Sheshshayee, M. S.CHAITANYA, M. P.2023-01-162023-01-162022-12-27Th-13462https://krishikosh.egranth.ac.in/handle/1/5810192384Rice is traditionally cultivated in the semi-aquatic flooded condition, consuming 50% of freshwater. The diminishing water resources and prevalent climate change challenges demand to development of lesse water consuming cropping systems. Though closely related cereal, wheat requires substantially less water than rice without compromising on yield. A comparative study was carried out to investigate the underlying drought tolerance mechanisms between rice cultivars IR64 (lowland), Apo (aerobic) and wheat variety Weebill. Using the high throughput drought simulation phenotyping facility, precise moisture stress was imposed at the vegetative stage. Variability in the stress response was captured by performing untargeted metabolome analysis. Distinct accumulation patterns of the metabolites were observed under control and stress treatments, both within and between the species. Under the water deficit condition, polyamine, sphingosine-1-phosphate, anthranilate, flavonoid and flavone biosynthetic pathways were significantly upregulated. To validate the identified metabolites, 14 contrasting rice genotypes were selected which were previously reported to have acquired tolerance traits (ATT’s). The biochemical and physiological assays proved the consistency of ATT’s similar to previous studies. Further validation for key regulatory genes in the metabolic pathways was conducted through gene expression analysis. With final goal of enhancing drought tolerance mechanisms in rice, some promising rice genotypes genotypes which had fold change levels comparable to that of Weebill were screened, which can be utilized in future crop improvement studies.EnglishThesis