Rice-wheat cropping is the major cropping system on 13.5 mha in the Indo-Gangetic plains (IGP) (Pathak et al., 2003; Panigrahy et al., 2011) producing about 50% of the total food grain and feeding 40% of India population (Gupta et al., 2016). Now, this rice-wheat cropping system has started showing declining trends in marginal yield due to 'heat stress' problem in last decade. Early onset of significantly higher temperature coincided with wheat grain filling stage especially in Indo-Gangetic

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... ins leading to terminal heat stress and reduction in yield. The present investigation has been carried out with 50 advanced genotypes of wheat targeted for heat stressed areas to assess the genetic diversity of wheat genotypes for yield and yield components along with physiological attributes and also to screen the genotypes against prevailing diseases of this area. Among the morpho-phenetic traits, only days to heading, plant height, awn length, spike length, spikelet per spike, 1000 grain weight and biological yield showed significant variation between genotypes. AUCIPC value calculated on the basis of Chlorophyll Index (CI), was highest in ENTRY 1 which indicated higher retention of chlorophyll at maturity. Canopy Temperature Depression (CTD) showed higher value for 13 genotypes at later stages which signified high physiological efficiency for these genotypes. Correlation study indicated cooler canopy temperature leads to higher grain yield and increased biomass. In terms of spot blotch resistance, no genotype was found either moderately resistant (MR) or resistant (R) category. D 2 analysis showed significant diversity between genotypes and it divided 50 genotypes into 5 clusters. In terms inter cluster distance value, most divergent cluster was found as cluster I and V. Five principal components (PCs) showed Eigen value >1.00, which accounted for 69.03% of cumulative proportion of variance. Biplot curve showed, in PC 1 characters such as BY, PH, GPS, AUCIPC had high positive loadings while AUDPC and CTD had negativ [...]