Screening of barley genotypes for drought tolerance by agro-physiological traits in field condition

In a two-year experiment, 11 barley genotypes from ICARDA and one landrace from Iran were tested under optimum and drought stress conditions. Phenological and physiological traits such as relative water content (RWC), osmotic adjustment (OA), stay-green (SG), plant height (PLH), days to heading (DHE), days to maturity (DMA) and seed indexes such as 1000-grain weight (TGW), number of grain per spike (G/S) and grain yield (GY) were evaluated. Variations were observed in DHE, DMA, G/S, TGW, PLH, RWC, OA and length of stay-green period. DHE and DMA were the phenological traits that most influenced yield during water stress conditions. Negative correlation was observed under water stress between yield, DHE, and DMA under drought stress. The average reduction in yield caused by drought stress was 28.05%. Under drought stress condition, TGW, G/S, RWC and SG correlated positively with yield, while under both stress conditions, the correlation of yield and PLH was lower than other correlations. Yield was significantly correlated with osmotic adjustment (P<0.05). Among the genotypes, L6 possessed the greatest OA capacity, and L3, L8, L9 and L10 the smallest. The genotypes that show higher OA capacities therefore, are those that are most drought tolerant. Genotype L6 performed well under water stress condition as it attained a reasonable plant height, precocity, RWC, OA and SG, gave higher grain yields and seed index as compared with other genotypes.