Effect of sowing dates on phenological development, yield and oil content of sunflower (Helianthus animus) in a Mediterranean-type environment

The effect of sowing time on phenological development, seed yield and oil content of sunflower (Helianthus annuus L.) was studied under the restricted irrigation conditions in Hatay, Turkey (36° 39’ N, 36° 40’ E) in 1998 and 1999. Sunflower cultivars (‘C 207’ and ‘Istranca’) were sown at 2-week intervals from 1 March to 15 July, with 2 supplemental irrigations. Delaying in sowing shortened the period for emergence, head initiation, and total duration. Seed yield increased until 1 April and then decreased greatly with further delay in sowing both cultivars. The higher oil contents were also recorded with earlier-sown sunflower crop.