Differential reaction of wheat genotypes to phenologieal development, heat unit consumed, thermal use efficiency and grain yield

摘要

A field experiment comprising 25 aestivum wheat genotypes was conducted during rabi season of 2002-03 to study the reaction of wheat genotypes to their phenologieal development with respect to anthesis and maturity, heat unit consumed, thermal use efficiency and grain yield. The experiment was conducted under normal (17 November) and late (17 December) sown under irrigated conditions so as to expose the genotypes to heat stress. The results revealed that the late sowing reduced the period required for anthesis and physiological maturity. The heat unit consumed (thermal requirements) of all genotypes varied according to their phenophases and time of sowing. The genotype 7C/FRANGO-60 consumed minimum heat units and the genotypes TEPOLA/RABE and PBW-373 required maximum heat units to complete their life cycle. The thermal use efficiency for grain yield and biomass yield was found to be less with delayed time of sowing. The thermal use efficiency for grain yield and biomass yield was highest in 7C/FRA~NGO-60 under both the sowing dates and it was lowest in WH-712 and PBW-73 under normal and late sown conditions, respectively. Consistently higher grain yield was recorded in NL-623-ONPL and 7C/FRANGO-60 under both sowing dates by showing their toleranceto heat stress.