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ARS Home » Midwest Area » East Lansing, Michigan » Sugarbeet and Bean Research » Research » Publications at this Location » Publication #316250
Title: Screening of a dry bean Andean diversity panel for potential sources of resistance to Rhizoctonia crown and root rot

Author
item MINIER, D - Michigan State University
item Hanson, Linda

Submitted to: Annual Beet Sugar Development Foundation Research Report
Publication Type: Research Notes
Publication Acceptance Date: 4/15/2015
Publication Date: 6/1/2015
Citation: Minier, D., Hanson, L.E. 2015. Screening of a dry bean Andean diversity panel for potential sources of resistance to Rhizoctonia crown and root rot. [CD-ROM] 2014 Annual Beet Sugar Development Foundation Research Report. Denver, Colorado: Beet Sugar Development Foundation.

Interpretive Summary:

Technical Abstract: Rhizoctonia crown and root rot (RCRR), caused by Rhizoctonia solani, is a major problem in most sugar beet production areas and can cause substantial losses in both yield and quality. Over the last decade, it has become the most prevalent root disease of sugar beet in Michigan and several other regions. RCRR also interacts with other pathogens to cause considerably more damage than either pathogen causes alone. One method to manage the disease is rotation with non-host crops to reduce inoculum build-up in the soil. The majority of crops grown in rotation with sugar beet in Michigan are susceptible to this pathogen however. The goal of this project is to identify potential sources of Rhizoctonia root rot resistance in dry beans using materials from an Andean ancestral gene pool (ADP) that could be introduced into locally adapted varieties to provide expanded options for crop rotation in the management of sugar beet RCRR. Initial screening was with five germplasm that had shown potential for reduced disease severity in a preliminary seedling screen of 18 bean germplasm. Two of these germplasm showed a significantly lower mean disease index (DI) than the control variety Red Hawk when inoculated with R. solani AG2-2 as adults. However, disease ratings in seedlings were not significantly different from the control. DI to AG4 in seedlings was significantly lower than the control for one of these germplasm but not the other. To develop a method to prioritize from the over 500 ADP available, a correlation matrix between DI and sixteen phenotypic traits followed by regression analysis and a neighbor joining tree that had been developed using single nucleotide polymorphisms were used to compare 24 germplasm tested for DI. The correlation matrix showed a significant negative correlation between mean disease index and seed weight (p < 0.05) and seed weight showed a significant linear relationship to mean disease index (p = 0.006, R2 = 0.297) by regression analysis. Thus seed weight will be considered in selecting germplasm for screening. In the neighbor joining tree, four of the lower DI germplasm were located in a single clade and three group in a cluster of about 16 germplasm. This cluster will be tested for good candidates for further screening.