Impact of Post-Anthesis Heat Stress on Physiological and Biochemical Traits of Wheat Genotypes

This study was conducted to identify physiological and biochemical attributes of wheat genotypes in response to heat stress. In this respect eight wheat genotypes viz., Pavon-76, Prodip, BARI Gom-25, BARI Gom-26, BAW-1143, BAW-1146, BAW-1147 and BAW-118 were used as study materials. The experiment was conducted during 2011-12 and 2012-13. In this experiment, physiological changes of wheat genotypes were evaluated in relation to heat tolerance in field condition by seeding them at November 27 (normal), December 17 (late) and January 7 (very late growing condition) over two successive years. HT genotypes showed higher canopy temperature depression (CTD) in each growing conditions than the MHT and HS genotypes. At late and very late growing heat stress conditions, HS genotypes exhibited larger increase in flag leaf proline at 8 days after anthesis (DAA) than the MHT and HT genotypes. At normal growing condition, the variation of total chlorophyll content in flag leaf among the HT, MHT and HS genotypes were lower compared to late and very late growing condition. The chlorophyll reduction at late growing heat stress condition was clearly distinguishable between the HT and HS genotypes.