GENETIC ANALYSIS FOR TERMINAL HEAT STRESS IN BREAD WHEAT (TRITICUM AESTIVUM L. EM THELL)

Abstract

High temperature during reproductive and grain filling phages causes significant yield losses to wheat in South
Asia and many other parts of the world. In present investigation out of 54 wheat cultivars/lines screen for terminal
heat stress ten cultivars/lines classified as highly tolerant, tolerant, moderately tolerant, and susceptible to heat
stress were mated in diallel fasion to generate 45 F1 hybrids which were evaluated using RBD in both normal and
heat stress conditions at BHU, Varanasi, India. Genetic parameters for morpho-physiological traits viz. days to
50% heading, plant height, 1000 grain weight, grain yield plant-1, canopy temperature depression (CTD), cell
membrane thermostability (CMS) and heat susceptibility index (HSI) were estimated. Parents HUW-234 followed by PBW-175, HD-2888 and DBW-14 in both normal and stress environment having good GCA along
with high per se performance for canopy temperature depression and cell membrane themotability could be used
as donor for terminal heat tolerance in breeding programme. For CTD and CMS h2
(ns) estimate were high. Since
the identified genotypes can cope up the effect of heat stress, they can be utilized for developing heat tolerant
genotypes.