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United States Department of Agriculture

Agricultural Research Service

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Research Project: Enhancing Soybean for Resistance to Sclerotinia Stem Rot

Location: Sunflower Research

Project Number: 3060-21220-028-26
Project Type: Specific Cooperative Agreement

Start Date: Jun 01, 2014
End Date: Sep 30, 2015

Objective:
The long-term goal of this project is to develop soybean varieties or germplasm that have a high level of resistance to Sclerotinia stem rot. The short-term supporting objectives are: 1. evaluate advanced breeding lines for resistance to Sclerotinia stem rot and for agronomic performance, and release the best lines as germplasm or varieties; 2. identify SNP markers that are closely linked to QTLs for resistance to Sclerotinia stem rot; 3. incorporate new sources of resistance to Sclerotinia stem rot into elite soybean germplasm; 4. develop mapping populations to identify QTLs for resistance to Sclerotinia stem rot in the new resistance sources.

Approach:
For objective 1, over 70 advanced breeding lines derived from multiple sources of resistance to Sclerotinia will be evaluated in 2014 at seven locations in Michigan for yield and agronomic traits. The lines will also be evaluated for resistance to Sclerotinia stem rot in a Sclerotinia disease nursery and in the greenhouse with the drop-mycelium method developed by us. About 15% of the lines will be selected based on their resistance to Sclerotinia stem rot, yield, and other agronomic traits. The selected lines will be re-evaluated in our disease nursery for resistance to Sclerotinia stem rot and yield under disease pressure. Five to 10 lines will be selected and tested in the Uniform Soybean Tests – Northern Region (19 locations in 10 northern US states and 1 Canadian province), for yield and other agronomic traits. The best lines will be released to the public. For objective 2, the advanced breeding lines evaluated in objective 1 will be genotyped with over 52,000 SNP markers on the Illumina iSelct BeadChips developed for soybean by Dr. Perry Cregan’s lab. The SNP marker data and the disease resistance data obtained for objective 1 will be analyzed together to identify SNP markers that are closely linked to QTLs for resistance to Sclerotinia stem rot. For objective 3, three new sources of resistance to Sclerotinia stem rot, PI 416805, PI 361059B, and FC 030233, will be crossed to elite soybean germplasm with high yielding and with other desirable traits. The progenies from the crosses will be inbred to F4 generation by planting a single seed from each plant of the earlier generation, starting from F2 generation (single seed descend). Each F4 plants will be individually harvested as a single F4 derived line. The F4 derived lines will be evaluated for resistance to Sclerotinia stem rot, yield, and other desirable traits. Lines with resistance to Sclerotinia stem rot from the new resistances and with other desired traits such as yield and resistance to other diseases will be selected for further evaluations. For objective 4, the three new resistance sources, PI 416805, PI 361059B, and FC 030233, will each be crossed with two high yielding lines to develop two mapping populations for each new resistance source. One mapping population will be needed as the primary mapping population and the second population will be needed as the confirmation population. Each population will have at least 200 F4 derived lines. F2 progenies from each cross will be advanced to F4 generation by the single seed descend method. F4 plants will be individually threshed to create F4 derived lines.

Last Modified: 10/30/2014
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