Effects of sowing date on sunflower (helianthisannuus l.) yield and yield components under rainfed conditions in blue nile state,

A field trial was conducted for two consecutive seasons (2014/15 and 2015/16) at Al- Damazin Agricultural Research Station Farm, Damazin, Sudan, located at longitude 34°22’ E, latitude 11°47’ N and altitude 470 m. The objective of this study is to determine the optimum sowing date for sunflower under rainfed conditions in Blue Nile State, Sudan. The experimental materials consisted of one sunflower hybrid (Sirena cultivar) and four sowing dates late-July (22 and 24 July), early August (1 and 3 August), mid-August (11 and 13 August) and late August (21 and 23 August). The experiment started grown on 22.7.2014 and 24. 7. 2015 as the first sowing date with interval period of 10 days between each sowing date to other. A randomized complete block design with three replications was used. Data collected and parameters measured included days to 50% flowering, days to maturity, plant height (m), head diameter (cm), 100 – seed weight (g), % of filled seed and seed yield ton/ha. Statistical analysis revealed highly significant differences (P≤ 0.001and P≤ 0.05) among all traits measured in both seasons. Seed yield recorded the highest value (2.8ton/ha) in season one by the late July (21-23) sowing date. The combine analysis for seed yield over the two seasons revealed that the early August (1-3) sowing date out-yielded (2.6tons/ha) the rest tested sowing dates.