Pantnagar Journal of Research

Abstract

A field study was conducted at the N.E. Borlaug Crop Research Center of G.B. Pant University of Agriculture and Technology, Pantnagar, to investigate the heat unit (GDD) requirements of wheat varieties under different dates of sowing and various irrigation levels in Tarai region of Uttarakhand. The experiment was laid out in Split Split Plot Design, with two dates of sowing viz. , D1 (1st December) and D2 (15th December), three irrigation levels I1 (IW/CPE ratio 1.0), I2 (IW/CPE ratio 0.8) and I3 (IW/CPE ratio 0.6) and two varieties V1 (UP 2855) and V2 (PBW 502). Studies showed that GDD needed to reach different phenological stages varies between the two sowing dates. Late-sown crops required more GDD for the booting (623.47) and milking stages (1065.08), while early-sown crops needed more GDD overall (1434.18). Irrigation levels affected GDD, with the lowest at emergence and the highest at maturity under irrigation level I1. Variety V1 (UP 2855) outperformed variety V2 (PBW 502) in GDD requirements across most stages.