Response of Barely Varieties to Drought Stress Imposed At Different Developmental Stages

This study was carried out to examine the response of 14 barley varieties to drought imposed at different developmental stages (DDS). To examine the effect of drought stress (DS) on germination rate and seedlings growth, the seeds were exposed to induced osmotic potentials (OP; -0.75 and -1.2 Mpa), in addition to the control. Er/Apm variety did not show any significant decrease in germination rate in response to OP. The most drought tolerant varieties at seedling stage were Morocco9-75, Yarmouk, Acsad 176, and WI2291 with minimal biomass losses. Varieties were also tested against four DS treatments: continuous DS (Dcon), early DS (Dearly), late DS (Dlate) and a combination of Dearly and Dlate (Dearly+late) treatments. Grain yield in the control treatment (continuous irrigation) was almost two times greater than Dcon treatment, while the reductions in Dearly, Dlate and Dearly+late treatments were 12.9, 26.1, and 33.6% compared to the control treatment, respectively. WI2291 and Yarmouk showed the minimal grain yield losses in response to DS at DDS and their ranks in response to DS remained almost unchanged at DDS, and consequently they could be considered as a potential source of genes for drought tolerance.