Studies On The Characteristics Of Male Fertility Alteration And Genetics Of Photo-thermo-sensitive Genic Male Sterile Lines In Rice

The utilization of the hybrid vigor of rice is one of the main pathes in rice breeding. Two-line hybrid rice is one of the hybrid rice breeding methods. Two-line hybrid rice has been based on the photoperiod and thermo-sensitive genic male sterile (PTGMS) rice. Many scientists devote to the study of the two-line rice breeding and made great progress in the past two decades. But, there were still many vital problems to be unresolved, especially the genetic mechanism and gene molecular mapping. So it is important that the genetic mechanism of two-line sterile lines was illustrated and practical usable sterile lines were developed, which must bear a lower critical sterility temperature point (CSTP).Seven sterile lines were studied in the research. The characteristics of male fertility alteration were observed and analyzed. Genetic studies were made through F₁, F₂ and BC₁ population of 9 combinations which came from the incomplete double row hybrid among ID24, 810S, M61S, T1007, IR57301 and Shengyou No 2; Studies on allelism were analyzed among the ID24, 810S and M61S. The tms gene in ID24 was mapped using SSR markers. The results are as follows:1. The sensitive stage and CSTP of fertility alteration in seven lines were different. The sensitive stage of ID24 was from 19d to 10d before heading, the CSTP was 24.6℃; the sensitive stage of 810S was from 13d to 5d before heading, the CSTP was 24.7℃; the sensitive stage of M61S was from 16d to 0d before heading, the CSTP was 25.9℃; the sensitive stage of M201S were from 20d to 14d before heading, the CSTP was 25.3℃;the sensitive stage of M113S were from 20d to 15d before heading, the CSTP was 25.1℃; the sensitive stage of M102S was from 10d to 7d before heading, the CSTP was 24.0℃; the sensitive stage of M23S was from 24d to 8d before heading, the CSTP was 23.7℃.2. The fertilities of pollen, self- and natural seed sets in 9 F₁ generations between sterile lines and normal varieties were fertile, showing the sterile character controlled by recessive genes. Accept of combinations mated by M61S, the fertilities in other combinations were as similar as their male parents. T-tests showed that the fertilities in the combinations from three male parents crossed with same sterile line were different significantly in 5% level. The restoring ability was different in three male parent varieties. The restoring ability of T1007 was best, Shengyou No 2 was second, and IR57301 was third.3. The fertility segregations in 9 F₂ populations appeared to be suited for bi-peak...