Effects of Foliar Rates of Methanol Applications on some of Traits Related to Seed Yield of Sunflower (Helianthus annuus L.) under Water Deficit Stress

Subject Areas : Journal of Crop Ecophysiology

E. Khalilvand Behrouzyar ¹ (Staff member, Department of Agronomy, College of Agriculture, Tabriz Branch, Islamic Azad University, Tabriz, Iran)
M. Yarnia ² (Associate Prof. Department of Agronomy, College of Agriculture, Tabriz Branch, Islamic Azad University, Tabriz, Iran)
E. Farajzadeh ³ (Staff member, Malekan Branch, Islamic Azad University, Malekan, Iran)
M. Herischi ⁴ (Msc. Student, Department of Agronomy, College of Agriculture, Tabriz Branch, Islamic Azad University, Tabriz, Iran)

Received: 2013-11-06 Accepted : 2014-06-01 Published : 2014-06-22

Keywords: Foliar application, Methanol, Sunflower, Water deficit stress,

Abstract :

To investigate the effects of rates of methanol foliar applications under water deficit stress on someof traits related to seed yield of sunflower (Helianthus annuus L), a split plot experiment was conducted during growing seasons of 2011-2012. Treatments were four levels of water deficit stresses a1: severe stress (irrigation at 25% FC), a2: mild stress (irrigation at 50% FC), a3: fair stress (irrigation at 75% FC) and a4: normal irrigation (irrigation at 100% FC) and six levels of foliar methanol applications [b1:0, b2:7, b3:14, b4:21, b5:28 and b6:35 (v/v)]. The analysis of variance showed significant effect of interaction between water deficit stress and methanol rates of foliar applications on seed yield per plant, dry weight per plant, number of seeds per head (p<0.01) and percentage of seed per fruit (p<0.05). The highest (96.69 g/plant) and the lowest (67.78 g/plant) seed yields were related to the 21% [v/v] foliar application of methanol under normal irrigation and control (without methanol application) in severe stress respectively (seed yield increase of about 42%). 21% (v/v) foliar application of methanol under normal irrigation also resulted in highest ( 53.34 g) and 0% (v/v) foliar application of methanol under severe stress in the lowest (31.42 g) oil yield per plant (69% increase). Also, 21% (v/v) foliar application of methanol under normal irrigation resulted in highest (465.4 g) and in severe stress had the lowest (191.5 g) dry weight per plant (a 2.4 fold increase in dry seed weight). Besides,the highest seed number per head was related to 21% (v/v) methanol foliar application under normal irrigation. Using 21% (v/v) methanol foliar application under normal irrigation increased seed number per head by 2/3 times in comparison with that of control under severe drought stress. The results also proved that 14% (v/v) foliar application of methanol under normal irrigation did increase seed (achene) yield by 32% and reduced percentage of ovary wall to seed by 2/1 fold.