Yield response of sunflower to water stress under tekirdag conditions

Abstract

This study was carried out to determine yield response factors (ky), under the conditions where 0%, 25%, 50%, 75% and 100% of the water requirement was supplied over the groving season. Relative water requirements were also supplied during the individual growth periods; namely, early vegetative, late vegetative, total vegetative, flowering and yield formation periods of sunflower (Helianthus annuus L) under Tekirdag conditions. In the experiment, total of 554 and 560 mm irigation water were applied and 799 and 762 mm seasonal evapotranspiration were measured in T1 treatment in which adequate irrigation water was applied during irrigated growing season in the year 1998 and 1999, respectively. The yield response factor (ky) was obtained as 0.85 for total growing season and 0.67, 0.43, 0.40, 0.28 and 0.20 for flowering, total vegetative, yield formation, late vegetative and early vegetative period, respectively. Flowering period was more sensitive to water deficit than the other periods.