Abstract

Twenty-eight hybrids of Zea mays L. produced in 2015-16 from 8×8 half diallel mating design were evaluated along with their parents in 2016-2017 under saline condition to find out genetic action and potency ratio of some agronomic and yield contributing traits. Genetic action and potency ratio were analyzed following Hayman’s diallel analyses and Smith’s formula, respectively. Genetic parameter like additive variance (D), dominance variance (H1), proportion of positive and negative genes in the parents (H2), relative frequency of dominant and recessive alleles in the parents (F), dominance effect over all loci in heterozygous phase (h2) suggested that traits like days to tasseling, days to silking, anthesis silking interval, ear height and number of grains/plant are governed by dominant alleles in these traits. Contrariwise, the data of plant height and 100-grain weight were shown to have higher frequency of recessive alleles. Proportion of genes with positive and negative [(4DH1)0.5 + F]/[(4DH1)0.5 – F] effects suggested the asymmetrical distribution of dominant and recessive alleles for all the traits except yield/plant. Under saline condition heritability in narrow sense (h2n) was found very low which indicates a possible strong influence of stress in the growing environment. These parameters along with Vr-Wr graphs and potency ratio indicated overdominance in desirable direction, and thus, heterosis breeding is important to improve those traits in maize under salinity.

Key words: Maize, salinity, genetic parameter, Vr-Wr, potence, inheritance.