Studies on Seed Dormancy in Photoperiod-and Thermo-sensitive Genetic Male Sterile Line Xin'an S in Rice

Using the seed of Xin′an S harvested in spring from Hainan as the material,the seed dormancy characteristic,the mechanism of seed dormancy and the effective methods of breaking seed dormancy of Xin′an S were studied by continuously and termly testing the germination of the dormant seed in its storage period under low or normal storing temperatures and testing its germination after the treatments of various physical and chemical methods.The results showed that there was a characteristic of deep dormancy in the seed of Xin′an S,and the dormant period of its seed(with a germination percentage less than 80%) was 47~62 days.The hull was one of the main causes resulting in the seed dormancy.The activity of α-amylase in the dormant seed was lower than that in the undormant seed.The treatments of high temperature(45℃,4 d),dehulling,and soaking seed with appropriate concentrations of HNO3,GA3,H2O2 and trichloroisocyanuric acid solution were effective to break the seed dormancy of Xin′an S.