Mukesh KumarKavita2023-04-212023-04-212022-12https://krishikosh.egranth.ac.in/handle/1/5810196544In the present investigation 50 wheat genotypes were sown with two replications in a randomized complete block design (RBD) at the experimental area of Department of Genetics and Plant Breeding, CCSHAU, Hisar, during Rabi seasons of 2018-2019 and 2019-2020 under normal and late sown conditions. Combined ANOVA showed that all traits had high level of genotypic variations among all the genotypes under both conditions. Highest heritability was shown by days to anthesis under both conditions while high GCV, PCV and genetic advance as percent mean were high for relative stress injury and chlorophyll stability index under normal and late sown conditions, respectively. Biochemical parameters and heat stress indices were used to screen out heat tolerant genotypes. Grain yield per plot exhibited positive and highly significant correlation with membrane stability index, chlorophyll stability index and all yield contributing traits under both conditions. Correlation among heat stress indices exhibited that grain yield per plot under both conditions is positively correlated with stress tolerance index, yield index, mean productivity, geometric mean and harmonic mean. Path analysis showed that harvest index and biological yield per plot had highly positive direct effects on grain yield per plot under both conditions. The principal component analysis for morpho-physiological traits under normal and late sown conditions and heat stress indices depicted that the first four, three and two components reflected more than 78%, 76% and 97% of the total variance, respectively. Cluster analysis grouped genotypes into 7 and 5 clusters, most divergent clusters were IV and VI, II and V under normal and late sown conditions, respectively. UPGMA cluster tree analysis divided genotypes into two clusters and also confirmed that sufficient variability is present among genotypes. Transcriptome analysis revealed that the differentially expressed genes (DEGs) under control and heat stress conditions were identified in both genotypes (WH-730 and WH-1184). These DEGs were utilised to set up a subsequent unigene assembly and GO analysis was done using unigenes to analyze functions of DEGs which classified into three main domains; biological process, cellular component and molecular function. KEGG ontology was used to visualize the physiological processes or to identify KEGG pathways that provide plants their ability to shield in adverse conditions of heat stress. From KEGG ontology it was reported that the gene encoded enzyme (peroxidase) of KEGG pathway was upregulated in WH-730 while downregulated in WH-1184.EnglishThesis