Genetic Analysis on the Sterility in Indica PGMRs HN5s

We obtained the two kinds of fertile mutants from the offsprings of the induced HN5s with the method of the combined treatment of the Co 60 γ irradiation, NaN 3(Sodium azide) and mature embryo culture. The one is the fertile revertant under the natural length day, high and low temperature. The other one is the male sterile under the natural length day, high temperature while is fertile revertant under the control length day, low temperature. To study the genetic behavior of male sterility in the Photoperiod Sensitive Genic Male Sterile Rice (PGMRs) line HN5s by utilizing the fertile revertants, we made the revertants self pollenated, test cross between the HN5s and its fertile mutants and identified the male sterility of the offsprings of the crosses and self pollenates under the control photo thermal conditions It was showed that the male sterility in HN5s was due to the two pairs recessive allele, a pair of male sterile gene with strength express and a pair of male sterile gene with weak express. When the strength express male sterile gene was induced into the weak express male sterile gene, the PGMRs was changed into Thermal Sensitive Genic Male Sterile Rice (TGMRs). The stability of the male sterility of PGMRs was related with the sensitive of the male sterile to the mutagenic factor. In addition, this paper stresses on the question of the causes of the undulation in male sterility of PGMRs and how to breed a stable PGMRs.