Twelve selected barley genotypes were evaluated under three irrigation regimes to
study their response to water stress at the Agric. Exp. Station. King Saud University
Riyadh. Saudi Arabia. The genotypes under study consisted of 4 new varieties
selected from KSU breeding program, 7 introduced varieties and the recommended
cultivar Justo. The three irrigation regimes were scheduled according to the
cumulative pan evaporation of 30, 60 and 120 mm and the total amount of water
applied during the season was 5000 rn' (W,). 3000 m' (W2) and 1500 m' 0113). The
three water regimes were assigned to main plots while the 12 genotypes were
allocated to sub- plots of a split plot deSign with 3 replications and the experiment was
conducted during 98/1999 and 199912000 seasons. Moisture stress significantly reduced grain yield, days to heading. days to maturity,
grain filling period and grain filling rate. Also the differences between genotypes were
highly significant. The irrigation regime x genotype was highly significant indicating
differential responses of genotypes to water stress. The linear regression coefficients
of genotype means on amount of pan evaporation were Significantly negative while
four coefficients were not significant. The latter group was considered tolerant;
however they were low in yield. Two genotypes were identified as tolerant to water
stress. Grain yield was highly correlated with grain filling rate only.