Study of water deficiency levels on ecophysiological characteristics of sunflower cultivars in Isfahan, Iran

Abstract

This study was aimed to investigate the effect of drought stress on some ecophysiological characteristics of sunflower cultivars. This study was conducted in the form of split plots in a randomized complete block design with three replications in the Braun area of Isfahan province for the year 2020. Drought stress at three irrigation levels after evaporation of 90, 120, and 150 mm from Class A evaporation pan as non-stress, mild, and severe stress, respectively, in the main plots and five cultivars of sunflower Chiara, Oscar, Fantasia, Hisun 33, and Shams was placed in the subplots. Drought stress affected achene yield, harvest index, and drought tolerance of sunflower cultivars. The highest biophysical water productivity (WPb) was obtained from 90 and then 120-mm irrigation and among sunflower cultivars from Fantasia and Hisun 33 cultivars. The highest economic water productivity (WPe) was obtained with 90-mm irrigation and Fantasia and Hisun 33 cultivars. The highest HI belonged to 90 and then 120-mm irrigation. The highest HI was related to Fantasia, Oscar, and Hisun 33 cultivars, and the lowest HI was related to Shams and Chiara cultivars. The highest and the lowest grain yield were obtained in 90 (control) and 150 mm of evaporation, respectively. The highest grain yield was obtained in Fantasia, Shams, and Oscar cultivars, and the lowest yield was observed in Hisun 33 and Chiara cultivars. In general, drought stress affected yield, HI, crop water productivity (WPc), and drought tolerance of sunflower cultivars.