Abstract: Effects of brassinolide on quality and stress tolerance of strawberry seedlings of four different varieties after foliar application in field under high temperature in summer. The results showed that brassinolide could significantly improve quality of Akihime strawberry seedlings， which showed high propagation coefficient and root activity. Significant changes were not observed in other varieties. Brassinosteroide significantly increased the stress tolerance of Benihoppe and Akihime strawberry seedlings due to low cell membrane permeability and MDA content. Similar changes were not showed in other varieties. APX activities of Benihoppe and Akihime were increase by brassinolide. However， CAT activities of Benihoppe， Toyonoka and Sweet Charlie were decreased after brassinolide treatment. Therefore， brassinosteroide can significantly improve the stress tolerance of Akihime and Benihoppe strawberry seedlings which have week tolerance.

Key words: brassinolide, strawberry, nursery quality, stress tolerance