Abstract:The dormancy and germination of Brochypodium distachyon caryopses sampled from three populations in Israel were investigated. The results showed that caryopses of B. distachyon developed dormancy which was found not to be the type of exogenous dormancy. The factors, such as temperature and duration of dry storage, etc. had significant effects on caryopsis germination of B. distachyon. The afterripening process could accelerate and caryopses dormancy could break when storaged at high temperature (40℃), and the order of dormancy depth among three populations was Sede Boqer > Yatir > Mt. Carmel. Furthermore, the dormancy depth was found to be correlated negatively with the mean annual rainfall at three local sites. The present results demonstrated that evolutionary background has a strong effect on the intensity of caryopses dormancy of this species, and B. distachyon populations have evolved adaptive mechanisms by regulating the time of germination in Israel.