Genetics of major biochemical components in groundnut (Arachis hypogaea L.)

Abstract

Nine groundnut genotypes were crossed in half diallel fashion to study the combining ability and gene action in respect of oil, protein and total soluble sugar content. The magnitudes of general combining ability (GCA) variances were higher than specific combining ability (SCA) variances in F1 and F2 generations indicating that additive effects were more pronounced than non-additive effects. The parent TPG 41 was a good general combiner for high oil content, but poor combiner for protein and sugar content. The genotype NRCG 10389 was a good general combiner for protein content, while parent NRCG 201 was a good general combiner for protein and total soluble sugar content. A number of cross combinations involving theses genotypes indicated high positive effects for oil, protein and total soluble sugars, but none of the crosses showed consistently significant sca effects over generations. The ratios of average degree of dominance were also in the range of over dominance for all the traits. Dominant and recessive alleles were not equally distributed among the parents with respect to all the traits. The ratio of dominance to recessive alleles for oil and protein content showed that the dominant genes were less than the recessive ones, while for the total soluble sugar, dominant genes were in excess. Moderate narrow-sense heritability was recorded in both F1 and in F2 generations for all three traits.