Department of Botany, Punjab Agricultural University, Ludhiana-141001, India.
A field experiment was conducted during rabi (winter) season. Five wheat cultivars (PBW-343, WH-542, PBW-502, PBW-509 and Raj-3765) sown on six dates of sowing starting from 31st October at weekly interval upto 5th December to find out suitable thermotolerance traits and genotypes. Amongst eleven traits recorded at different growth stages, largest variability was observed in crop growth rate (CGR), partitioning to spike, grain spike weight ratio (GSWR), spike growth duration (SGD), cumulative growing degree days (GDD) accumulated during vegetative and reproductive phenophases and grain yield at maturity. The highest grain yield was correlated with longer spike growth duration, partitioning higher crop growth rate and grain spike weight ratio at anthesis phase. The results revealed that cumulative growing degree-days (GDD) accumulated more during the reproductive phases as compared with the vegetative phases of wheat cultivars. The GDD is the effective selection criteria for screening thermotolerant lines of wheat.
Heat, Spike-growth duration, Grian-spike, weight ratio, Wheat
