All cultivars had good winter hardiness in xerothermic valley area. Big difference existed in summer hardiness. Millennium could survived 90.9%, Eureka, WL525HQ, WL323ML more than 80%, AlfaKing and Algonquin, 68.7% and 69.6% respectively.

• 供试的6个紫花苜蓿品种在干热河谷地区都能安全越冬；但越夏率差别大；盛世的越夏率高达93.；7%25；游客、WL525HQ的越夏率在90%25以上；苜蓿王、阿尔冈金、WL323的越夏率较低；分别为68