International Agricultural Congress, Van, Turkey, 9 - 12 May 2018, pp.251
In closing the oil import deficit of Iraq, sunflower is gaining importance as an oil-seed plant. On the bases of this point, this research was carried out during the successive seasons in 2015 to determine the effects of different humic acid (HA) doses (HA1: 0 kg HA da-1, HA2: 15 kg HA da-1, HA3: 30 kg HA da-1 and HA4: 45 kg HA da-1) on yield and yield components of sunflower (Helianthus annuus L.) varieties under farmers' conditions in Sulaymaniyah (Rania) district, Iraq. The study was conducted as split plot in randomized complete block design arrangement with three replications. The main plots of each replication were contained two varieties and sub-plots were contained four HA doses. HA doses had significant effects on all parameters except physiological maturity, harvest moisture and protein ratio of varieties. The interaction of HA doses and variety had significant effects on plant height, harvest index and seed yield. results, flowering time was 71.00-74.50 day, physiological maturity was 105.33-106.50 day, plant height was 155.57-164.23 cm, head diameter 19.98-23.17 cm, number of nodes 28.52-33.10 number plant-1, harvest moisture 16.03-18.04 %, harvest index 27.88-30.68 %, number of seed per head 1145.10-1282.43 number head-1, seed yield per plant 126.05-154.58 g plant-1, husk ratio 68.03-69.01 %, 1000 seed weight 68.58-71.91 g, seed yield 501.25-552.12 kg da-1, oil ratio 38.2040.33 % and protein ratio was 14.77-16.49 %. The maximum yield and oil ratio were obtained from Flame and Sirena varieties which interacted with HA3, as 555.63 kg da-1 and 41.45%, respectively.