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Molecular and cytogenetic characterization of a small alien-segment translocation line carrying the softness genes of Haynaldia villosa
- Zhang, Ruiqi, Wang, Xiue, Chen, Peidu
- Genome 2012 v.55 no.9 pp. 639-646
- Dasypyrum villosum, Triticum, backcrossing, chromosome translocation, chromosomes, females, genes, genetic markers, germ cells, grain quality, hardness, homozygosity, texture, wheat
- The wheat–alien small segment translocation (SAST) lines carrying the beneficial genes from wild species are useful genetic stocks for wheat improvement. In this study, to introduce the grain hardness-related genes of Haynaldia villosa (L.) Schur. into common wheat (Triticum aesitivum L.), the mature female gametes of whole-arm wheat – H. villosa translocation line T5VS·5DL was irradiated by ⁶⁰CO-γ ray to develop SAST lines involving 5VS. Among the BC₂F₂ population, six homozygous SAST lines with different fragment sizes of 5VS were identified by GISH, and the exact fragment sizes were further defined using four 5VS-specific markers and four Ha gene-based markers. The results showed that five lines (NAU5VS-1 to NAU5VS-5) carried the softness gene Dina/Dinb of H. villosa, and that NAU5VS-5 had the smallest alien translocation segment, identified to be a 5VS-6AS·6AL terminal translocation. The translocation chromosome 5VS-6AS·6AL was proved to be stably inherited to the successive generations. In the BC₃F₂ generation, the individuals having the homozygous 5VS-6AS·6AL translocation chromosomes all showed soft grain texture, with an approximately 50% reduction in the SKCS hardness index compared with that of their backcrossing parent. Both the 5VS-6AS·6AL translocation line and the molecular markers developed in this study will be valuable in wheat breeding for soft grain quality improvement.