DEVELOPING HIGH-YIELDING BARLEY CULTIVARS UNDER DIFFERENT STRESS CONDITIONS IN EGYPT

Four groups of yield trials namely; Screening Yield Trial (SYT), Preliminary yield Trial (PYT), Advanced yield trial (AYT), and Demonstra­tion yield trial (DYT) were grown under different stress conditions during the 1995/96 growing season. The SYT experiment was grown in Ismailia (poor sandy soil under sprinkler irrigation) and Mallawy (high temperature and aphid infestation). The second experiment (PYT) was planted in six locations; Nubaria (calcareous soil), Sakha (disease problems), EI-Serw (saline soil), Ismailia, Mallawy, and the New Valley (heat stress). The third experiment (AYT) was planted in five locations; Ismailia, Mallawy, El­Mataana, Korn Ombo, and the New Valley. The fourth experiment (DYT) was planted in three locations; Ismailia, Nubaria, and the New Valley. Results showed that in SYT, remarkable variability in grain yield (GY) was observed. This variation ranged from 3308 to 5755 kg/ha. One genotype was superior to the check in both grain yield and biological yield (BY) in addition to straw yield (SY). In pyt, nine genotypes were significantly earlier than the national check ranging from 4 to 9 days ear­lier at Ismailia, whereas, at the New Valley, the majority of the geno­types were significantly earlier than the check. Two genotypes had rela­tively high BY, SY and GY. High potentiality of the New Valley area compared to Ismailia was observed. In AYT, six genotypes were signifi­cantly earlier than the national check at Ismailia. Regarding GY, only one genotype which had high BY and SY had also high GY with relatively low harvest index (HI) (0.255).. Heading date at the New Valley was much earlier than that of the other two locations with an average of 72 days to heading. The average plant height in the New Valley has also been af­fected by the temperature and due to the short duration of growth un­der this condition. On the other hand, By, SY, and GY at the New Valley were higher than the other two locations.