Assessment of genetic variance components in single cross hybrids of maize (Zea mays L.) using line x tester analysis

The study comprised of twenty four F1’s generated by crossing eight genetically diverse lines with three testers as per procedure suggested by Kempthrone (1957). The parents along with their F1’s were evaluated in a randomized complete block design with two replications at two locations for yield and yield contributing traits. Highly significant differences were found among lines and line × testers for all the traits both in individual as well as pooled analysis confirming that the material selected for crossing was diverse. The estimates of components of genetic variance revealed that dominance component played a predominant role for traits viz., plant height, kernel rows cob-1, grain depth, 100-grain weight, shelling percentage, grain yield plant-1 and protein content whereas additive component played a great role in rest of the traits in individual as well as in pooled analysis. The degree of dominance was greater than unity (over dominance range) for most of the traits that included plant height, kernel rows cob-1, grain depth, 100-grain depth, shelling percentage, grain yield plant-1 and protein content indicating that the present study of materials was diverse and contained contrasting alleles in most of the cases in dispersion phase, which on combination through hybridization increased heterozygosity. So, in the present set of experimental material greater contribution of non-additive gene action suggested exploitation of the gene action through heterosis breeding.