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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetic Improvement of Durum and Spring Wheat for Quality and Resistance to Diseases and Pests

Location: Cereal Crops Research

Title: Molecular cytogenetic characterization and stem rust resistance of five wheat-thinopyrum ponticum partial amphiploids

Authors
item Zheng, Qi -
item Lv, Zhenling -
item Niu, Zhixia -
item Li, Bin -
item Li, Hongwei -
item Xu, Steven
item Han, Fangpu -
item Li, Zhensheng -

Submitted to: Journal of Genetics and Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 9, 2014
Publication Date: N/A

Interpretive Summary: An amphiploid is a hybrid having a diploid (i.e. cells have two homologous copies of each chromosome) set of chromosomes derived from each parental species. Wheat-tall wheatgrass (Thinopyrum ponticum) partial amphiploids created by crossing bread wheat to tall wheatgrass usually contain a complete set of wheat chromosomes and a partial set of wheatgrass chromosomes. They are an important bridging germplasm for transferring useful genes from the grass chromosomes into wheat chromosomes. In this study, we examined chromosome composition of five Xiaoyan-series wheat-tall wheatgrass partial amphiploids (Xiaoyan 68, Xiaoyan 693, Xiaoyan 784, Xiaoyan 7430 and Xiaoyan 7631) using molecular cytogenetic techniques. We also evaluated and characterized these materials for their resistance to nine races of stem rust, including Ug99. The cytogenetic analysis revealed several chromosome changes in these lines. For example, wheat chromosomes 1B or 2B were added in Xiaoyan 68 and Xiaoyan 7430, respectively; whereas wheat chromosome 6B was missing from Xiaoyan 693 and Xiaoyan 7631. Chromosome rearrangements were also detected in these amphiploids, including an interchange involving chromosome 4D. Analysis of the wheatgrass chromosomes in the amphiploids showed that some lines shared the same alien chromosomes. Stem rust evaluation showed that three lines, including Xiaoyan 68, Xiaoyan 784, and Xiaoyan 7430 exhibited excellent resistance to all nine races and they were a valuable source of stem rust resistance.

Technical Abstract: Partial amphiploids created by crossing common wheat (Triticum aestivum L.) and Thinopyrum ponticum (Podp.), Barkworth & D. R. Dewey may be resistant to major wheat diseases and are an important intermediate material in wheat breeding. In this study, we examined chromosome composition of five Xiaoyan-series wheat-Th. ponticum partial amphiploids (Xiaoyan 68, Xiaoyan 693, Xiaoyan 784, Xiaoyan 7430 and Xiaoyan 7631) using GISH, multicolor-GISH, and multicolor-FISH. We also evaluated and characterized these materials for their resistance to nine races of stem rust, including TTKSK (commonly known as Ug99). The cytogenetic results revealed several chromosome changes in these lines. For example, wheat chromosomes 1B or 2B were added in Xiaoyan 68 and Xiaoyan 7430, respectively; whereas wheat chromosome 6B was missing from Xiaoyan 693 and Xiaoyan 7631. Chromosome rearrangements were also detected in these amphiploids, including an interspecific translocation involving chromosome 4D and some intergenomic translocations among wheat genomes. Analysis of the Th. ponticum chromosomes in the amphiploids showed that some lines shared the same alien chromosomes. Stem rust evaluation showed that three lines, including Xiaoyan 68, Xiaoyan 784, and Xiaoyan 7430 exhibited excellent resistance to all nine races and they were a valuable source of stem rust resistance.

Last Modified: 10/1/2014
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