evaluation of iranian sainfoin ecotypes (onobrychis viciifolia scop.) under non-stress and drought stress conditions

drought stress is the main limiting factor in the arid and semi-arid region of the world. this research was conducted to evaluate drought tolerance in different accessions of sainfoin for yield, morphological and agronomic traits in 2010. twenty one accessions (landraces and varieties) were evaluated in two environments including drought stress and non-stress conditions for four harvests according to a split plot design in time. results showed that drought stress significantly decreased forage yield and yield components, while increased percentage of dry matter yield and leaf to stem ratio. the effects of drought however varied for different harvests. drought stress decreased genetic variability for most of the measured traits. in both moisture environments forage yield had the highest genetic variation. plant height and panicle length had the highest value of heritability (85 and 82 % respectively) and may be improved by direct recurrent selection. the results of mean comparison for non-stress condition showed that accessions kabotarabad, fereidonshahr and khansar2 had the highest forage yield while in drought stress condition accessions kabotarabad, fereidonshahr2 and janatabad had better performance. accessions arak and semirom in non-stress condition and arak, khansar, semirom and fereidoonshahr in the stress condition had the highest leaf to stem ratio. cluster analysis on the studied attributes produced several genetically distant accessions. accessions with more genetic distance may be used as appropriate candidates for developing new varieties in future breeding programs.