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Subject: Plant Breeding × Author: Rejatha, V × End date: 1999 × Start date: 1980 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Combining ability in vegetable cowpea
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1992) Rejatha, V; KAU; Ramachandra Nair, N
    A 6 x 6 diallel analysis was conducted at the Department of Plant Breeding, College of Agriculture, Vellayani, during 1990, aimed at analysing the combining ability, gene action and heterosis of six vegetable cowpea (Vigna unguiculata var-sesquipedalis) lines collected from the germplasm maintained in this department. The experiment I consisted of crossing the six parental lines in all possible combinations, without reciprocals. The material for experiment II consisted of the six parental lines and fifteen hybrids. They were grown in a Randomised Block Design with three replications.The combining ability analysis was carried out based on method 2 under model I as suggested by Griffing (1956). The treatments showed significant differences in most of characters except number of pods/plant and fruit yield/plant. The variance due to general combining ability was significant and higher in magnitude than specific combining ability for the characters days to flowering, mean weight of pod, mean length of pod, number of seeds/pod, length of internode and seed/pod ratio. It was found that the parent selection 104 and selection 145 were the best general combiners for most of the characters studied. The parent selection 129 was the best general combiner for earliness. The hybrids selection 145 x selection 129 was the best specific combiner for mean weight of pod and number of seeds/pod. The hybrid selection 145 x kurutholapayar was the best specific combiner for earliness. The significance of g.c.a. and s.c.a. variances for most of characters indicate the importance of additive and non-additive gene action in controlling the inheritance of these characters. But additive gene action played a major role suggesting that improvement could be made through selection. Heterosis was calculated over mid and better parental values. Maximum positive heterosis was found for the character fruit yield/plant. Since considerable heterosis was evident in most of the characters, heterosis breeding can be attempted in cowpea
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    ThesisItemOpen Access
    Combining ability in grass cowpea [Vigna unguiculata var- sesquipedails]
    (Department of Plant Breeding, College of Agriculture, Vellayani, 1992) Rejatha, V; KAU; Ramachandra Nair, N
    Two lines, six testers and twelve bybrids of cowpea were evaluated in the partially shaded conditions of coconut garden of Vellayani for combining ability and gene action. The lines and testers were selected based on their previous performance and crossed in line x tester manner to get twelve hybrids. Observations were made on sixteen characters of which twelve characters showed significant differences among the twenty treatments. Combining ability analysis was carried out as suggested by kempthorn (1957) suggested the importance of specific combining ability for all the characters except for length of pod and days to flowering. It was seen that the varieties chharodi – 1, Culture – 9, V – 26 and GC – 82 – 7 were the best general combiners and the cross combinations Chharodi – 1 x V – 26, Chharodi – 1 x Kanakamani and Culture – 9 x V – 322 were the best specific combinations for yield and yield attributes under partially shaded upland conditions. The yield and important yield attributes were under the control of non – additive gene actions except days to flowering and length of pod. The varieties Culture – 9, GC – 82 – 7,Chharodi – 1 and V – 26 and the cross combinations Chharodi–1 x V–26, Chharodi-1 x Kanakamani and Culture –9 x Kanakamani can be further exploited through selection