Abstract

Wheat (Triticum aesum L.) production in Bangladesh is often impaired by heat stress. Therefore, it has been a priority to develop heat tolerant wheat variety for Bangladesh. An investigation was carried out to evaluate locally cultivated wheat genotypes for heat tolerance based on morpho-physiological and molecular markers. A pot experiment was carried out with ten locally cultivated wheat genotypes. Heat treatment was imposed, 5 days after anthesis, in a plant growth chamber at 35°C and 70% RH for 3 days. The heat stress affected all the yield contributing characters and ultimately led to a reduction in grain yield. BARI gom-29, BARI gom-30 and BARI gom-28 emerged as heat tolerant variety on the basis of susceptibility index and tolerance efficiency. While, Shatabdi, BARI gom-23, BARI gom-26 and BARI gom-24 were heat susceptible. Twenty six wheat genotypes were screened for heat tolerance through seven linked SSR markers that generated 44 alleles among the 26 wheat genotypes with an average of 6.28 alleles per locus. Overall polymorphism information content (PIC) and Nei’s gene diversity were 0.68 and 0.72, respectively. Similarity indices based unweighted pair group method with arithmetic mean (UPGMA) analysis separated 26 genotypes into five different clusters. Two morphologically identified tolerant genotypes namely BARI gom-29, BARI gom-30 and one moderate genotype BARI gom-22 were grouped in cluster 2. Therefore, these three varieties can be suitable for cultivation in the north-western part of Bangladesh as heat tolerant cultivars.

Key words: Diversity, heat tolerance efficiency, heat susceptibility index, SSR marker.