Sowing time and irrigation scheduling effects on seed yield and fatty acids profile of sunflower in semi-arid climate

A research was conducted in Southern Italy to study the changes in seed yield, oil content and fatty acids composition, in response to irrigation at different stages of growing season (at sowing, Dry; from sowing to beginning of flowering, S-BF; from visible bud to 75% flowering, VB-FF; from beginning of flowering to seed ripening, BF-M; from sowing to seed ripening, Full), in a standard sunflower hybrid sown at normal (April) and late (June) time. High seed yield and oil content combination resulted in the significantly greatest oil yield in ‘Full’ water regime. MUFAs (mostly oleic acid) were higher in late sowing and they benefit from good soil water availability of ‘Full’ regime. Contrastingly, PUFAs (i.e. linoleic acid content), higher in late season, was depressed by good soil availability during the early growing season (S-BF and S-M regimes). Irrigation at critical stages (i.e. flowering) may alleviate the negative impact of water stress upon crop productivity and oil fatty acids composition, resulting in yield and oil quality benefits besides a water saving. Late sowings allow cultivating sunflower as a catch crop, with an increased economic and environmental sustainability of Mediterranean farming systems.