Deficit irrigation of s unflower under Mediterranean environmental conditions

This work aims at: analyzing response of sunflower crop to several irrigation water regimes and evaluating the suitability of sunflower to deficit irrigation strategies. An open-field trial on hybrid Sanbro_MR was carried out at experimental fields in Valenzano (Bari, Southern Italy), characterized by semi-arid Mediterranean climate and clay-loamy soil. The experiment includes five irrigation regimes: optimal water supply, application of 100% of water requirements up to flowering and 70% thereafter, application of 70% of water requirements through the whole season, application of 70% of water requirements up to flowering and rainfed conditions thereafter, and rainfed conditions during the whole season. Sunflower response to water supply and intensity, timing and duration of water stress was investigated by means of leaf area index (LAI), radiation interception, biomass production, water consumption, yield, water use efficiency (WUE) and radiation use efficiency (RUE). The overall results indicate deficit irrigation as an acceptable strategy for sunflower highlighting the importance of irrigation between flowering and maturity.