The Ecological And Genetic Study Of Thermo-sensitive Genic Male Sterile (TGMS) Lines In Maize And Mapping The Genes For TGMS

This paper studied the thermo-sensitive genic male sterile lines Qiong6Qms and Qiong68ms in maize. The mechanism of fertility conversion of thermo-sensitive genic male-sterile line Qiong68ms in maize was studied by the methods of sowing by stage. During the sterile stage, individual fertility of the segregating population for (Qiong6Qms×Dan958) and (Qiong68ms×K12) were evaluated to study the genetic mechanism of the TGMS. The markers that were tightly linked with the TGMS lines Qing6Qms were selected by bulked segregation analysis (BSA). The molecular linkage maps for (Qiong68ms×K12) F₂ were constructed using the F_2:3 population, and the quantitative traits loci for fertility were detected. Fine mapping for sterile gene in Qiong68ms was constructed based on the results of QTLs and fertile separation of F₂ and BC₁. The objective of this study was to find the SSR markers that tightly link with the TGMS genes and constructe a system of marker-aided selection (MAS) that suited to select target gene and background.The ecological study showed that the daily maximum temperature was the critical factor of fertility conversion of the genic male-sterile line Qiong68ms. It was fertile under low temperature and sterile under high temperature. The temperature boundary of fertility was 30³3℃. When the maximum temperature was higher than 33℃, it represented sterile. On the contrary, it was fertile when the maximum temperature was lower than 30℃. The results of F₂ and BC₁ fertility separation ratio of (Qiong6Qms×Dan958) was 15:1 and 3:1, respectively. This showed that the male-sterility of Qiong6Qms was controlled by two recessive duplicated genes, they were named tmsl and tms2, respectively. The male-sterile genes tmsl and tms2 were primarily located on chromsome3 and chromosome5. On the chromosome3, tms1 linked with SSR primer umc2050 and bnlg1605, of 3.07 bins and their genetic distance was 7.9cM and 4.1cM, respectively. The tms2 gene was located on 5.03 bins linked with umcl416, umcl692 and umcl355, umcl274 with the distance of 10.0cM, 13.8cM, 1.1cM and 9.3cM. QTL analysis for the fertility of (Qiong68ms×K12) F_2:3 generation showed that there was only one major QTL related with fertility on 2.07...