effect of micronutrient fertilizers on sunflower growth and yield in drought stress condition

sunflower (helianthus annus l.) is the most important between oil plants in iran. the objective of this study was to evaluate the effects of micronutrients application on the sunflower yield under drought stress. this experiment was carried out at golmakan agriculture research station (iran) in 2005 that using a split plot randomized complete block design with four replications. irrigation was as a main factor at three levels (normal, low stress and high stress) and six micronutrient treatments were (control, fe, fe+zn, fe+zn+cu, fe+zn+cu+mn fe+zn+cu+mn+b) as sub plots within the main plots. base fertilizers (n, p, k) and micronutrient treatments also used as required on the basis of the soil test. results showed that the plant height, amount of chlorophyll in leaves, head diameter, seed per head and seed yield were significantly different between control and stress treatments. but irrigation treatments had no statistically significant effect on the flowering date, seed weight and oil percentage. results also showed that micronutrient treatments increased the head diameter, seed per head, seed yield and oil percentage. therefore, we confirm that under drought stress micronutrients application increases drought resistance in sunflower.