germination and seedling growth properties in triticale (triticale hexaploide lart) genotypes under effect of different water potential caused by salinity and drought

both poor germination and crop establishment due to water stress and salinity are among the most important limitations for production in semi-arid regions such as iran. to evaluate the response of four genotypes of triticale (et-82-15، et-82-8، et-79-17 and juanillo-92) to different water potentials caused by salinity and/or drought and recognizing the germination and seedling establishment, a study was carried out based on factorial completely randomized design with three replications in 2008.salt treatments consisted of 0, 0.5, 1, 1.5 and 2 percent of nacl solution(equal to 0, -3.8, -8.5, -11.6, and -14.8 bar, respectively) and drought treatments consisted of 6 levels of 50, 100, 150, 200, 250 and 300 gr peg per 1 liter distilled water(equal to -0.5, -1.48, -2.95, -4.91, -7.36 and -10.3 bar, respectively). results showed that negative water potential caused by salinity and drought treatments had significant effect on percentage of germination. with decreasing the water potential, percent of germination was reduced similarly in same water potential until -7 bar, reduction of germination percentage was lower in drought rather than salinity. cultivar juanillo-92had the highest and genotype et-82-8 the lowest germination under drought and salinity conditions. similarly, rate of germination was reduced with decreasing water potential, and in the same water potential until -7 bar rate of germination in drought condition was higher than salinity. in lower water potential (-10 bar) in drought treatment, seed germination of triticale was halted, while this trend in salinity treatments was continued until -15 bar. differences between percent of germination in genotypes under salinity at 0.01 % probability level were significant, but under drought stress was not significant. finally, based on ranking of genotype with measurement characteristics, salinity tolerance was: et-82-8 < et-79-17< et-82-15< juanillo-92.also, despite of similar drought tolerance of genotypes, cultivar juanillo-92 was relatively more tolerant to drought under these conditi