Studies On The Main Characteristics Of Photo-thermo-sensitive Genic Male Sterile Lines, M113S And Hua201S

The two-line hybrid rice based on photoperiod-sensitive genic malesterile (PGMS), thermo-sensitive genic male sterile (TGMS) and photo-thermo-sensitive genic male sterile (PTGMS) rice is a significant innovation of the hybrid rice breeding. The key point in the two-line hybrid rice breeding program is to develop some PGMS or TGMS lines with both stable sterility and strong combining ability. Although some two-line hybrid rices with strong heterosis have been bred by Chinese breeders in past years, there are still many difficulties to be solved urgently.Two PTGMS sterile lines, M113S and Hua201S, were used in the study. The characteristics of fertility alteration were investigated through continous interval sowing at Wuhan and rationing at Lingshui, Hainan, with Peiai64S as the control. To study the genetic behavior, we analyzed the pollen fertility, self seed setting and natural seed setting of F₁, F₂ and BC₁ from crosses between two male-steriles lines and 6 conventional varieties. The allelomorphism of sterile genes among genic male sterile lines was analized. In addition, the classification of indica-japonica was studyed by molecular method. M113S and Hua201S were tested with more than 80 varieties, respectively. Some heterotic combinations were selected through the analysis of hybrid performance on yield per plant and important agronomic characters. The results are are as follows:1. Results of the characteristics of fertility alteration indicated that the sensitive stage to temperature and sunshine of different PTGMS sterile lines was different. The decision coefficient about temperature and the sunshine were also different. The sensitive stage of M113S was from 13 days to 25days before heading, that of Hua201S was from 14 days to 25s day, that of Peiai64S was from 13 days to 22days. The results of the fertility inspections at Wuhan and at Lingshui showed that Hua201S was more stable had lower critical temperature point of fertility alteration, comparing with M113S and Pei-ai 64S.2. The identification in the artificial climate chamber indicated that the critical temperature point of fertility alteration in M113S was about 23.5℃.3. The inheritance analysis results indicated that the sterility of male-sterile line was controlled by recessive genes. The curve diagram of fertility segregation in 6 F₂ populations appears to be suited for bi-peak and multi-peak model. The position and height of the fertility peak and sterility peak were different. It suggested that expression of the male-sterility gene was different. Fertilities of F₂ and BC₁...