B E E R E S E A R C H

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V.XXI
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DECEMBER
COMPARISON OF DIFFERENT VARIETIES OF TETRAPLOID
CLOVER. I~LUENCE OF THE INHIBITOR ALAR-85 ON
EFFECTIVE CLOVER POLLINATION BY BEES
S
1977
RED
Ta d e u s z W a w r y n
Pszczela Wola, Poland
Tetraploid red clover produces a high green mass crop but a very
low seed yield. The aim of the experiment was to determine the amount
of seed crop produced by some varieties of tetraploid clover as well as
to define their nutritional value for bees.
The experiment was modified by employing an inhibitor of growth
Alar 85. The coUaboration of Prof. H u l e w i c z - Ł ę c z y s k ą induced me to examine the effects of Alar 85 on the morphology of tetraploid
clover flower, its nectaring and the utilization of bees in its pollination.
The experiment began in 1974. On April 10, 14 varieties of tetraploid
clover were sown on plots 1 m wide and 5 m Iong. The elover came
from different countries: 3 varieties came from Poland, 3 from GDR,
2 subspecies were Swiss, 2 Danish, 1 Dutch, 1 Norwegian and 1 Hungarian. The experiment was carried out 3 times in Pszczela Wola, on
B elass deached soil on a former vegetable plot. Germination fell on the
first of May, and increase in flowering: in the second half of August.
The atmospheric conditions were favourable for the vegetation (the summer was wet.): there were 13 elear calm days with a maximum temperature of 5°C and seven cold days with occasional showers. The elover
spread out.
Measurements were recorded, from 17 August to 6 Septemper. For
20 consecutive days flowers were isolated, one at a time of each variety.
Every three days the length of 2h flower tubes and the nectar height
ń
were defined in groups of 10 f.lowers; the height of the nectar was
measured with a slider. 200 flowers from each variety were examined
(total 2800 flowers).
Prom the 23nd August for 13 eonsecutive days the visitation of all
varieties of clover by bees, bumble bees and other insects was studied.
The clover harvesting was done on the 15th September: threshing was
done by hand. The seed yield of particular varieties was defined and the
weight of 1000 seeds and the number of flowers per 1 m2 determined.
In 1976 similar measurements on the first and second crops were
reeorded. One hundred flowers from each variety (1400 flowers) from
each crop were examined for 10 days from the 7th to the 17th J uly
(first crop) and from the 22nd July to the 2nd August (second erop).
Additionally, on the 15th July 1975 varieties of clover at the stage
of buttonization were sprayed with 1% Alar 85. The lenght of the
tubes and the nectar height in 100 flowers of each variety was recorded.
On the whole, in 1975 3300 clover flowers were examined.
In 1976, again, measurements were made on 2 erops using 1 and 2%
solution of Alar 85. The experiment was implemented by setting up
frames with enclosed bees on 3 plots 15 m2 each. One plot was treated
with 1%, another with 2% solution, the third was a control ground.
RESULTS
The length of flower tubes. Particular varieties grown in different
years and the those obtained from the first and seeond erops had different flower tube lengths (table 1). In 1974 the average for all varieties
being 8,9 mm. The maximum length of individual flowers reached 11,6
mm. In 1976 the tube lengths varied among the subspecies. In the first
crop it ranged from 8,7 to 10,3 mm, 9,5 mm being the averagę and in
the second crop from 8,6 to 9,7 mm, the average 9,2 mm. The HungaTable
Comparison of different varieties of red tetraploid clover
Figures stand for averagę of 1400 flowers of 14 varieties
Difference
between I
and second
1975
feature
examined
1974
I crop
tube length in mm
distance to nectar in mm
nectar height in mm
nectar accessibillty for
honey bees below 6,8%
206
8,9
7,3
1,6
9,5
7,9
1,6
30,3
14,6
I
II crop
9,2
8,1
1,1
12
crop
-0,3
+0,2
-0,5
-2,6
1976
I crop
I
II crop
l
rian variety and the variety "Skrzeszowice Tetra" turned out to have
the shortest tubes whereas the Duteh variety and "tetri Dania" had,
the longest.
Quantity of nectar. The nectar eontent depended on weather counditions and varied from species to species. The quantity of nectar ranged
from 0,8 to 1,9 m, the average nectar height being 1,6 mm. In 1975 the
nectar height ran from 1,3 to 1,8 mm in the first erop, the averagę
height being 1,6 mm, and the corresponding figures for the second
erop were: 0,7-1,4 mm and 1,1 mm respictively. The distanee from
the topof the flower tube to the nectar, then in 1974 was on an average
7,3 mm for all varieties, and in 1975 was 7,8 mm for the first erop and
8,1 mm for the seeond erop. The shortest distance to the nectar was in
the Hungarian and "Skrzeszowice" varieties, the longest in the "Danish
Tetri", "Tripo Norway" and "Red Head Holland" varieties.
For each group of 100 flowers of eaeh variety the pereentage of flowers with distance to the nectar of less than 6,8 mm (aecessible to Caucasian bee hybrids) was defined with nectar aceessibility. Nectar accessibility is subject to varfation, varying both with species and years. In 1974
it ranged from 12 to 49010on an averagę 33010, in 1975 from 2 to 33010
with an averagę of 14010 on the first erop and from 1 to 31010, with an
average of 12% on the second crop. The varieties with the easiest nectar
accessibility for bees were: Hungarian: 49010, 33010 and 23010 "Skrzeszowice", B67/7 GDR, "Grodkowice", "Tripo Norway" and "Red Head
Holland" showed least accessibility.
Number of flowers. The number of flower s per 1 m? varied with
years and species. In 1974 it renged from 8 to 335. The record of 335
flowers was beaten by the Swedish variety "PeIly"; the fewest flowers
were observed in the "Tripo Norway" (8), "Skrzeszowice" (62) and
. "Hera Denmark" (80). The averagę number of flowers for aIl species
was 162. A very much greater quantity of flowers was observed in
1975, from 630 to 1592, depending on the type of clover, the averagę
number being 952. The record was beaten by "Skrzeszowice", which
hardly bloomed 'at all in the previous year. 5 varieties had over 1000
flowers per 1 m2: "Skrzeszowice" 1592, "Pelly Sweden" i 1359 (record
breaker in 1974), "W W Rea Sweden": 1333, "Hera Denmark": 1332 and
"Tripo Norway": 1039. The last two hardlły bloomed at al'lin 1974.
Surprisingly, a quite small number of flowers was observed in 1975
on seeond erop. It renged from 208 to 550, the averagę being 382 flowers, barely 400/0 of the first crop figure,. despite favoureble weather
conditions.
The quantity of flowers per 1 m2 is elosely connected with .the
height of elover seed yield. The correlation between the number of
flowers and the amount of seed crop was very high, its coefficient (r)
being 0,8 and the coo!fieient or regression reaching 0,008. Thismeans
207
Comparison
of quantity
of flowers in different
varieties
of tetraploid
Table
clover
2
Number ot nowers per l m3
Variety
I
1974
1975 I crop
1975 II crop
388
353
398
411
208
398
303
441
550
312
374
374
472
348
Grodkowice
Pelly Szwecja
B 67/7 NRD
Perenta NRD
II'ripo Norwegia
Red Head Holandia
Hera Dania
Tetri Dania
NT l NRD
MSG Tetri Holandia
WW Rea Szwecja
Jubilatka
Hungary Pelly Węgry
Skrzeszowicka
158
335
162
212
8
138
80
150
162
160
202
183
208
862
779
1359
871
731
1039
726
1332
636
847
758
1333
651
684
1592
Averaga
162
952
382 (40%)
Table
Comparison
Variety
of red clover seed yield in relation
1974
~
1975
I crop
kig
1975
II crop
kg
Total
kjg
Difference
between I and II
crop in 1975
k!g
Grodkowice
Pelly Szwecja
B 67/7 NRD
Perenta NRD
Tripo Norwegia
Red Head Holandia
Hera Dania
Tetri Dania
MT l NRD
MSG Tetri Holandia
WW Rea Szwecja
Jubilatka
Hungary Pelly
Skrzeszowieka
162
238
152
178
Averaga
208
3
to 1 ha
66
18
44
110
110
164
68
174
28
520
714
437
444
278
348
629
295
377
295
561
350
383
634
82
144
102
190
43
198
103
221
280
105
116
103
283
120
764
1092
691
812
321
612
750
560
767
510
841
521
840
782
108
448
149
782
I
%
-438
-570
-335
-254
-235
-200
-526
74
97
-140
-445
-247
-100
-514
15,8
20,1
23,3
42,8
15,5
56,9
16,3
74,9
74,2
35,6
20,7
29,4
73,9
18,9
-514
18,9
that every increase by 100 flowers per 1 m:2heightened the seed erop
by 16 kg per 1 heetare.
Cłover seed yields. The clovers varied eonsiderably in respeet of the
size of seed erop (table 3). In 1974 it ran from O to 238 kg/ha, the averag e being 108 kg/ha. The highest crop was obtained from "Pelly Sweden": 238 kg/ha, "Hungarian": 174 kg/ha, "WWRea Sweden" 164 kg/ha
"Perenta GDR": 178 kg and "Grodkowice": 162 kg.
In 1975 the amount of the first erop ran from 295 to 714 kg/ha, on
averagę 448 kg/ha. Onee again, the record went to "Pe11y Sweden"
744 kg, "Skrzeszowice" 634 kg, "Hera Denmark" 629 kg, "WW Rea
Sweden";: 561 kg/ha (a11 of them flowered abundantly), and "Grodkowice" 520 kg/ha.
The size of the seeond seed erop for a11 species ranged from 43 to
283 kg/ha, on average 149 kg. The size of the seeond erop was lower by
64% than the first erop.
The global quantity of the 3 erops obtained in 1974 and 1975 for
the different varieties was as fo11ows.The highest seed yield was obtained from "Pelly Sweden": 1092 kg/ha, "Hungarian": 840 kg/ha, "Perenta
GDR": 812 kg/ha, "Skrzeszowice":
782 kg/ha,
WW Sweden":
841 kg, "MT 1 GDR": 762 kg, "Grodkowice": 764 kg and "Hera Denmark": 750 kg/ha.
The lowest yields were obtained from "Tripo Norway", ""MSG tetri
Holland" and "Jubilat'ka". The highest yield crop aft er the first erop
was observed in "Pelly Sweden" 570 kg/ha, "Hera Denmark": 526 kg,
"Skrzeszowice": 514 kg/ha, and "Grodkowice": 438 kg.
The choice of the appropriate variety of tetraploid clover is closely
eonneeted with green-mass yield. The varieties with the highest seed
erop had a eorrespondingly high green-rnass yield. At the Centrę of
seed growing at Ulhówek the following green-mass erop per heetare was
obtained: "WWRea": 122 000 kg, The "Hungarian": 87800 kg, "Grodkowice": 85 500 kg, "Perenta GDR": 84500 kg, "Pelly Sweden": 86 500 kg.
There were varieties, however, which produced a high green-mass
yield though their seed crop was markedly low, ego "Tripo Norway":
90800 kg, "Jubilatka": 89 100 kg/ha.
Visitation of clover by bees and other insects. An apiary with about
80 colonieś of the Caucasian hybrid bees managed to fully pollinate the
clover. The number of bees on erop per 100 m2 in 1974 ranged from 3
to 75, the averagę being 50, in 1975 the eorresponding figures were
24-112 and 55.
The number of bumblebees in 1974 was 6 per 100 m2 and 19 in 1975.
Most frequently visited by bees and bumblebees were the varieties with
the biggest quantity of flowers per 1 m2 and the highest seed erop: the
most productive "Pelly Sweden" was visited by the biggest number of
H -
Pszczelnicze Zeszyty Naukowe
209
bees 112. Other insects (butterflies etc.) found on crop were
fewer in number: 30 insects per 100 m2•
The correlation between the amount of bees visiting
kind of clover and its crop was visible but low (r = 0,37).
stinct correlation was observed between the average nectar
and the seed yield: r = 0,48.
considerably
a particular
A more diaccessibility
The effect of Alar on clover. During 10 consecutive days 50 flowers
from 5 varieties of tetraploid clover was treated with Alar 85. In all
500 such flowers were compared with 500 flowers of the same control
species. The heads of clover treated with Alar differed in appearance:
they were more dense and had shorter flower tubes,
The results of the experiment (Table 4) show that Alar brought
about a shortening of the tubes in these clovers by 15%, from 9,3 mm
to 7,9 mm. The height of the nectar increased by 0,16 mm, that is by
14%. As a result the distance to the nectar in the flowers treated with
Alar decreased by 18%, from 8,1 to 6,6 mm. Eventually, the nectar
accessibility in these flowers increased four fold, from 14 to 59% in
comparison with the control species.
Moreover, Alar affected the quantity of flowers per 1 m2: the aveTable
4
Comparison of different varieties of red clover after treatment with Alar-85
II crop 1975 (average of 5 varieties; 100 flowers examinned from each variety)
feature
examined
tube lengths (mm)
Distance to nectar (mm)
nectar height (mm)
nec tar accessibility
for bees (in %)
control
variety
treated
with Alar
Difference
in mm
Difference
in %
9,3
8,1
1,18
7,9
6,64
1,34
-1,4
-1,46
+0,16
-15
-18
+ 14
14
59
+421
s
Table
Comparison of number of flowers after treatment
II crop 1975 per 1 m2
Variety
control
variety
with Alar 85
Variety
treated
with Alar
Grodkowice
Pelly - Szwecja
MT 1 NRD
Jubilatka
388
335
550
374
651
490
766
479
Averagę
412
100
596
145
%
210
increase
68
46
39
28
(%>
Table
6
Comparison of r~d clover seed yield treated with Alar 85
with control variety in relation to l ha.
Variety
control
variety
Difference
Variety
treated with
Alar
kg
%
Grodkowice
Pelly Szwedzka
MT l NRD
Jubilatka
82
144
280
103
400
209
345
348
+318
+65
+65
+ 184
388
45
23
179
Averagę
152
326
158
114
rage for the 4 control varieties of clover treated with it showed 596
flowers, that is the increase in their numbers reached 45% (Table 5).
As a result of the increase in the number of flower s and the heightened nectar accessibility a remarkable rise in clover seed yield was
obtained. The average crop of the 4 control species per 1 hectare amounted to 152 kg and the yield of those treated with Alar reached 326 kg/ha.
The figures for other varieties ran from 23 to 388 kg.
SUMMARY
l) Several varieties of tetraploid clover with the highest seed crop were discussed.
2) The differences in flower tube lengths and nectar height found in particular
varieties was defined, different nectar accessibility for bees recorded.
3) It was observed that first seed crop was 3 tirnes bigger than the second
crop.
4) The marked influence of Alar 85 on the increase in quantity of flowers (by
45%) and a shortening of flower tubes was obseved. As a result of administerlng
Alar the following was obtained:
a) A twofold increase in the tetraploid red clover seed crop,
b) A fourfold increase in nectar accessibiJity for hybrid bees which should ensure
a higher honey crop,
LITERATURE
D e m i a n o w i ~ z Z. (1957) - O oblatywaniu przez pszczoły 2 odmian koniczyny
czerwonej. Pszczelno Zesz. Nauk. nr 2.
Gór a I St. (1965) - Wpływ niektórych czynników na zapylanie i osadzanie nasion u di- i tetraploidalnej
koniczyny czerwonej. Post, Nauk Roln.
H u l e w i c z o w a - L ą c z y ń s k a T., J. H o r t y ń s k i (1970) Wpływ niektórych regulatorów wzrostu na plon nasion i jego strukturę u poliploidalnej koniczyny czerwonej. Cz. I. Wpływ CCC na rozwój i plon nasion. Cz. II. wpływ
14"
211
TIBA, 2-4-5
TP, IAA i DMSO na rozwój i plon nasion. Biuletyn
nr 3-4.
•
J a b I o s k i B. (1962) Próba oceny nektarowania
koniczyny czerwonej przy
selekcji nowych odmian. Pszczelno Zesz. Nauk. rok 6, nr 2.
J u I e n G. (1954) - Eur, Grasal, Conjer, Paris OEEC, 69-72.
J u I e n G. (1956) - Prac. 7th Intern. Grassl, Congr. 471-478.
K a z u b o w s k a - M a c k i e w i c z T. (1964) - Badania cytologiczno-ernbriologlczne
przyczyn słabego wiązania nasion u koniczyny czerwonej tetraploidalnej
(Trifolium
pratense L.) w porównaniu
z formą diploidalną. Poznań, Praca doktorInstytutu
T, 2-4-5
Rod. i Aklimat.
Roślin
ń
ska.
P i c a r d P., S i g v a I t C. (1967) - Acad. d'Agrtculture
de France, 25 Janvie,·,
s. 141-148.
S kir d e W. (1966) - Zeit tur Acker.u. Flanzenbau, t. 119, s. 263-282.
V a II e O., K I a u s B. (1966) - Acta Aqral, Fennica, t. 104, s. 1-20.
W a w r y n T. (1973)
Wykorzystanie
pszczół w podnoszeniu plonu nasion koniczyny czerwonej - (Trifolium
pratense L.) Rocz. Nauk. Roln. S.A.T. 98, Z. 2.
POROWNANIE ROŻNYCH ODMIAN KONICZYNY CZERWONEJ
TETRAPLOIDALNEJ
ORAZ BADANIE WPŁYWU INHIBITORA ALAR-85
NA SKUTECZNOŚC ZAPYLANIA KONICZYNY PRZEZ PSZCŻOŁY
Ta ded usz Waw
l'
y n, Pszczela Wola, Polska
Streszczenie
Wyłoniono kilka odmian koniczyny tetraploidalnej
o najwyższych plonach nasion. Stwierdzono różnice w długości rurek kwiatowych i wysokości słupka nektaru
u poszczególnych odmian, a w związku z tym różną dostępność odmian koniczyny
dla pszczół .Uzyskano 3-krotnie większy plon w I pokosie niż w II, stwierdzono
wybitnie dodatni wpływ Alaru 85 na zwiększenie liczby kwiatostanów
(o 450'1)
oraz skrócenie rurek kwiatowych, co dało w efekcie:
a) dwukrotne zwiększenie plonu nasion czerwonej 'koniczyny tetraploidalnej
b) 4-krotnie większą dostępność nektaru koniczyny dla pszczół krzyżówek, co pozwoli na większy zbiór miodu.