Effect of canopy temperature and stress degree day index on dry matter accumulation and grain yield of wheat (Triticum aestivum L.) sown at different dates in the Indo-Gangetic plains of Eastern India

Temperature change with concomitant change in canopy temperature influences crop growth and productivity. A three year (2005–06 to 2007–08) experiment was carried on wheat varieties PBW 343, HD 2733, HW 2045, PB 533 and K9107 in subplot treatments sown on three dates of 18^th November, 3^rd and 18^th December in main-plot treatments in a split-plot design with three replications. Canopy temperature was measured at CRI, tillering, flowering and milking and stress degree day index was computed. Late sown crop experienced highest canopy temperature, varieties of K 9107 and HW 2045 recorded lowest and highest respectively. Canopy temperature and stress degree day index significantly and negatively correlated to dry matter accumulation in leaf, stem and ear at different phenophases. Grain yield reduce significantly with the delay in sowing. Canopy temperature at 11.30h during CRI, tillering or flowering stages significantly and negatively affected grain yield.