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Article
A New Greenhouse Method to Assay Soybean Resistance to Brown Stem Rot
Plant Disease
  • G. A. Tabor, Iowa State University
  • S. R. Cianzio, Iowa State University
  • G. L. Tylka, Iowa State University
  • R. Roorda, Iowa State University
  • C. R. Bronson, Iowa State University
Document Type
Article
Publication Version
Published Version
Publication Date
9-1-2006
DOI
10.1094/PD-90-1186
Abstract
Greenhouse, growth chamber, and field experiments were conducted to develop a method to assess resistance of soybeans to Cadophora gregata (Phialophora gregata), causal agent of brown stem rot (BSR). In the new method, C. gregata is introduced at the base of the stems of 2-week-old soybeans, and the presence of the fungus is assessed in the tips of the stems 5 weeks later. To test the effectiveness of the method, two populations of soybeans and 10 checks were inoculated at the stem base and then assayed for fungal colonization of the stem tips, percentage of symptomatic leaflets, and percent internal stem length discolored. The lines also were planted in naturally infested fields to assess for percent internal stem length discolored, and were tested for the presence/absence of a BSR-resistant molecular marker. Greenhouse, field, and molecular marker data were compared. Linear regression analysis suggested that percentage of plants with colonized stem tips explained 41 to 64% of the variability (P < 0.0001) in percent stem length discolored in the field and 58 to 85% of the variability (P < 0.0001) in molecular marker data for BSR resistance. Percent stem length discolored assessed in the greenhouse had the lowest correlation with percent stem length discolored in the field and with the molecular marker. Of three incubation temperatures tested, 22°C was the most conducive for distinguishing resistant/susceptible soybeans using the colonization method.
Comments

This article is published as Tabor, G. M., S. R. Cianzio, G. L. Tylka, R. Roorda, and C. R. Bronson. "A new greenhouse method to assay soybean resistance to brown stem rot." Plant disease 90, no. 9 (2006): 1186-1194, doi; 10.1094/PD-90-1186. Posted with permission.

Copyright Owner
The American Phytopathological Society
Language
en
File Format
application/pdf
Citation Information
G. A. Tabor, S. R. Cianzio, G. L. Tylka, R. Roorda, et al.. "A New Greenhouse Method to Assay Soybean Resistance to Brown Stem Rot" Plant Disease Vol. 90 Iss. 9 (2006) p. 1186 - 1194
Available at: http://works.bepress.com/gregory-tylka/171/