Abstract

A field experiment was conducted during rabi season of 2011 to 2012 at Maharana Pratap University of Agriculture and Technology, Udaipur to study the phenology, accumulated growing degree days, photo thermal unit, helio-thermal unit, heat use efficiency and performance of wheat varieties grown under different sowing dates. The crop was sown on 5^th November took maximum calendar days, growing degree days, photo thermal unit, helio-thermal unit to attend different phonological stages till maturity which reduced significantly with subsequent delay in sowing time. The grain yield recorded in 5^th November was statistically at par with 20^th November. The significant reduction in grain yield of timely sown varieties was recorded when sowing was delayed beyond 20^th November. Among the varieties highest grain yield of 62.81 q ha^-1 was recorded in varieties Raj 4037, which was significantly superior over HI-1544 (58.75 q ha^-1) and MP-1203 (50.32 q ha^-1). Among the varieties MP-1203 took highest calendar days growing degree days, photo thermal unit, helio-thermal unit to reach the maturity. The variety Raj 4037 recorded the highest grain yield at 5^th November sowing as compared to all other sowing dates.

Key words: Grain yield, growing degree day, photo-thermal units, temperature.