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Subject: Plant Breeding × End date: 2002 × Start date: 2002 × Type: Thesis ×
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    ThesisItemOpen Access
    Heterosis and gene action in bajra - napier hybrids
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2002) Serene Das, M; KAU; Suma Bai, I
    A study on 'Heterosis and gene action in bajra-napier hybrids' was carried out with the objective of developing bajra-napier hybrids with high yield potential and good quality. The study was undertaken during the year 2001-2002 in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani. Seven lines of bajra, viz., APFB-2, Composite 9, DRSB-3, FD 1917, HES-4, IP 15814 and TNSC-4 and three testers of napier grass, FD 431, FD 467 and FD 471 were crossed in a line x tester mating design to obtain 21 cross combinations. The hybrids were evaluated along with their parents for mean performance, combining ability, heterosis and gene action for eleven yield and yield related characters. Significant differences among treatments were observed for all the characters. Also significant differences among parents and crosses were observed for these characters and their general and specific combining ability variances and effects were studied. The magnitude of SCA variances alone was significant suggesting the predominance of non-additive gene action in controlling these traits. Based on mean performance and gea effects, HES-4 was identified as the best general combiner among lines followed by TNSC-4. Among testers, FD 467 can be selected as the best male parent followed by FD 471. The crosses, TNSC-4 x FD 471 and HES-4 x FD 467 were the promising combinations for green fodder yield and its component traits, based on mean performance, sea effects and standard heterosis. Hence these crosses can be exploited for developing high yielding hybrids.
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    ThesisItemOpen Access
    Quantitative variation and genetic divergence in fodder rice bean [Vigna umbellata (Thunb.) Ohwi and Ohashi]
    (Department of Plant Breeding and Genetics, College of Agriculture,Vellayani, 2002) Salu Appan, B; Suma Bai, D I
    I\. research programme was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 1999-2000 with the objective of estimating the variability in the important economic characters and the genetic divergence among the accessions in order to group them into clusters based on the magnitude of genetic distance using Mahalanobis 02 statistic. The experiment was conducted using 60 accessions adopting a randomised block design with two replications. Data collected on eleven characters were subjected to statistical analysis. Coefficient of variation, heritability, genetic advance, correlation among the characters, path coefficient and genetic divergence were estimated. Analysis of variance revealed significant differences among the accessions for all the characters except duration of the crop. Phenotypic and genotypic coefficient of variation were high for leaf weight per plant, number of leaves per plant and green fodder yield. I ligh heritability coupled with high genetic advance was observed for plant height, leaf weight per plant, green fodder yield and dry fodder yield. Correlation studies indicated that plant height, number of leaves per plant, leaf area index, leaf weight per plant, dry fodder yield and crude fibre content exhibited significant positive correlation with green fodder yield. vii Leaf weight per plant exhibited the highest positive direct effect on green fodder yield followed by plant height. Number of branches per plant and leaf area index recorded negative direct effect on green fodder yield. Based on the genetic distances computed with respect to ten characters studied, the 60 accessions of fodder rice bean were grouped into five clusters while accessions LRB 235, LRB 221, LRB 225, RBL 118 and LRB 145 remained as single. Maximum divergence was obtained between C4 and CID while divergence was minimum between Cl and C3. Hence, selection of parents from C4 and CIO will be effective [or an overall improvement of fodder yield. viii