Abstract: In order to accelerate seed dehydration process in hybrid rice seed production， different dehydrating agents were sprayed on seeds at dough stage in hybrid rice （cv. Qianyou NO.1） seed production in the field in summer， and the effects of different dehydrating agents and application concentrations on seed dehydration and quality of Qianyou NO.1 were studied. The results showed that all the 15 combinations of dehydrating chemicals could accelerate seed dehydration， and the moisture contents of seeds were decreased by 155%-835%， moreover， seed maturities were 1-10 days earlier than that of the control. Among 15 treatments， treatment No.7 had the best effect according to the germination parameters and 1 000-grain weight. Treatment No.7 not only had no negative effects on seed quality but also decreased seed moisture content for 246% and accelerated the maturation by 5 days. The results also showed that treatment No.7 could increase germination energy and germination index， improve seedling growth and POD activity， and decrease MDA content. It was suggested that treatment No.7 was a suitable seed dehytrating agent at dough stage for hybrid rice （cv. Qianyou NO.1） seed production.

Key words: hybrid rice production, dehydrating agent, moisture content, 1 000-grain weight, maturation