Agro meteorological Indices of Wheat (Triticum aestivum L.) crop under varying thermal regimes and moisture levels

A field experiment was conducted to investigate the relationship between agrometeorological indices and the grain yield of wheat cultivar HD-2967 under varying thermal regimes and moisture levels at Acharya Narendra Deva University of Agriculture & Technology, Kumarganj, Ayodhya (U.P.) during the Rabi 2022- 23 and 2023-24. The main plot treatment consisted of with three thermal regimes or sowing dates (D1: 15th November, D2: 25th November, D3: 5th December) in sub plots four moisture levels (I1: CRI, I2: CRI + tillering, I3: CRI + jointing and milking, I4: CRI + jointing + anthesis and dough stage). Data of two Rabi 2022-23 and 2023-24 seasons was pooled to conduct analysis. D1 (15th November) thermal regime exhibited the highest yield 47.5 q/ha followed by D2(45.0 q/ha) and lowest (36.9 q/ha) at D3. Moisture level showed highest 46.9 q/ha and I140.2 q/ha showed the lowest yield. Maximum heat use efficiency was observed under D1(3.30 kg/ha/0 C days) followed by D2(2.80kg/ha/0 C days) and least at D3 (2.34kg/ha/0 C days) and among the moisture levels highest use efficiency was recorded at I4 moisture levels (2.41 kg/ha/0 C days) followed by I3(2.34kg/ha/0 C days), I2 (2.33kg/ha/0 C days) and least at I1(2.27kg/ha/0 C days). Early sowing (D1: 15th November) and moisture level I4 consistently resulted higher values of agrometeorological indices, which were positively correlated with grain yield. Accumulated growing degree days and accumulated photothermal unit had the strongest correlation with grain yield (0.84 and 0.74), respectively. Accumulated heliothermal unit and accumulated pheno-thermal index, while positively correlated, had a relatively weaker association (0.56 and 0.32), respectively, with grain yield.