Screening of bread wheat genotypes for heat tolerance using artificial and natural environment

Increasing temperature because of climate change is one of the leading constraints to wheat productivity by adversely affecting its growth and development. Global warming would push the wheat cultivation further into heat stressed environment in future which may ultimately cause yield loss. This research directed for determination of heat tolerance level among different wheat genotypes to establish selection criteria under high temperature to select promising wheat genotypes for breeding. Hundred wheat accessions including 97 lines from international Maize and wheat improvement centre’s (CIMMYT) heat nurseries and three local checks were assessed for tolerance against high temperature in glass house and open field. In glass house, at seedling stage data was recorded for fresh shoot weight, dry shoot weight, leaf relative water content and electrolyte leakage. In open field data for heat and yield related traits were recorded and subjected to mean square analysis. Studied traits were pooled through cluster analysis. Results showed that these traits have potential to discriminate heat tolerant and susceptible genotypes. Variances between genotypes were highly significant for all investigated traits under both circumstances. Accessions HTSBWON-15-0002, HTSBWON-15-0029, HTSBWON-15-0040, HTSBWON-15-0079, HTSBWON-15-0087, HTSBWON-15-0089 and Faisalabad-08 performed good for heat and yield related traits particularly electrolyte leakage and leaf relative water content. Hence, based on analysis it could be deduced that these genotypes may be used in hybridization programs for development of heat tolerant wheat genotypes with high yield potential.