Study On The Chromosomal Location Of The T-Type Restorer Gene And Linkage Analysis Between It And The K-Type Male Sterile Gene In T.Macha

Using heterosis is one of the important way to improve wheat yield. To enlarge the maintainer resources of K-type hybrid wheat, and to overcome the disadvantages of 1B/1R K-type male sterile line, He Beiru use T-type restorer gene Rf3 of T. spelta var. duhamelianum as the genetic marker of its K-type sterile gene rfv1, invented a method for breeding non-1B/1R K-type maintainer line and male sterile wheat line. According to previous study, similar to T. spelta, T. macha also has a T-type restorer gene and a K-type male sterile gene. But the location and the relationship between those two genes in T. macha was not defined so far. He Beiru supposed that those two genes may have linkage relationship. So the transfer of the K-type male sterile gene of T. macha into T-type CMS line TD₂3314A was conducted by using its T-type restorer gene as a genetic marker, the new non-1B/1R K-type maintainer line Tm3314 and its male sterile line KTm3314A was obtained. This method was applying Chinese Patent (CN200410025899.9).In order to define the chromosomal location of the T-type restorer gene and the relationship between the T-type restorer gene and the K-type male sterile gene in T. macha, experiments were conducted in 4 aspects: the non-1B/1R K-type CMS line KTm3314A with male sterile gene from T. macha and 1B/1R K-type CMS line was compared to define the potential of this non-1B/1R K-type CMS line in hybrid wheat production;The chromosomal location of the T-type restorer gene of Tm3314, which from T. macha, was studied by using monosomic and nullisomic analysis, and the allelism of the T-type restorer genes between Tm3314 and Tsp3314, the latter has T-type restorer gene from T. spelta, was studied;The linkage relation between the T-type major restorer gene and K-type major male sterile gene was analyzed to provide a foundation for breeding of non-1B/1R K-type CMS line with male sterile gene from T. macha. SSR analysis was performed to select molecular markers linked with fertility gene of Tm3314. The main results were as followed:1. Compared with 1B/1R K-type CMS line KD₂3314A, the non-1B/1R K-type CMS lineKTm3314A have no haploid produced, and have better fertility-restoring ability, these properties will be helpful to breed high yield hybrid wheat combinations.2. The male fertility comparison between the male sterile wheat lines and their regenerated tillers were conducted with 1B/1R K-type CMS line KD23314A and the non-lB/lR K-type CMS line KTm3314A. The results suggested that: KD23314A was a stable non-sensitive male sterile wheat line. KTm3314A was a thermo-sensitive male sterile wheat line. This characteristic of its fertility alteration can be inherited stably. KTm3314A could be utilized to establish two-line hybrid wheat production system.3. Tm3314, which has T. timopheewi's cytoplasm, and has the T-type restorer gene of T.machd's chromosome fragment, as male parent, was crossed with monosomic and nullisomic system of Abbondanza wheat. Their Fi monosomic individuals as male parent, crossed with T-type male sterile line TD23314A. The fertility segregation ratio of different testcross progeny were analyzed by chi-square test. The results showed that the major T-type restorer gene was located on chromosome IB, three weak restorer gene or modifier gene located on chromosome 5A> 2B and 4B, and an inhibitor gene located on chromosome ID.4. Tsp3314 as female parent, which has T-type restorer gene from T.spelta, was emasculated and pollinated with Tm3314 as male parent. The Fi individuals were self-pollinated and F2 progeny were obtained. There was no male sterile individual observed in the populations of 386 F2 individuals. The results suggested that the major T-type restorer genes of Tm3314 and Tsp3314 likely are allelic or closely linked. The major T-type restorer gene of T. spelt a was located on the short arm of chromosome IB. Therefore, the major T-type restorer gene of Tm3314 was deduced on the short arm of chromosome IB.5. By applying two different experiments, F2 segregation population and BCj segregation population, the linkage relationship between the major T-type restorer gene and major K-type sterile gene of Tm3314 was analyzed. Experiment of F2 segregation population showed that the two genes did have linkage relationship;the major T-type restorer gene of Tm3314 could be used as the genetic marker of its major K-type male sterile gene. Experiment of BC| segregation population showed that the crossing-over value between the major T-type restorer gene and the major K-type sterile gene was 16.38±2.19%.6. F2 population of T504A/Tm3314 was used in this study to search the molecular marker linked with the fertility genes in T.macha. Fertile bulk and sterile bulk were constructed by BSA method. Two parents and two bulks were analyzed with SSR primers. Codominant SSR primers Xbarc8 and Xgwml8 were found to be polymorphic between the two parents and the two bulks. The two SSR markers were used to detect F2 individuals.Based on the fertility of the F2 individuals under the background of T-type and K-type cytoplasm,using MAPMAKER 3.0b, the genetic distance between Xbarc8, Xgwml8 and the major T-type restorer gene were calculated as 5.5 and 8.1cM, respectively. The genetic distance between Xbarc8, Xgwml8 and the major K-type male sterile gene were calculated as 22.2 and 19.6cM, respectively. Those two SSR markers were located between the major T-type restorer gene and the major K-type sterile gene.