Photothermal indices in relation to phenology of wheat

A field experiment was conducted at the Experimental Farm of Haryana Agricultural University, Hisar during rabi season 1998–99 to study the phenology and photothermal indices of wheat crop under different sowing dates. The daily heat units were calculated using 5°C as base temperature for wheat. The occurrence of different phenological stages i.e. tillering jointing, flag leaf, anthesis, milking, hard dough and maturity required higher heat and photothermal unit at all stasges in 0 1, (25th November) sown crop followed by D₂ (10 December) and D₃ (25 December). Among the varieties V₂ (PBW 343) consumed maximum heat and photothermal units for occurence of different phenological stages followed by UP 2338, WH 542, Raj 3765 and Sonak, respectively.