evaluation of genetic diversity in breeding genotypes of sainfoin under salt conditions

sainfoin (onobrychis sativa), a forage legume, is worth attention because of its production and superior quality among pasture and hay forage crops in iran. sainfoin forage yield may be reduced by different levels of salinity. increasing forage yield in saline environments through plant breeding could partially compensate for this shortcoming if sufficient genetic diversity and heritability be available under stress. this experiment was conducted to evaluate forage yield and agronomical attributes, estimate genetic parameters and determine superior genotypes for salt tolerance in advanced breeding projects. thirty genotypes were evaluated using a randomized complete block design during 2005 and 2006. results showed that there are significant differences among genotypes for yield and some morphological traits indicating a broad genetic variation in this germplasem. genotypic coefficients of variability for forage yield and for the number of stems were highest during the first year, while these coefficients were highest for number of stems and panicle per plant during the second year. the highest estimates of heritability were observed for powdery mildew susceptibility and plant height, while the lowest were for days to seedling emergence and canopy diameter. applying cluster analysis to the studied attributes, three groups were obtained which the most tolerant genotypes and the least similar accessions were identified to be further employed in the future breeding projects. finally, it can be concluded that there are sufficient genetic diversity and heritability for yield and other related traits in the studied sainfoin germplasem grown under salt environments indicating the efficiency of selection methods for developing tolerant varieties.