Effects of sowing dates on phenology, radiation interception and yield of wheat

An experiment was conducted during rabi seasons of 2015-16 and 2016-17 to study the phenology, accumulation of growing degree days (GDD), helio-thermal unit (HTU), photo-thermal unit (PTU), Heat use efficiency (HUE), Radiation use efficiency (RUE)and to assess the effects of thermal and radiation regimes on wheat at research farm of Department of Agricultural Meteorology, Chaudhary Charan Singh Haryana Agricultural University, Hisar during rabi seasons of 2015-16 and 2016-17.The twenty-seven treatment combinations were tested in split plot design with three replications. The main plot treatments consist of three date of sowing, i.e., D1-2nd fortnight of November, D2-1st fortnight of December, D3-2nd fortnight of December and sub plot treatments consist of three varieties, i.e., V1-WH 1105, V2-DPW 621-50 and V3-HD 2967.Daily meteorological data recorded at Agromet observatory near the experimental plot was used for computation of agrometerological indices, i.e., heat unit (HU), heliothermal unit (HTU), photothermal unit (PTU), heat use efficiency (HUE) and radiation use efficiency (RUE).The crop sown on 2nd fortnight of November took maximum no. of days, growing degree days, photo-thermal, helio-thermal unit. The accumulation of HU, HTU, PTU and HUE in early sown crop was higher due to more number of growing days taken for maturity as compared to late sown crops. HD 2967 consumed maximum HU, HTU, PTU and HUE due to longer growth duration as compared to other varieties. Grain yield showed a significant difference among the three different sowing dates during both the years and highest under 2nd fortnight of November sowing date. Mean grain yield of wheat crop in Rabi 2015-16, under different sowing dates, was more as compared to 2016-17 year. Different sowing dates significantly affected wheat productivity and biomass yield in both the years. WH 1105 variety resulted in higher yield as compared to other varieties, viz., DPW 621-50 and HD 2967.