Sharma, PushpPriya2020-11-022020-11-022020Priya (2020). Characterization of morpho-physiological and biochemical trait for heat tolerance in Indian mustard (Brassica juncea L. Czern. & Coss) (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.https://krishikosh.egranth.ac.in/handle/1/5810154082The present investigation “Characterization of morpho-physiological and biochemical trait for heat tolerance in Indian mustard (Brassica juncea L. Czern. & Coss)” was conducted in timely and late planted set of forty nine advanced breeding genotypes in two rabi seasons (2016-17 and 2017-18) at Punjab Agricultural University, Ludhiana and Dr. JC Bakhshi, Regional Research Station, Abohar which were further evaluated in the temperature gradient tunnels (TGT), Department of Climate Change and Agricultural Meteorology, Punjab Agricultural University, Ludhiana with the objective to standardize the screening techniques for heat tolerance based on morpho-physiological, biochemical and yield traits. Experiments were laid in factorial randomized block design. High temperature experienced by late planting led to reduced phenological duration at both locations while genotypes attained late maturity in TGT (13 days). Physiological traits like chlorophyll content, SPAD value, LAI and PAR (%) increased from vegetative to flowering stage followed by decline at siliquing stage whereas chlorophyll and SPAD value increased in TGT at flowering and siliquing stage. Lower CTD, decline in RWC (23.0%), LWR (12.0%) and MS (36.3%) while increase in WSD (16.8%), RSD (15.4%) and MI (18.1%) under delayed sowing. The high demand for utilizing stem reserve but lower accumulation and translocation of photoassimlates led to the imbalance between source to sink translocation in delayed planting however up regulation of antioxidative enzymes and non enzymatic antioxidative biomolecules imparted thermo tolerance. Positive association of seed yield existed at two locations with phenological durations, BY, HTI and HSI. Selection criteria of seed yield reduction (<30%), lower HSI (≤1) and higher HTI (≥1), over the years at two locations rated PCR-3, CSR-158, HLM-4113-2, ELM-38, CSR-1163, JMG-244 and CM-21-16promising. Three genotypes PCR-3, ELM-38, CSR-1163 were identified heat tolerant at two locations and in temperature gradient tunnels.EnglishThesis