Effect of weather parameters on radiation use efficiency in wheat crop

A field experiment was conducted during rabi season 1998–99 to study the effect of weather parameters (sunshine hours, vapour pressure deficit, maximum, minimum and mean temperatures, and relative humidity) on radiation use efficiency in wheat. Five cultivars V₁ (WH 542),V₂ (PBW 343), V₃ (UP 2338), V₄ (Raj 3765) and V₅ (Sonak) were sown on three dates i.e. 25^th November, 10^th December and 25^th December. Delay in sowing from 25^th November to 10^th December significantly reduced the radiation use efficiency. Efficiencies varied from 1.24 to 2.85 gm dry matter MJ⁻¹ of intercepted photosynthetically active radiation for wheat crop. Among varieties and sowing dates. Sunshine hours, vapour pressure deficit, maximum, minimum and mean temperatures of whole season were negatively associated while positive correlation existed for relative humidity with radiation use efficiel1cy.