
95.80 "b
93.10 "b"
80.60 b"
100.00"
87.50 ub"
76.40"
Mean
CV
SE
91.58
5.400
0.014
F
5. /OC
46.56
0.074 b"
0.072 b'
0.087 b"
0.063 b"
0.080 b"
98.50 "
0.00
2.258
2.O25
87.50 "b
1.96
1.630
82.40 .b
85.30 "b
94.80 "
17.50
0.00
1.452
1.211
41.49
83.80 uo
10.71
0.00
0.00
0.00
20.83
1.186
0.806
98.50 "
96.30 "
92.00"
81.20 ^b
0.050 b"
0.028
0.085
32.84
0.012
7.545
0.001
Totalmass MarketableCrackedmass Yeld
perplant(kg) mass(%) perplant(kg) (Uha)
21.016
0.00
95
0.794 "
sP2017
'b
19.379
0.00
94
sP2009 0.748
"b
17.975
0.01
97
sP2019 0.678
"b"
1
7.129
0.00
92
sP2013 0.669
"b"d
1
1.906
0
.
0
0
92
sP2018 0.471
ub"d
11.817
0.00
87
SP2OOTA 0.491
10.947
0.00
81
sP2002 0.487 "o'o
abd
9.083
0.07
93
sP2003 0.429
b"d
8.314
0.02
89
sP2010 0.363
b"d
6.116
0.07
97
0.301
sP2011
"d
5.713
0.03
92
0.253
sP2012
d
1.207
0.02
85
0.075
Local
Variety
0.477
91
Q.021
SE
0.040
25.78
0.01
0.006
5.54
5.799 H *
53.91
75,79
19.828
<0.001
0.048
<0.001
11.717
*TheH statisticis usedfoTANOVAon Ranksanalysiswhen data is not
which
normallydistributed.Valuesshownfor varietiesare medianson
tfre anatysis is based instead of means' Different letters indicate
significantlYdifferentvalues
",ui,avalues
withina columndiffersignificantly
withdifferentsuperscripts
Resu|tsshowninTab|e4indicatethatthevarietiesperforming
the top
best in the Kavango and Caprivi region were also
by
Evaluations
Station'
Research
performers at l\4ahenene
resulted
iurt"r" duringa farmer'sday heldafterharvesting
of
yield,
marketability
on
based
in selectionof fourvarieties
yield'
highest
the
with
Varieties
(Figure
3).
tubersandtaste
72
7 1 . 1 0'
88.86
5.449
0.728
0.685
0.661
0.614
36.11
11.43
0.581
12.77
1.607
0.461
3.913
in the
Table4. Performanceof twelvesweetpotatovarietiesevaluated
StaResearch
Mahenene
at
1997/98
trial
evaluation
variety
advanced
tion.
Mean
90.40"
3.695
0.013
0.001
P
", va[res wth differentsuperscriptswithina columndiffersignificantly
CV
F
P
3.939
?782
9 1. 1 0 "
0.027'
0.038"
95.80 "b
77.80 b"
3.99
13'68
0.00
9 1. 7 0 ^
0.034
97.20 "b
84.60 "b
92.5U
0.180 "b
u.u45
0.027 "
98.60 "
Yield (Uha)
Mass Cracked (%)
Marketable Mass (%)
0 . 1 9 9"
91.70 ub"
98.60 "
Mass per Plant (kg)
0 . 1 8 1" b
0.183 "b
94.40 "o
80.60 b"
sP2002
station
1997/98preliminaryvarietyevaluationtrial at BaganiResearch
0.001
acceptabletaste and leastcrackedor misformedtuberswere
i d e n t i f i e da s S P 2 0 1 7 ,S P 2 0 0 2 , S P 2 0 0 9 a n d S P 2 0 0 7 A '
AlthoughSP2018and SP2019showedhighyields,theirround
tubershapewas seenas less marketablethan the longitudinal
shapes. SP2013was not taken into considerationbecauseit
yield
had a virus infection.Table5 shows sweetpotatovariety
potentialin terms of tuber formationand maturitywhich could
be well evaluatedduring the 1997/98 season with the low
rainfallat Mashareand SachingaResearchStations'
Potentialyield of the'evaluatedvarietieswas measured by
the total number of tubers initiated. The potentialfor early
maturity was reflected in the proportion marketabletubers
shown in Table 5. Varietiesthat could produce a relatively
high proportionof marketabletubers from plantingin mid
Lanuarythroughto the'last rains in mid April were perceived
as early maturing.Earlymaturingvarietieswith high potential
haveshownthe highestyieldsduringthe 1997/98rainyseason
(Figure4).
-A
1600/0
g
B
8.0
.C
' l3=;
soi;"
3 3 & : x f xf iF
ffi&
mnfuffieffi
g- *-
&Kl ffi | 4.0E E
l3it
ffilffil
l #l f f i l , r . o P E
Wl-l&ll
q
E
{
g
e
P
;
6.6
9
EilE8E*,.T,
N
d
N
c
d
0
&
a
Frgwe 4 Comparisonof percentagemarketabletubers at Mashare
StaAgriculturalDevelopmentInstitute(A) and MaheneneResearch
Agricultural
plant
Mashare
at
tion (B) and total numberof tubers per
(D) of ten
Developmentlnstitute(C) and MaheneneResearchStation
season'
sweetpotatovarietiesevaluatedduringthe 1997/98
AGRICOLA2OOO
Table5. Totalnumberof tubersper plantand proportionmarketabletubersharvestedfrom advancedsweetpotatovarietyevaluationtrialsduring
1997198at MaheneneResearchStation,MashareAgriculturalDevelopmentInstituteand SachingaResearchStation
Variety
2002 LM 88.014
2003 JaponTS
20074 XushuA
2009 Tts 2534
2010Tts 3290
Total number of tubers per plant
Mahenene
Mashare
Sachinga
6.896 "
3 . 1 6 7^
1.192
2.480 d"l
6.617 .b
4.450 b"d
cde
0.357 "f
4.064 "b
0.444
1.107
0.864
2.674 bcd
'l
.$$Q oet
201'l Naveto
1.696 "f
0.6241
0.940
0.000
20'13Blesbok
2017 Kudu
4.959 abc
3.202 abc
0.889
6.664 ub
4.076 "d
6.696 "b
1 . 1 5 0f
4.192.
1.383
0.610
2018 Mafutha
2019 Ribbok
Local1**
Local2**
Mean
SE
CV
3.251
2.948
abcd
Marketabletubers (%)
Mahenene
Mashare
Sachinga
44.3
59.2 b"
3
53.'l
99.4
17
43.1
62.0 b"
13
54.0
76.8 abc
0
oz.o
74.7
53.5
64.2
60.0
2.385 cde
1.218
0.723 r
0.905 "'
0.000
0.000
4.191
2.236
u . 3/ 5
14.21
u:z35
21.97
24.216
<0.001
0.799
0.107
U.U;l5
33.36
22.59
55.947
<0.001
1.244
r.35V
F (H- for Sachinga)
28.281
P
<0.001
6'1.9
50.7
59.1
56.8
o.322
b"
b"
b"
ub
b"
63.1 b"
58.7 b"
64.9
72.6
71.0
80.0
71.9
53.3"
69.4
0.022
10.69
5.779
<0.00'1
J
0
x
0
10
U
0
6.4
0.017
103.64
54.U66
<0.001
. The H statisticis usedfoTANOVAon Ranksanalysiswhen data is not normallydistributed.Valuesshownfor varietiesare medianson whichthe
analysisis based insteadof means.
* SPl010 at Mahenene,SP1005at Mashare,SP1016at Sachinga
*" SP2012at Mahenene,SP1003at Mashare,SP'1024at Sachinga
ANNEXA
RECOMMENDATIONS
It is recommended that, due to the unusuallylow rainfallduring
the 1997/98 season, advanced variety evaluation is repeated
in the 1998/99 season to consolidate the findings. Planting
materials of the best-performing varieties will be multiplied
and should be evaluated by farmers in collaboration with
Farming Systems Research units orthe Directorate Extension
and Engineering Services.
REFERENCES
procedures
CAREY E.E. & D.M. REYNOSO.1996.Recommended
for the evaluationof pathogen-tested sweet potatoclonesfrom
ClP. C/PResearchGuide 6, ClP, Lima, Peru.
LENHARDT,P.J. & B. RUSCH. 1996. The NamibianRoot Crops
ResearchProject:Sweetpotatoand cassavaresearchin northern
Namibia. MAWRD DARTAnnual ProgressReporf 1995/96.
RUSCH, B. 1997. The NamibianRoot Crops ResearchProject:
Evaluationof SweetPotatoCultivarsin the Okavangoand Caprivi.
MAWRD DARTAnnual ProgressReport 1996197.
SOENARJO,R. 1995.Betterculturalpracticesfor cassavaand sweet
polato. Luapula Regional Research Station, Mansa, Zambia.
AGRICOLA2OOO
Sweetpotatovariety names and origin
Variety
Origin
sP 2001
sP 2002
sP 2003
sP 2004
sP 2005
sP 2006
Name
LM 88.002
LMBB.O14
JaoonTresmesinoSelecto
Camote Yuca
Zapallo
Yan Shu '1
SP 2OO7A Xushu1B A
SF 2OO7B
sP 2008 l m b y3 1 0 2
ctP
ctP
Peru
Peru
Peru
sP 2009
s P2 0 1 0
sP 2011
sP2012
sP 20't3
sP 2014
s P 2 0 15
sP 2016
sP2017
sP2018
sP2019
sP 1001
sP 1003
sP 1005
sP 1006
sP1010
sP'1012
sP1016
sP 1024
Tts 2634
Tts 3290
Naveto
Chingovwa
Blesbok
Borrie
Bosbok
Brondal
Koedoe
Mafutha
Ribbok
Oshana
Kavandja
Shinguru
Shinguru
Ogongo
Epalela
Kanjoro
Choto
China
China
Unknown
Burundi
IITA
IITA
PapuaNew Guinea
Zambia
SouthAfrica
South Africa
SouthAfrica
SouthAfrica
South Africa
South Africa
SouthAfrica
Oshana
Caprivi (Shadikongoro
Caprivi
Caprivi (Bagani)
Oshana
Omusati(Epalela)
Caprivi(Mpacha)
Caprivi
73