Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2006
Publication Date: 3/17/2006
Citation: Oliver, S.S., Xu, S.S., Stack, R.W., Friesen, T.L., Jin, Y., Cai, X. 2006. Molecular cytogenetic characterization of four partial wheat-thinopyrum ponticum amphiploids and their reactions to fusarium head blight, tan spot, and stagonospora nodorum blotch. Theoretical and Applied Genetics. 112:1473-1479. Interpretive Summary: Four wheat-tall wheatgrass (Thinopyrum ponticum) derivatives, including SS5 (PI604926), SS156 (PI604947), SS363 (PI604970), and SS660 (PI604879), were previously developed by W. J. Sando. Their chromosome compositions and potential usefulness for wheat improvement have not been investigated. Genetic characterization of these wheat-tall wheatgrass derivatives, as well as knowledge of their reactions to multiple diseases, can facilitate their utilization in wheat breeding. In this study, we evaluated these wheat-tall wheatgrass derivatives for their resistance to scab, tan spot, and Stagonospora nodorum blotch (SNB) and characterized their chromosome constitutions using molecular and cytological approaches. The results indicated that all four derivatives were resistant to scab and tan spot and two (SS5 and SS156) also were resistant to SNB. Cytological and molecular analysis showed that these four derivatives were partial wheat-tall wheatgrass amphiploids with 56 chromosomes and each of the partial amphiploids carried a similar set of chromosomes from tall wheatgrass. These partial wheat-tall wheatgrass amphiploids represent a potential novel source of resistance to scab, tan spot, and SNB for wheat breeding.
Technical Abstract: Four wheat (Triticum aestivum L.)-Thinopyrum ponticum derivatives, SS5 (PI604926), SS156 (PI604947), SS363 (PI604970), and SS660 (PI604879), were identified as resistant to Fusarium head blight (FHB), a serious fungal disease of wheat. Seedling reactions to tan spot and Stagonospora nodorum blotch (SNB), two important foliar diseases of wheat, suggest that these four derivatives are resistant to tan spot and two (SS5 and SS156) also are resistant to SNB. Fluorescent genomic in situ hybridization (FGISH) patterns of mitotic chromosomes indicated that these four derivatives were partial wheat-Th. ponticum amphiploids, each with a total of 56 chromosomes, though with different amounts of Th. ponticum chromatin. These four amphiploids were hybridized with each other to determine homology between the Th. ponticum genomes in each of the amphiploids. Fluorescent in situ hybridization analysis of chromosome pairing configurations in the F1 hybrids suggests that each amphiploid carries a similar set of Th. ponticum chromosomes. The Th. ponticum amphiploids represent a potential novel source of resistance to FHB, tan spot, and SNB for wheat breeding.