The Effects of Water Deficit Stress on Some Morphological Characteristics and Grain Yield of Armavirsky Cultivar Sunflower (Helianthus annuus L.)

Abstract

To investigate the effects of water deficit on some morphological characteristics and grain yieldof Armavirsky sunflower cultivar, an experiment in a randomized complete block design was conducted in Research Station of Islamic Azad University, Tabriz branch with three replications. Five levels of drought stress consisted: (D1=50, D2=100, D3=150, D4=200 and D5=250 mm evaporation from class A evaporation pan). Results showed that grain yields were 5486, 4480, 3080, 2460 and 2260 kg per hectare for D1 to D5 respectively. Increasing water deficit levels decreased grain yield, oil percentage, no. of grain per head, 100 seed weight, dry weight, stem diameter, head diameter, leaf area index, relative water content, chlorophyll content. While increased adaixial stomata number, percentage of empty seed and stomatal resistance. However, the differences between D1 and D2 were only significant for 100 grain weight, empty seed percentage, and no. of grain per head; It seems that these traits begin to increase after flowering; thus, if can be suggested that early irrigations of Armavirsky up to flowering may be carried out by D2 and then after by D1 levels to optimize seed yield and prevent significant decrease in other attributes.

Keywords

• cultivar
• Grain yield
• Oil Percentage
• Sunflower
• Water deficit