Soybean cyst nematode (SCN) is a persistent threat to growers throughout Minnesota. Fields infested with SCN are more susceptible to other disease, pest, and environmental stresses. Moreover, many parts of Minnesota have seen a breakdown in varietal resistance, with the appearance of new SCN races capable of overcoming the widely grown 88788-source of resistance. If fact, three of our testing sites (including Crookston) had SCN populations determined to be of HG Type 2 which are virulent on PI 88788.
Developing new germplasm with alternative forms of resistance to combat resistance breakdown for long-term success is an important function of the public sector breeding efforts. With this in mind, our overall objective is to advance the development of SCN-resistant soybean varieties as well as provide accurate and unbiased sources of information on the resistance of commercial soybean varieties. Our specific aims are to: 1) Enhance the efficiency and efficacy of breeding for SCN resistance through the deployment of DNA markers linked to major genes conferring SCN resistance; 2) Advance new sources of SCN resistance and expand the use of these new sources for crossing in the breeding program; 3) Conduct SCN bioassays on commercial varieties entering the 2023 UMN Variety Trials, as well as all non-88788 commercial SCN varieties available to Minnesota growers.

Goals 1. Continue to efficiently produce new SCN-resistant germplasm and varieties and thus expand availability of SCN resistance across all maturity groups grown in Minnesota.
Objective 1. Deploy DNA markers linked to genes conferring SCN resistance to enhance the efficiency and efficacy of breeding for SCN resistance.

Goals 2. Create elite soybean germplasm with non-88788 sources of SCN resistance so that future soybean growers have more tools in their toolbox to compete with this evolving major pest of soybean.
Objective 2. Advance new sources (non-88788) of SCN resistance and expand the use of these new sources as parents for crossing in the breeding program

Goals 3. Provide an unbiased source of information to growers on the level of SCN resistance in 88788-type commercially available varieties as well as those that have non-88788 sources of resistance.
Objective 3. Conduct SCN bioassays on commercial varieties entering the 2024 UMN Variety Trials using race 3, and conduct bioassays on commercially available non-88788 SCN varieties using races 3 and 14.

1) Public and licensed SCN-resistant varieties, particularly ones carrying the non-88788 source of resistance such as Peking, 567516C, and 90763; 2) An unbiased source of information on the actual SCN resistance of currently available 88788-type resistant varieties to race 3 (HG Type 0); and 3) An unbiased source of information on the resistance of advertised non-88788 resistant varieties to SCN race 1 (HG Type 2.5.7).

The proposed research addresses three areas targeted by the Production Action Team’s mission statement: (1) Plant breeding and genetics; (2) Molecular breeding and functional genomics; (3) Soybean cyst nematode (SCN). The work we propose aims to increase soybean yield and profit potential by providing growers with a broader range of variety options with stable or enhanced yield even in fields infested by SCN. To increase the utility of our work, we are introducing novel sources of resistance into Minnesota soybeans, combining SCN resistance with other marketable traits, and making our germplasm available to the broader community to catalyze additional variety development for the future benefit of Minnesota growers. We will also provide an unbiased source of information on the SCN resistance of commercially available varieties. This is particularly important for the non-88788 varieties, which have not been verified in this way before.