Effect of Planting Date on Yield, Plant Water Stress Index and Water Usage Rate of Sunflower (Helianthus Annuus) Genotypes in Semi-Arid Cukurova of Turkey

Abstract

The aim of this study is to identify the effect of the different sowing dates on the sunflower efficiency and the efficiency of elements, plan t water consumption, plant water stress index and water usage rate. The study was conducted to determine the effect of the different planting dates on yield and the yield components of 6 sunflower genotypes in the semi-arid Cukurova region of Turkey, all through the periods of the year 2012 to 2013. In this research, two different planting dates were examined and Evapotranspiration (ET), as the average of two years in the first and second growing seasons was found to be 567 mm and 578 mm, respectively. On at wo years average, the amount of irrigation water was determined as 524 mm. ET, Water Use Efficiency (WUE), Irrigation Water Use Efficiency (IWUE), Chlorophyll Content (CC), Crop Water Stress Index (CWSI), and grain yield were significantly affected. Results showed that thermal stress accelerated flowering and physiological make-up time. The highest CWSI values were determined as 0.67 in genotype No.1 and the lowest values are between genotypes No.4 or No.5,which is given as 0.22 and 0.27 respectively.