Genetic Studies in Some Cowpea (Vigna Unguiculata (L) Walp.) Varieties in Ghana
Date
1987-09
Authors
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Publisher
University of Ghana
Abstract
Variation in some growth and y ie ld characteristics were studied in
16 lo ca l and exotic cowpea varieties grown in the country. ELanting
was done at three different times of the year representing three
seasons. The characters studied were: days to 8C$S germination, days
to 5<$> flowering, average dxy weight per plant at 5<?S flowering,
number of nodules per plant at 5C$> flowering, percent e ffe c tiv e
nodulation, number of branches per plant, number of peduncles per
branch, number of pods per peduncle, pod length, number of seeds per
pod, 10O-seed weight, days to 5Q& pod maturity, grain y ie ld per plant,
grain y ie ld per p lot, resistance towards cowpea mosaic virus (GMV) and
shattering in the f ie ld . Separate experiments were also conducted to
te s t v a r ia b ility in harvest index,resistance to bruchids in storage
and ease o f cooking the dzy seeds without using tenderizers.
Analysis of variance indicated that the varie tie s differed
significantly from one another in respect of a l l the characters studied.
Variety-season interactions also varied significantly fo r most characters
studied.
Among the yield-influencing factors, only 100-seed weight and
harvest index showed significant correlations with grain y ie ld .
percent crossability was variable among s ix varieties used as
parents in h e r itab ility studies of some quantitative t r a its . There
was also selective genotypic cross compatibilities among the varieties used.
Narrow sense h e r ita b ilitie s determined fo r 100-seed weight, seeds
per pod, pod length, branches per plant, peduncles per branch and pods
per peduncle were 80.C^, 74.C$>, 70.C$3, 68.0^2, 3 0 . and 22.
respectively.
Heterosis in the F s fo r yield-influencing characters was
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determined at both mid- and better-parent le v e ls . A ll crosses showed
heterotic response exceeding \0<2,Z fo r pods per peduncle and grain
y ie ld per plant at both le v e ls .
Hundred-seed weight and harvest index were found to be of higher
sele ctive value than other yield-influencing factors in cowpea
improvement.
None of the varieties tested f i t t e d the description of an ideal
cultivar suitable fo r recommendation to farmers in the country. In
order to get a proven variety, i t was suggested that hybridization
be used to combine a l l desirable characters into a single compound
or multiple cross variety.
Description
Thesis (MPhil)-University of Ghana, 1987