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United States Department of Agriculture

Agricultural Research Service

Research Project: REDUCING SOYBEAN YIELD LOSSES THROUGH GENETIC IMPROVEMENT Title: Identification of a new soybean rust resistance gene in PI 567102B

Authors
item Li, Shuxian
item Smith, James
item Ray, Jeffery
item Frederick, Reid

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 5, 2012
Publication Date: May 16, 2012
Citation: Li, S., Smith, J.R., Ray, J.D., Frederick, R.D. 2012. Identification of a new soybean rust resistance gene in PI 567102B. Theoretical and Applied Genetics. 125:133-142.

Interpretive Summary: Soybean rust (SBR) is one of the most economically important diseases of soybean Durable resistance to SBR is the most effective long-term strategy to control SBR. The objective of this study was to investigate the genetics of resistance to SBR in a soybean line PI 567102B that was previously identified as resistant in Paraguay and seven states in the US (Alabama, Florida, Georgia, Louisiana, Mississippi, South Carolina, and Texas). We found that the SBR resistance in PI 567102B is conditioned by a previously unreported gene. We propose that this new gene be designated Rpp6. Incorporating Rpp6 into improved soybean cultivars may have wide benefits as it has been shown to have resistance to SBR in Paraguay and the U.S.

Technical Abstract: Soybean rust (SBR) caused by Phakopsora pachyrhizi Syd. & P. Syd. is one of the most economically important diseases of soybean [Glycine max (L.) Merr.]. Durable resistance to P. pachyrhizi is one of the most effective long-term strategy to control SBR. The objective of this study was to investigate the genetics of resistance to P. pachyrhizi in soybean accession PI 567102B. This accession was previously identified as resistant in Paraguay and to P. pachyrhizi isolates from seven states in the US (Alabama, Florida, Georgia, Louisiana, Mississippi, South Carolina, and Texas). Analysis of two independent populations, one where F2 phenotypes were inferred from F2-derived F3 (F2:3) lines and the other where F2 plants were phenotyped directly, showed that the resistance in PI 567102B is controlled by a single dominant gene. Two different isolates (MS06-1 and LA04-1) at different locations (Stoneville, MS and Ft. Detrick, MD) were used to independently assay the two populations. Linkage analysis of both populations indicated that the resistance locus was located on linkage group G, but at a different location than that of either Rpp1 or Rpp4, which were previously mapped to this linkage group. Thus we conclude that the SBR resistance in PI 567102B is conditioned by a previously unreported gene. We propose that this new gene be designated Rpp6. Incorporating Rpp6 into improved soybean cultivars may have wide benefits as it has been shown to have resistance to P. pachyrhizi isolates from Paraguay and the U.S.

Last Modified: 12/19/2014
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