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18
PNL Volume 20
1988 RESEARCH
REPORTS |
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YIELD COMPONENTS AND THEIR
INFLUENCE ON YIELD IN A BASIC COLLECTION FOR DRIED PEA
BREEDING
Jaiser, H. Inst, fur Angewandte Genetik, Freie Universitat,
Berlin, FRG
During the last three years about
2000 lines from several gene banks have been evaluated for about 55
morphological and yield characters. The aim of the project was to select
useful parents for crosses in a breeding program of dried peas. About 100
lines have been chosen for standing ability, disease resistance, and
varying components of yield after two consecutive steps of selection.
Among these lines were about 22 semi-leafless genotypes with different
genetical backgrounds, 8 "rabbit-eared" rogue types (1), and some
primitive lines.
The selected lines were planted in
1987 at four sites in observation plots of 7.5m2 size. At one
location 20 plants per plot were pulled from the center of the plot to
score various yield characters. The following measurements were
taken: number of seeds per pod, number of pods per main stem, number of
flowering nodes, flowers per node, number of seeds and pods on branches,
seed weight, and single plant yield. Fertility was estimated by
dividing the number of seeds per pod by the number of ovules and pod set
was determined by dividing the
number of pods by the number of possible pods. The. influence of different plant types and of
variation in yield components on seed yield is reported.
Bad weather in summer 1987 caused
environmental stress. Thus abortion of seeds, flowers, and pods was
relatively high. Table 1 shows the mean values of the yield characters
studied for different plant
ideotypes. The reduction of pods is extreme in rogue types, corroborating
earlier observations that they
react to stress with pod dropping (2). Fertility in the pod was also
reduced. Semi-leafless lines
produced more pods than conventional types but had a slightly lower fertility.
Lines with more than two flowers per
node had a lower pod number than the normal two-flowered types. Whereas
82.2% of the possible pods were formed in lines with one flower per node
and 55.0% in the normal lines, the multi-podded genotypes realized
only 32.5% of the possible
pods. Higher within-plant competition also led to a reduction in seed
set.
There was no increase in the number
of pods in lines with a higher number of flowering nodes. Six to nine
flowering nodes seemed optimal to give the highest seed
yields.
Genotypes with a higher ovule number
were able to produce more seeds
under the unfavorable conditions of this growing season (Table 2). This confirms experiments
of Snoad and Arthur (3) with six vining pea varieties in different
environments. According to
their results abortion of
flowers and pods is greater than in ovules and seeds. The use of parents
with a higher ovule number and a medium seed weight (200-250) in crosses
should result in a more stable improvement of
yield. |
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1. Gent, G. P. and R. F. Knight.
1978. PNL 10:105-106.
2. Snoad, B. 1985. In: The Pea Crop.
P. D. Hebblethwaite,
M. C. Heath, and T.C.K. Dawkins,
eds., Butterworths, London, p. 31-41
3. Snoad, B. and A. E. Arthur. 1974.
Theor. appl. Genet. 44:222-231. |
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P.NL Volume
20 |
1988
RESEARCH REPORTS |
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Table 1. Mean values of yield
characters for conventional, semi-leafless, and rogue
types. |
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Table 2. Influence of increasing
ovule number on yield characters (excluding rogue
types). |
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