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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Research Project #442184

Research Project: NSI: Developing Soybean Varieties with Resistance to Sclerotinia Stem Rot

Location: Sunflower and Plant Biology Research

Project Number: 3060-21220-034-024-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Jul 1, 2022
End Date: Dec 31, 2024

Objective:
1. To continue the breeding pipeline for enhancing resistance to soybean white mold; 2. To identify the resistance quantitative trait loci and develop markers using nested association mapping populations; and 3. To continue the evaluation of advanced breeding lines for enhanced resistance and release the best lines as varieties.

Approach:
For Objective 1, we will make at least 10 new cross combinations focusing on yield, protein, and the white mold disease package. The new cross combinations will be made between elite lines carrying special traits such as high yield, high protein, and high oleic, and white mold resistance lines, which were identified from previous research. In addition, more than 100 lines from prior year Advanced Yield Trials will be evaluated. For Objective 2, a previously developed nested association mapping (NAM) population will be used to generate a high-density genetic map. Leaf samples of F4 individuals for each line will be bulk harvested and stored in a freezer and DNA samples will be isolated from the leaf samples using standard CTAB method. DNA for each line will be assessed with the SoySNP3K bead chips to genotype the NAM population. High-resolution genetic maps and hapmaps will be generated using JoinMap 4.0 and Tassel software. For Objective 3, over 100 advanced breeding lines (F7 & F8) derived from multiple sources of resistance to white mold will be evaluated for resistance to white mold. An irrigation system will be used to provide the wet condition to promote the disease development during the flowering period. Five to 10 lines will be selected and subsequently 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 or used as new parental lines in future evaluations.