Unraveling the influence of sowing dates, deficit irrigation levels and osmoregulators on dicoccum wheat: A regression approach to relate yield and associated parameters

The study investigated the influenced of sowing date, irrigation levels and osmoregulators on dicoccum wheat during rabi 2022-23 and 2023-24 at Main Agricultural Research Station, University of Agricultural sciences, Dharwad. The experiment was laid in strip split plot design with Main plots viz., D1: November II fortnight sowing D2: December I fortnight sowing and D3: December II fortnight sowing, sub-sub plots viz., I1: Irrigation at 1.0 ETc and I2: Irrigation at 0.5 ETc and sub-sub plots viz, O1: Salicylic acid @ 200 ppm, O2: Thiourea @ 400 ppm, O3: Kaolin at 5% and O4: Control (Water spray) at tillering and ear emergence stages. Among the sowing dates, November II fortnight sowing recorded significantly higher flag leaf area, test weight and grain yield over other sowing dates. The deficit irrigation at 1.0 ETc recorded 16.05, 5.17 and 24.30 per cent higher flag leaf area, test weight and grain yield over 0.5 ETc which recorded 54.78 per cent higher chaffy grains spike-1. Among the osmoregulators, thiourea @ 400 ppm and salicylic acid @ 200 ppm at tillering and ear emergence stages recorded significantly higher grain yield and test weight. The chaffy grains were significantly higher in water spray (1.86). The interaction of November II fortnight sowing, irrigation at 1.0 ETc and foliar spray of thiourea @ 400 ppm recorded significantly higher flag leaf area, test weight and grain yield. The chaffy grains spike were significantly higher in December II fortnight sowing, irrigation at 0.5 ETc and water spray. Similar results were obtained with salicylic acid sprayed dicoccum wheat under November II fortnight sowing and 1.0 ETc irrigation. The regression analysis revealed a strong positive influence of flag leaf area and test weight on grain yield. In contrast, chaffy grains spike-1 showed a negative relationship emphasizing their detrimental impact on yield. Optimal sowing in November II fortnight, irrigation at 1.0 ETc, and foliar application of thiourea @ 400 ppm or salicylic acid @ 200 ppm significantly enhance flag leaf area, test weight, grain yield and decreased chaffy grains in dicoccum wheat which are strong determinants of grain yield.