The effects of glycine betaine on yield and yield components of sunflower(Helianthus annuus L.) in saline condition

To evaluate the effects of glycine betaine (GB) on yield and yield components of sunflower (Helianthus annuus L.) in saline condition, a field experiment was conducted in Islamic Azad university, Sabzevar Branch, in 2011. The experiment was carried out in factorial arrangement on the basis of a randomized complete block design with 3 replications. Factors were time of GB application at 3 stages (V5(5 leaves), R1 (forming of terminal bud) and R5 (beginning of flowering) and 4 GB rates (0, 50,100 and 150 mM).The results showed that foliar application of GB at V3 had the highest economic yield, biological yield and grain number in capitul. Delay in GB application increased potassium level in leaf. 100 seed weight was not affected by GB time application, although V5 had the highest 100 seed weight. Increase in GB rate increased linearly yield and yield components. 150 mM foliar application of GB had maximum yield and yield components. There was no significant difference between 100 and 150 mM foliar applications of GB. Na content increased 5.75% by increasing GB from 100 to 150 mM. Overall in saline conditions, 100 mM foliar application of GB at V5 was found to be the best treatment for achievement of maximum grain yield.