Physiological response of sunflower (Helianthus annuus L.) to foliar application of methanol under water deficit stress

In order to investigate the effect of water deficit stress and methanol foliar application on yield and yield components of sunflower (Helianthus annuus L.), an experiment was conducted in the split plot form based on completely randomized block design with three replications during growing seasons of 2011-12. Treatments were water deficit stress in four levels : a(1) : severe stress (25% FC irrigation), a(2) : mild stress (50% FC irrigation), a(3) : fair stress (75% FC irrigation) and a(4): normal irrigation (100% FC irrigation) and the foliar application of methanol in six levels [b(1) : 0, b(2): 7, b(3): 14, b(4): 21, b(5): 28 and b(6): 35 (v/v)]. The analysis of variance showed significant effect of interaction between water deficit stress and methanol foliar application on Chl. a and Chl. b content, total Chi. a+Chl. b, RWC, seed and oil yield/ha (P<0.01). The detailed results of the study showed that foliar application with 21% (v/v) methanol in 50% FC irrigation and had 9, 20 and 16% more Chl. a and Chl. b content and total Chi. a+Chl. b than without methanol spraying in mild stress treatment, respectively. Besides, the results also proved that 21% (v/v) methanol foliar application in normal irrigation had 7735 and 4267 kg/ha seed and oil yield.