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Amidst climate change and declining water resources, deficit irrigation has become pivotal for water conservation in agriculture. The osmoregulators offer an innovative approach to enhance crop adaptation and productivity under abiotic stress conditions especially for global crop like wheat.

Therefore, the study was conducted during rabi 2022-23 and 2023-24 at MARS, Dharwad, to understand the response of dicoccum wheat to deficit irrigation and osmoregulators under different sowing dates.

The experiment utilized strip-split plot design with three sowing windows (D1: November II fortnight, D2: December I fortnight, D3: December II fortnight) as main-plots, two deficit irrigation levels (I1: Irrigation at 1.0 ETc, I2: Irrigation at 0.5 ETc) as sub-plots, and four osmoregulators as foliar spray treatments (O1: Salicylic acid @ 200 ppm, O2: Thiourea @ 400 ppm, O3: Kaolin as antitranspirant at 5%, O4: Water spray (at tillering and ear-emergence stage) as sub-sub plots and replicated thrice.

The pooled data revealed that, November II FN sowing window recorded significantly higher grain yield (3708 kg ha-1), dry matter production at harvest (108 g at 0.3m row length), test weight (37.50 g), flag leaf area (FLA) of 17.60 cm2 and membrane stability index (MSI) of 76.5% compared to other sowing windows. Similarly, irrigation at 1.0 ETc recorded 19.56 per cent higher grain yield, higher FLA and MSI over 0.5 ETc.

The root length increased by 16 per cent in 0.5 ETc irrigation indicating deeper proliferation of roots in search of water. However, the grain yield was significantly higher with thiourea @ 400 ppm (3170 kg ha-1) and salicylic acid @ 200 ppm (3068 kg ha-1) over water spray (2735 kg ha-1).

Thiourea recorded significantly higher FLA (16.42 cm2) and test weight (36.97 g). The interaction effect of D1×I1×O2 saved water by 45 per cent over recommended irrigation practice (560 mm) with higher productivity.

Keywords: ETc (Crop evapotranspiration), Osmoregulators, deficit irrigation, flag leaf area (FLA), Membrane stability index (MSI)