Morpho-Physiologi cal and biochemical characteristics of wheat (Triticum aestivum l.) Varieties under heat stress condition

Heat stress due to the global warming is one of the major constraints in the way of higher wheat productivity. This field study was conducted to evaluate the effect of heat stress on the wheat yield, chlorophyll content, total soluble sugar and proline accumulation in leaves of wheat. A field experiment was conducted in the Department of Biotechnology, Keral Verma Subharti College of Science, Swami Vivekanand Subharti University, Meerut. During rabi season of 2017–18 with 8 genotype K-65, K-816, K-8434, K-9351, PBW 154, PBW 343, PBW 550 and PBW 226 sown on optimum date (November 25) and late (December 15) condition in a CRD with three replications to evaluate the performance of these genotypes under optimum and late sown condition and to find out the suitable time of sowing for a specific genotype. Under optimum sown condition, differences among the genotypes were found to be significant in respect of grain yield, plant height, grain filling duration, test weight, chlorophyll content of the flag leaf. While for the late sown condition, grain yield, plant height, grain filling duration, test weight, total soluble sugar, proline content and chlorophyll content of the flag leaf were affected due to variation among the treatment. For almost all the traits, reduction was caused due to late sowing with the maximum effect noticed for grain yield and chlorophyll content. From the present investigation, we can conclude that the PBW-550 is highly tolerant variety from the above given varieties for late sowing with reasonably high yield, moderate grain size and growth period. Under late sown condition, grain yield was positively and significantly correlated with chlorophyll content.