Genetic analysis of yield and quality in fodder cowpea (Vigna unguiculata (L.) Walp)

Abstract

In the present study, "genetic analysis of yield and quality in fodder cowpea {Vigna unguiculata (L.) Walp)", evaluation of different fodder cowpea accessions were done to assess the variability in the available population to identify the good performers for forage yield and quality. Based on the morphological and molecular characterization superior parents were selected for crop improvement through hybridization to develop superior cross combinations. The salient features of the study are discussed below. Significant variation was observed for all tlie fourteen characters studied, the range of mean values observed refers to the phenotypic and genotypic variability present in the base population. High genotypic and phenotypic coefficient of variation was observed for number of primary branches plant ', number of leaves plant ', leaf area index, green fodder yield plant ', dry matter yield plant"', leaf fresh weight plant"', stem fresh weight plant"', leaf dry weight plant"', stem dry weight plant"' and crude fiber content. High heritability and genetic advance for crude fiber content, crude protein content, leaf area index, leaf dry weight plant ', dry matter yield plant"', stem dry weight plant"', number of leaves plant"', stem dry weight plant'', number of leaves plant"', stem fresh weight plant"', leaf fresh weight plant*' and green fodder yield plant"'. Green fodder yield and dry matter yield had significant positive phenotypic and genotypic correlation with leaf fresh weight plant"', followed by stem fresh weight plant"', stem dry weight plant"', dry matter yield plant"', leaf dry matter plant"', number of primary branches plant"' and number of leaves plant"'. The thirty fodder cowpea genotypes were grouped into eleven clusters. Maximum contribution to divergence was shown by leaf fresh weight plant"' followed by crude fibre content, stem dry weight plant"', leaf area index, dry matter yield plant*', number of leaves plant"', crude protein content and green fodder yield plant"'. Selection index was hi^est for IT-37154999-38 and least for IC- 202804. The genotypes were ranked for characters green fodder yield, crude protein content, crude fibre content and selection index. Based on this and maximum inter cluster distance eight genotypes CO-8, MFC-09-1, IC-1061, IC- 39916, IC-97767, lC-38956-1, 17-37154999-38 and Pant Lobia-2 were selected for further hybridization programmes. Molecular characterization revealed two clusters (I and II) with 0.34 per cent similarity. The statistical cluster diagram from value and dendrogram from molecular characterization were not similar. But the eight parents selected had considerable difference in dendrogram with minimum difference between parents IT-38956-1 and IT-37154999-38. Diallel analysis is one of the techniques used to find the genetic makeup. Gca variance was greater than sea variance, for all characters except for days to first flowering and crude protein content, indicating predominance of additive gene action for most of the characters. Days to first flowering and crude protein content had non-additive gene action. Presence of heterosis also shows the ability of the parents to combine well in a hybridization programme. Superior expression of Fi may be due to fixable (additive) type of gene action and non-additive type of gene action. Thus combining ability and heterosis helps in identifying desirable cross combinations. Twenty eight hybrids from eight parent were evaluated for combining ability in diallel mating design without reciprocals. Relative heterosis and heterobeltiosis were calculated for different traits. Gca variance was greater than sea variance, indicating predominance of additive gene action. P4, Ps and Pe were good general combiners among eight parents for plant height. Gca variance was greater than sea variance, indicating predominance of additive gene action in green fodder yield and dry matter jdeld. Ps, Pe, P? and Ps were good general combiners for green foddra* yield, dry matter yield, leaf fresh weight, stem fresh weight, crude protein content and crude fibre content. Nineteen of the hybrids were good specific combiners for I7f7^^ ni green fodder yield. Seventeen hybrids were good specific combiners for lower crude fibre content. Pi X ??, P2X P7, P5X P7 and P5X Pg were selected based on high green fodder yield, dry matter yield, higb protein content and low fibre content for raising F2 population. F2 families of these four hybrids exhibited differences among the progenies for different characters studied. Progenies of hybrid PiX P7 was identified as the best superior cross combinant useful for further improvement for superior variety development.