Relative Temperature Disparity and Wheat Yield as Influenced by Sowing Environments and Genotypes in Tarai Region of Uttarakhand

A temperature factor relative temperature disparity (RTD) was accredited satisfactorily signifi- cant with the sowing environments, having the range between 55.13 and 73.37 in Pantnagar, Uttarakhand. To accomplish the present requirement field experi- ments were carried out during the winter season of 2007-08 and 2008-09 at Pantnagar (29 o N, 79.29 o E with 243.80 m above msl) in split plot design (SPD) with six replications by means of three dates of sowing i.e. November 20, December 15 and January 9 in alliance of two wheat genotypes (viz. PBW-343 and WH-542). Genotype PBW-343 recorded highest grain yield, RTD values in corporation of recorded maximum number of days to achieve various phenophases followed by the genotype WH-542 in both the years. The value of RTD was increased from emergence to jointing stage and reached at higher with maximum vegetative phase, moreover, decreased from flowering to the maturity of the crop during study period. Higher value of RTD was found with early to mid sown crop, while it was decreased with the delayed of sowing (late sowing). Crop sown on 20 November produced highest yield of 4,580.3 and 4,080.3 kg/ha in 2007-08 and 2008-09, respectively. Due to delay in sowing environments with every 25 days reduction in yield was accredited by 13 to 26.1 and 14.6 to 29.3% in the year 2007-08 and 2008-09, respectively.