STRESS RESPONSE BEHAVIOR IN WHEAT SPECIES IN RELATION TO HEAT TOLERANCE

Abstract

Eighty wheat genotypes , twenty each from  Triticum aestivum, Triticum durum, Triticum dicoccum and Synthetic T. aestivum  were evaluated for terminal heat tolerance by normal (non-stress) and late (stress) planting in field in randomized block design with three replications for two crop seasons; 2012-13 and 2013-14. The genotypes differed significantly for grain yield in non-stress and stress conditions. The heat susceptibility and tolerance indices were calculated as Heat Sensitivity Index (HSI) and Heat Response Index (HRI) for grain yield. Genotypes PBW 550, HD 2733, HD 2967, PBW 343 & PBW 373 from T. aestivum, WHD 943, WHD 945, WHD 314, WHD 946 & WHD 912 from T. durum, DI 26, DI 119, DI 88, DI 52 & DI 61   from T. dicoccum and Syn 22, Syn 24, Syn 30, Syn 36, Syn 62 & Syn 25 from T. durum was found heat tolerant on the basis of heat susceptibility Index and could be useful as genetic stock to develop wheat tolerant varieties in breeding programs. T. durum was found to have lowest HRI followed by T. dicoccum, Synthetic wheat lines and T. aestivum respectively while HSI was lowest in T. durum, T. aestivum, Synthetic wheat lines and T. dicoccum respectively.