Agromet indices and response of varieties of wheat (Triticum aestvium) to sowing environments and nitrogen levels under irrigated lower hills of North-West plains of Shiwaliks

A field experiment was conducted during the winter (rabi) seasons of 2015–16 to 2016–17 at Agromet Research Farm, Chatha, Jammu and Kashmir (Union Territory), to evaluate the effect of weather parameters on phenology, agromet indices and yield of wheat (Triticum aestivum L.) varieties. Three wheat varieties (‘HD 2967’, ‘RSP 561’ and ‘WH 1105’), 3 sowing date or environments (25 October, 14 November and 4 December) and 3 N levels (100, 125 and 150 kg/ha) were laid out in split split-plot design with 3 replications. The results revealed that, wheat crop sown on 25 October (early) required more days to attain various phenological stages as compared to the crop sown on 14 November (normal) and 4 December (late). Temperature during the reproductive period had a significant effect on phenological stages of wheat and thus shortened the grain-filling duration. Early-sown wheat crop accumulated more growing degree-days (GDD), heliothermal units (HTU) and photothermal units (PTU) than normal and late-sown crop. Variety ‘WH 1105’ accumulated more values of agromet indices like GDD, HTU and PTU than ‘HD 2967’ and ‘RSP 561’. Higher temperature during reproductive phase showed negative relationship with grain yield of wheat. Simple regression and correlation between data showed that grain and biological yield of wheat had a highly significant relationship with (AGDD) at anthesis, milking and physiological maturity.