Browsing by Author "Sobha, P P"

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    Combining ability analysis in cowpea (Vigna unguiculata [L| walp)
    (Kerala Agricultural University, 1998) Sobha, P P; Abdul Vahab, M; Krishnan, S
    Combining ability was studied in a 10 x 10 diallel cross in cowpea for nine important characters. The variance due to general combining ability and specific combining ability showed both additive and non-additive gene action for plant height, primary branches, days to flowering, pod length, pod weight, pods per plant, seeds per pod, 100 seed weight and yield per plant. Among ten parental lines, Arka Garima, VU-18, Selection 2-1, Section 263, Pusa Komal and Kanakamoni were good general combiners for most of the yield components. The hybrids VU-18 x Arka Garima and Selection 2-1 x VS 389 possessed high specific combining ability effects for yield per plant.
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    Genetic variability, heritability and genetic advance in cowpea (Vigna unguiculata [L.] walp)
    (Kerala Agricultural University, 1998) Sobha, P P; Abdul Vahah, M
    Genetic variability studies in thirty one genotypes of vegetable cowpea revealed significant difference for all the characters except primary branches. A wide range of phenotypic coefficient of . variation (7.4 to 56.7) was observed. High genotypic coefficient of variation was observed for pod weight (54.6) and pod yield per plant (53.1). All the characters exhibited high heritability (78% to 97%). Heritability and genetic advance were high for pod weight and yield per plant, which can be relied up on for the effective genetic improvement of cowpea.
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    Variability and hetrosis in bush type vegetable cowpea (Vigna unguiculata(L) Walp.)
    (Department of Olericulture, College of Horticulture, Vellanikkara, 1994) Sobha, P P; Abdul Wahab, M
    etc. The present investigation on ‘variability and hetrosis in bush type vegetable cowpea (Vignaunguiculata (L.) walp.)’ was conducted at the College of Horticulture, Vellanikkara, Thrissur during 1992 - 94. Thirty one genotypes of cowpea collected from different parts of the country were grown in a randomised block design with three replications to assess the extent of genetic variability for fifteen characters viz. plant height, spread, primary branches, days to flowering, days to harvest, pod length, pod girth, pod weight, seeds/pod, flower bunches, pods/cluster, pods/kg, 100 seed weight, pods/plant, and yield/plant. The genotypic and phenotypic coefficients of variation, heritability, genetic advance and genetic gain were estimated. Based on D2 analysis and morphological observations, ten parents were selected and crossed in all possible combinations in a 10 x 10 diallel to produce 45 F1 hybrids. These F1 hybrids were evaluated along with their parents to derive information on general and specific combining ability effects and heterosis. Significant differences were observed among the 31 genotypes for all the fifteen characters studied. The highest genotypic coefficient of variation was observed for pods/kg, pod weight and yield. High heritability coupled with high genetic gain was observed for these traits. Days to harvest, pod length, pod girth, pod weight and yield. High heritability coupled with high genetic gain was observed for these traits. Days to harvest, pod length, pod girth, pod weight, pods/kg, seeds/pod and 100 seed weight were highly correlated with yield. Pod weight exerted the maximum direct effect on yield. Based on genetic divergence the 31 genotypes were grouped into six clusters. Polyacrylamide gel electrophoresis of cowpea seed proteins showed marked variation in banding pattern. Different cowpea varieties could be distinguished by the species specific bands. Significant gca and sca variances were observed for all the traits. Amb – 1, selection 263 and selection 2 - 1 were the best general combiners for earliness. Hybrids resulted from Amb – 1 x ArkaGarima and Vu – 18 x Amb – 1 recorded high sca effects for earliness. ArkaGarima and selection 2 – were the best general combiners for yield. The hybrids Vu 18 x ArkaGarima and Selection 2 – 1 x Vs 389 evinced high sca effects for yield. Significant heterosis were observed for all the traits in many hybrids. Several hybrids recorded significant negative relative heterosis, heterobeltiosis and standard heterosis for earliness. Amb – 1 x ArkaGarima and Vu – 18 x Amb – 1 were significantly early to flower compared to standard variety, ArkaGarima. Relative heterosis and heterobeltiosis were observed in many hybrids for yield/plant. Selection 2–1 x VS 389 and Vu – 18 x Amb – 1 showed high relative heterosis as well as heterobeltiosis. Vu – 18 x ArkaGarima and Selection 2 – 1 x VS 389 were the promising hybrids which exceeded the standard variety ArkaGarima for yield/plant.