[Pedigree and development of wheat varieties in Sichuan Province].

Variety pedigree contains a lot of information, including parental origin, breeding methods, genetic relationship, and so on. Studying them could reveal the evolution characteristics and rules of breeding and ultimately guide practice. The pedigrees of 326 wheat varieties from 1936 to 2017 in the history of the Sichuan Province was collected and analyzed in terms of breeding methods, parental composition, changes of high frequency parents and backbone parents, genetic contribution, distribution of translocation lines and synthetic germplasms. Over the past 80 years since 1930s, breeders have selected 387 direct parents from a large number of materials, made 256 combinations by means of cross breeding, and have released 314 varieties from them, which contributed directly to wheat breeding and production in Sichuan. Wheat breeding experienced a process from utilizing landraces, introducing foreign germplasm to creating breeding materials independently; high-frequency parents and backbone parents used for breeding gradually changed in different stage of the breeding history. Synthetic germplasms contributed greatly to wheat breeding in recent years. The consistency of breeding objectives will inevitably lead to the loss of genetic diversity and the fragility of genetic basis. In the future, the protection and utilization of genetic resources should be strengthened. In this review, the development of wheat breeding in Sichuan was summarized through pedigree analysis, in order to provide a reference for future research.

[Identification of the 1RS-7DS.7DL wheat-rye small segment translocation lines].

Rye (Secale cereale L., RR) is a valuable genetic resource for the improvement of common wheat (Triticum aestivum L., AABBDD). Transferring alien rye genes into wheat by distant hybridization and automatic chromosome doubling is an important and efficient method to boost agronomic traits, disease resistance and widening the gene pool in wheat. In this study, an octoploid triticale CD-13 (AABBDDRR) was obtained via automatic chromosome doubling by crossing landrace Penganbaimaizi (T. aestivum L., AABBDD) and rye "Qinling rye" (S. cereale cv. Qinling, RR). GISH and FISH analyses indicated that CD-13 contained a 1RS-7DS.7DL wheat-rye small segment translocation chromosome. In order to transfer the 1RS-7DS small segment translocation into hexaploid wheat, 58 lines of the F5 inbred population from the cross CD-13 x Chuanmai 42 were screened for rye chromosome segments by GISH and FISH analyses. The results showed that 13 lines contained the 1RS-7DS.7DL small segment translocation chromosome by reciprocal translocation between 1RS and 7DS. These translocation lines carrying 1RS small rye alien segment were tested for the translocation breakpoints and the presence of a storage protein locus Sec-1. The Sec-1 locus was absent in the line 811, a stable 1RS-7DS.7DL small segment translocation line. The translocation breakpoint of 1RS-7DS.7DL of this line was located in the interval of IB267-IAG95 around the telomere of 1RS chromosome. Thousand-kernel weight of the line 811 was much higher than the parent CD-13, but not significantly different from Chuanmai 42. This indicated that 1RS-7DS.7DL small segment translocation had no negative effect on thousand-kernel weight in the genetic background of Chuanmai 42. The line with 1RS-7DS.7DL translocation chromosomes can be used as a new genetic material for further studies of valuable genes and their genetic effect on 1RS small segment.