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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVEMENT OF HARD RED SPRING AND DURUM WHEAT FOR DISEASE RESISTANCE AND QUALITY USING GENETICS AND GENOMICS

Location: Cereal Crops Research

Title: Synthetic hexaploids: Harnessing species of the primary gene pool for wheat improvement

Authors
item Ogbonnaya, Francis -
item Abdalla, Osman -
item Kazi-Mujeeb, Abdul -
item Kazi, Alvina -
item Xu, Steven
item Gosman, Nick -
item Lagudah, Evans -
item Bonnett, David -
item Sorrells, Mark -

Submitted to: Plant Breeding Reviews
Publication Type: Review Article
Publication Acceptance Date: January 1, 2012
Publication Date: June 26, 2013
Citation: Ogbonnaya, F.C., Abdalla, O., Kazi-Mujeeb, A., Kazi, A.G., Xu, S.S., Gosman, N., Lagudah, E.S., Bonnett, D., Sorrells, M.E. 2013. Synthetic hexaploids: Harnessing species of the primary gene pool for wheat improvement. Plant Breeding Reviews. 37:35-122.

Interpretive Summary: Incorporation of desirable genes into elite wheat cultivars has long been recognized as a means of improving wheat productivity and securing the global wheat supply. Synthetic hexaploid wheat (SHW), created from the hybrids between tetraploid wheat and goatgrass species Aegilops tauschii, is a useful resource of new genes for bread wheat improvement. These include many productivity traits such as ability to withstand hostile environment (drought, heat, salinity, and waterlogging stress), plant disease (rusts, leaf blotch, barley yellow dwarf virus, crown rot, tan spot, spot blotch, powdery mildew, and scab), insect resistance (nematodes) and novel quality traits. In the past seven decades, numerous SHW lines have been produced globally. In this review, we examine the varied aspects for utilization of SHWs, and their derived wheat lines for wheat improvement. We discuss the traits and genes identified, mapped and transferred to bread wheat. By identifying gaps in the existing SHW germplasm, we suggest that future production of new SHW should extend to exploiting under-exploited tetraploid wheat such as Persian wheat and emmer wheat. We suggest that the recent advances in molecular technologies will provide researchers with opportunities for detailed analysis of traits and the deployment of efficient strategies to use unique genes derived from SHW for bread wheat improvement. Thus, the contribution of SHW and the derived wheat germplasm to world-wide wheat cropping systems is likely to grow in significance.

Technical Abstract: Incorporation of genetic diversity into elite wheat cultivars has long been recognized as a means of improving wheat productivity and securing the global wheat supply. Synthetic hexaploid wheat (SHW) recreated from its two progenitor species, the tetraploid, Triticum turgidum and its diploid wild relative, Aegilops tauschii, are a useful resource of new genes for common wheat improvement. These include many productivity traits such as abiotic (drought, heat, salinity/sodicity and waterlogging) and biotic (rusts, septoria, barley yellow dwarf virus, crown rot, tan spot, spot blotch, nematodes, powdery mildew, and Fusarium head blight) stress resistance/tolerances as well as novel quality traits. In the past seven decades, numerous SHW lines have been produced globally by various institutions. This review examines the aspects in the utilization of SHW and synthetic backcross derived wheat lines (SBLs) for wheat improvement including the traits and genes identified, mapped and transferred to common wheat. By identifying gaps in the existing SHW germplasm, we suggested that future production of new SHW should extend to tetraploids of the A and B genomes, such as T. turgidum ssp. carthlicum, T. turgidum ssp. dicoccum, and T. turgidum ssp. dicoccoides. In this review, we indicated that the recent advances in molecular technologies with whole genome sequencing will provide researchers with detailed analysis of traits and the deployment of more efficient strategies in the use of unique exotic alleles derived from SHW for common wheat improvement. Thus, the contribution of SHW and the derived SBL to wheat cropping systems worldwide is likely to grow in significance.

Last Modified: 10/1/2014
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