Heat susceptibility index and thermal requirement ofaestivum wheat genotypes under heat stress

摘要

A field experiment comprising 25 aestivum wheat genotypes was conducted during rabi season of 2002-03 to study the response of wheat genotypes to their heat susceptibility index for yield (S) and thermal requirement at anthesis and physiological maturity. The experiment was sown under normal (17 November) and late (17 December) sown irrigated conditions. The results revealed that the heat susceptibility index for yield (S) of different wheat genotypes ranged from 0.45 to 1.41. The genotypes viz., NL-623-ONPL (S=0,45) and 7C/FRANGO-60 (S=0.54) with low values of'S' were found to be heat tolerant as compared to rest of the genotypes. The thermal requirement of all genotypes varied according to their phenophases and time of sowing. The genotype 7C/FRANGO-60 consumed minimum heat units and the genotypes TEPOLA/RABE and PBW 373 required maximum heat units to complete their life cycle.