Evaluating productivity potential of spring planted sunflower (Helianthus annuus) hybrids in response to sowing time under changing climate scenario

A field experiments was conducted during the spring seasons of 200506 to 200708 at Ludhiana, Punjab, to assess the interaction between genotypic variability and modified environmental conditions in response to chang- ing sowing time for sustainable crop production in sunflower ( Helianthus annuus L.). Maximum harvestable yield was obtained when sunflower was sown in mid-January. Very early sowing (20 December) did not generate any advantage not only for the earliness but also for the yield components; however, later sowings (5 and 20 February) resulted in overall reduction in crop duration, poor seed setting, hastened maturity ultimately culminating in lesser sunflower yields. Cooler temperature prevailing during the initial crop establishment, particularly under the earlier sowing dates (20 December, and 5 January), imparted considerably longer seed emergence period. Sunflower hy- brid PSH 569 recorded the highest seed yield (2.06 t/ha), excelling SH 3322 by 3.5% and PSFH 118 by 13.8%. Correlation studies indicated stronger association for yield components and yield with the weather variables during flowering and seed-filling period, therefore, reveals a decisive factor to optimize sunflower yield by adjusting sow- ing time under changing climatic scenario.