[Molecular cytogenetic identification of a new 1RS/1BL translocation line with secalin absence]

The wheat-rye translocation 1RS/1BL has spread to wheat breeding programs and commercial wheat cultivars throughout the world. But the 1RS arm in the translocation carries locus Sec-1, which encodes rye storage proteins (secalins) and affects bread- making quality. In this study an attempt was made to remedy the quality defect of the 1RS translocation in wheat by developing new 1RS/1BL lines. The chromosomal constitution of 200 advanced lines from 1R monosomic addition lines between the wheat cultivar Mianyang11 (MY11) and different rye lines R3, R12, and Baili-rye was studied by the improved C-banding and A-PAGE method. The result showed that 45 lines were identified as 1RS/1BL translocation lines congruously by the two methods. But a line (843-1-1), originated from an 1R addition line of wheat cultivar MY11 and rye line R12, was identified as 1RS/1BL translocation line by C-banding and genomic in situ hybridization(GISH), but the secalin block from chromosome arm 1RS of rye was absent in the A-PAGE pattern of its seed proteins. It is sure that the wheat line 843-1-1 carries a pairs of 1RS/1BL chromosomes with expression absence of the Sec-1 site. It is a rarely material for further study on the effect of 1RS/1BL translocation on wheat quality. The results indicated that wide genetic variability may exist in rye population, which can be exploited for wheat breeding.