GENETIC STUDIES FOR SOME AGRONOMIC TRAITS IN SPRING WHEAT UNDER HEAT STRESS

F1 progenies of 7x7 diallel fashion crosses comprising four high temperatures tolerant and three susceptible spring wheat parental genotypes were evaluated under normal and heat stress conditions. the characters days to heading, spike index at anthesis, plant height, spikes per plant, spikelets per spike and grain yield per plant were studied under both conditions. analysis of variance under both conditions indicated additive gene action with partial dominance suggesting that these traits might be useful for the development of terminal heat tolerant varieties by modified pedigree selection.. however overdominance type of gene action was recorded for spikelets per spike suggesting that further improvement in this trait may be effected by biparental mating coupled with few cycles of recurrent selection.