Agronomic Performance of Wheat Varieties in Relation to Sowing Dates in Shiwalik Range of Uttarakhand, India

Wheat (Triticum aestivum L.) plays a vital role in global agriculture, particularly in India, the world's second-largest producer. Despite its adaptability, wheat cultivation in regions like Uttarakhand faces challenges due to population growth, limited arable land and climate change threats. This study evaluated four wheat varieties (RR-21, SY-255, PBW-550, PBW-292) across three sowing dates (10th, 20th, and 30th December) using a Randomized Block Design during the 2023–2024 Rabi season at Dev. Bhoomi Uttarakhand University's agronomy research farm in Naugaon. The study measured key agronomic parameters including plant height, Leaf Area Index (LAI), Net Assimilation Rate (NAR), Crop Growth Rate (CGR), Relative Growth Rate (RGR), and yield components. Statistical analysis using ANOVA highlighted significant differences in growth and yield attributes among sowing dates and varieties. Sowing on December 20th exhibited superior performance, notably with variety RR-21 showing higher plant height, dry weight, CGR, LAI, RGR, and NAR. Variations in yield attributes such as grains per spike, effective tillers, spike length, 1000-grain weight, grain yield, stover yield, biological yield, and harvest index were also observed. Late sowing negatively affected germination rates, leading to increased weed competition and reduced growth parameters.