Physiological characterization of bread wheat genotypes for heat tolerance
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Date
2021-07
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CCSHAU, Hisar
Abstract
The present study entitled “Physiological characterization of bread wheat genotypes for heat stress tolerance” was conducted on 15 wheat genotypes. The experiment was laid out in Randomized Block Design with three replications, under two sowing dates viz., 17th November and 24th December, at the research area of Wheat and Barley Section of Department of Genetics & Plant Breeding, CCS Haryana Agricultural University, Hisar during rabi 2020-21. Observations were recorded for seven physiological traits viz., Normalized difference vegetation index (NDVI), canopy temperature, above ground biomass, chlorophyll content index (SPAD), photosynthetic rate, transpiration rate and stomatal conductance; and 9 morphological and yield attributing characters viz., number of days to heading, number of days to anthesis, number of days to maturity, plant height (cm), number of spikelets per spike, spike length (cm), number productive of tillers per m2, number of grains per spike, grain weight per spike (g), 1000 grain weight (g), biomass (g/m2), grain yield (g/m2) and HSI. In all the wheat genotypes, i.e. G1 to G15 observations were taken at different stages of growth for physiological studies, while yield characteristics were recorded at maturity. Genotypes G12, G13, G14 and G1 performed better under TS condition while genotypes G13 and G14 under LS condition in terms of having higher NDVI, Chlorophyll Content Index, photosynthetic rate, transpiration rate, stomatal conductance, biomass, yield and its attributes. Highly significant correlation between grain yield and physiological traits was observed viz., photosynthetic rate, NDVI, Chlorophyll Content Index, stomatal conductance and transpiration rate under TS and LS conditions, therefore, these traits can be considered as key component traits for enhancement of grain yield in wheat under heat stress conditions. Heat susceptibility index (HSI) was used to assess heat tolerance in the experimental material. The genotype G14, followed by G13 and G4 were found to be most tolerant to heat stress based on lower HIS respectively (0.74), (0.75) and (0.87) whereas G6 was recorded to be most susceptible based on highest HSI to heat stress under LS condition.