2014
Mapping genes referring resistance to white mold
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Contributor/Checkoff:
North Central Soybean Research Program
Category:
Sustainable Production
Keywords:
GeneticsGenomics
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Brian Diers, University of Illinois at Urbana-Champaign
Co-Principal Investigators:
Craig Grau, University of Wisconsin
Project Code:
Contributing Organization (Checkoff):
North Central Soybean Research Program
(n/a)
Institution Funded:
University of Illinois-Carbondale
(n/a)
Brief Project Summary:

In this project, we are mapping genes that confer resistance to white mold. The availability of genetic markers that can be used to select for these resistance genes has the potential for improving progress in breeding for white mold resistance.

White mold can cause significant yield losses to growers when environmental conditions are favorable to disease development. Although genetic resistance to white mold has been reported, the sporadic nature of the disease has made the development of resistant varieties difficult. This is because varieties are often developed and marketed before there is an opportunity to test them for resistance. Knowing the locations of these resistance genes...

Unique Keywords:
#breeding & genetics, #sclerotinia sclerotiorum, #sclerotinia white mold, #soybean genetic mapping, #soybean genetic markers
Information And Results
Final Project Results

This research was focused on mapping genes that control resistance to white mold using the experimental line W04-1002 as a resistance source because it represents a unique and stable source of white mold resistance. W04-1002 was developed from PI 567157A by selecting plants that were resistant from the original PI line. W04-1002 was crossed with four parents that were rated as susceptible to white mold in greenhouse and field trials and expressed resistance to brown stem rot and soybean cyst nematode. Lines developed from these crosses were tested in the field and selected for limited lodging, maturity date (MG0 to MGII), and absence of disease symptoms after the lines were tested for reactions to white mold. These reactions were determined by inoculating plants in a greenhouse and rating them on a scale of 0 (no stem lesion), 1 (small lesion), 2 (lesion but no wilt), 3 (wilt), and 4 (dead plant). Lines with a mean severity score of 0 to 1 were characterized as resistant.

There was a continuous distribution of resistance levels for lines in the populations, which shows that the inheritance is likely controlled by many genes with small effects and not controlled by major genes. All lines in the four populations were tested with genetic markers located in genetic regions that were indicated by preliminary work as possible sites of genes for white mold resistance. Genes controlling quantitative traits like white mold resistance are called quantitative trait loci, or QTL. The marker analysis revealed the location of one QTL on chromosome 15 in the 4x1 population, one QTL on chromosome 19 in the 5x1 population, QTLs on chromosomes 17 and 18 in the 8x1 population, and QTLs on chromosomes 16 and 19 in the 9x1 population. For many of these chromosomes, multiple significant markers were identified in each population, but these multiple markers are likely linked to the same resistance QTL on each chromosome. The QTL identified from the resistant parent in these populations can be used by breeders to develop white mold resistant varieties by directly selecting markers associated with the QTL in breeding programs.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.