Evaluation of Bread Wheat (Triticum Aestivum L.) Genotypes for Heat Tolerance at Middle Hawash, Ethiopia

Abstract

The objective of the study was to evaluate bread wheat genotypes for their tolerance to heat stress. This research involved 49 wheat genotypes obtained from CIMMYT and Ethiopia's National Wheat Research Programme. The experiments were planted at middle Hawash in a partially balanced simple lattice design in two sowing dates under irrigation condition. The combined ANOVA for heat stress levels revealed highly significant differences (P=0.01) for heat stress levels (HL), genotypes (G) and G x HL interaction for all the traits studied. Most traits showed a reduced performance due to higher heat stress. There were highly significant correlations among all heat tolerance indices except heat tolerance efficiency with mean and geometric mean productivity, and percent yield reduction with mean grain yield. Under higher heat stress, grain yield was negatively correlated with canopy temperature (r=-39), days to flowering (r=-0.49) and days to maturity (r=-0.26). Yield was positively correlated with leaf area (r=0.48) and plant height (r=0.45). Most of the high yielding genotypes were tolerant to heat stress. Some of the low yielding genotypes were also tolerant to heat stress. The genetic variability observed among the genotypes could be exploited for future breeding aimed at the development of heat tolerant wheat varieties.