Study of oil yield variation under sowing date and plant density effects in sunflower (Helianthus annuus L.)

Sunflower requires favorable environmental conditions during plant vegetative growth and reproductive development stages to produce optimum yield. To study how oil sunflower seeds were changed by planting date and density, an experiment was conducted in a split plot as base of randomized complete block design in Seed and Plant Improvement Institute for two years. Planting dates interval were 21 days including of 19 May, 9 June, 0 3 June and 20 July and plant densities as 6, 8, 10 and 12 plants.m-2, set in main and sub plots, respectively. The results indicated that the year was not significant in measured traits except of total dry matter. Planting date had significant difference on all traits except of harvest index. Seed oil yield and TDM were affected by plant density at 1% probability level, but it had not significant effect on seed oil percentage and harvest index. Interaction of planting date and density was significant only on TDM. Therefore, planting date between May 19 to 9 june and 12 plants.m-2 was appropriate to get the optimal oil yield for sunflower new hybrid, CMS- 26 ÍR-103.