Abstract: The sterility segregation and its genetic patterns of indica P(T)GMS rice were analyzed mainly based on the investigation of bagged seed set of individuals in reciprocal F₂ population from the crosses between P(T)GMS lines of different origin and typical indica conventional varieties of different ecotype under long day length and high temperature condition by using the software of the maximum likelihood method. The results showed that the sterility of Annong S-1,Hengnong S-1,and W6154S,of which the sterility alteration was mainly induced by temperature fluctuation,was controlled by one major recessive gene. But the sterility of W7415Swas controlled by more than two major recessive genes. Apart from the major recessive gene,there was a group of polygenes in controlling of the sterility segregation in F₂ population. Moreover,the polygenic variance was different from line to line. It implied that the polygenes of W6154S or W7415Swas far more complicated than that of Annong S-1 and Hengnong S-1 according to the maximum likelihood method. All the conventional indica varieties of different ecotypes possessed the major dominant fertility genes. Meanwhile,the genetic background in different ecotype conventional varieties,the essentiality of which lies in the existence of polygenes,was different and influenced the major gene expression deeply. It was also indicated that genetic background of middle season variety Nanjing11 was more complicated than that of early season variety Erjiuqing and late season variety GER 1 as well. Finally,the differences of drift in critical temperature inducing male sterility of P(T)GMS lines (for short term DCT) and the stratgey of breeding practically usable P(T)GMS line with slighter DCT were discussed in the paper.

Key words: Indica rice, P(T)GMS, Genetics, Maximum likelihood method