Dr. Harpreet Kaur OberoiGurwinder Kaur2024-06-282024-06-282024Gurwinder Kaur (2024). Morpho-physiological, biochemical and molecular changes in BMR (brown mid-rib) sorghum under rainfed conditions (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.https://krishikosh.egranth.ac.in/handle/1/5810211097In the present investigation, two BMR (CSV 43 and SPV 2017) and non-BMR (CSV 15 and SPV 462) sorghum types were studied under irrigated and rainfed conditions at 45, 55, 65, and 75 DAS for morpho-physiological and biochemical parameters. Rainfed condition decreased green and dry fodder yields, along with morpho-physiological parameters in both sorghum types. Non-BMR genotypes exhibited higher yields under both irrigated and rainfed conditions. Higher SOD, POX, CAT and total antioxidant potential (FRAP, DPPH, TRP and HFRS) were observed under rainfed condition with lower H2O2 and MDA content in BMR genotypes over the non-BMR genotypes. Nitrogen assimilation enzymes (NR, NiR and GOGAT) decreased, while nitrate and nitrite N-content increased under rainfed condition in BMR and non-BMR sorghum. Rainfed condition increased the PAL, TAL activity and phenolic compounds in BMR genotypes compared to non-BMR genotypes. Moreover, due to better defence mechanism in BMR genotypes, fodder quality in terms of crude protein, crude fat, and IVDMD parameters was noticed to be higher as compared to non-BMR genotypes. Gene expression analysis revealed increased expression of stress-responsive genes (Gly-1, Gly-2, D-LDH, PAL, rubsico, SucS, stay green) in both genotypes under PEG 8000-induced drought stress. BMR genotype exhibited higher fold change in Gly-1, Gly-2 and SucS gene expressions, contributing to enhanced detoxification and photosynthetic stability. The present study suggests that BMR genotypes (CSV 43 and SPV 2017) compared to non-BMR sorghum genotype (CSV 15 and SPV 462) showed improved growth, enzymatic activities and gene expression related to defence to counteract the negative impact of rainfed conditionEnglishThesis