Submitted to: ARS Sclerotinia Initiative Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: December 12, 2006
Publication Date: January 17, 2007
Citation: Miklas, P.N. 2007. White mold resistance in dry bean derived from P. vulgaris x P. coccineus. ARS Sclerotinia Initiative Annual Meeting, Minneapolis, MN, Jan. 17-19, 2007. Technical Abstract: Scarlet-runner bean (Phaseolus coccineus L.), a representative species of the secondary gene pool of common bean, is a potential source of white mold resistance for improving dry bean. I9365-31, I9365-25, and VA19 are dry bean lines that possess resistance to white mold putatively derived from scarlet-runner bean. The objective of this research was to characterize resistance of these lines to white mold in mapping populations tested across multiple field and greenhouse environments. Recombinant inbred populations consisting of F5-derived lines were developed from the crosses Raven/I9365-31, Montrose/I9365-25, and Benton/VA19. Raven and Montrose are commercial black and pinto bean, respectively, susceptible to white mold. Benton is a susceptible snap bean. Separate R and S bulks for field and greenhouse reactions to white mold were used in bulked-segregant analyses to identify markers associated with resistance in the Raven/I9365-31 population. There were four independent quantitative trait loci (QTL) expressed across field environments, explaining from 9% to 24% of the phenotypic variation for disease score. Two major independent QTL conditioning resistance (22% to 37%) in the greenhouse were stably expressed across five separate straw tests. Integrating the QTL from this population on the core map has been difficult and is still in progress. Disease reaction for the Benton/VA19 population has been obtained from multiple field and greenhouse environments. Preliminary assay of the Benton and VA19 parents with SRAP markers indicate adequate polymorphism for mapping traits in the corresponding RIL population. The Montrose/I9365-25 population has been tested for disease reaction in only one field and one greenhouse environment, thus far. The narrow range for reaction to white mold observed among RILs suggests this population may not be suitable for mapping QTL conditioning resistance.