Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 30, 2005
Publication Date: January 18, 2006
Citation: Miklas, P.N. 2006. QTL for white mold resistance in I9365-31 dry bean derived from P. vulgaris x P. coccineus. National Sclerotinia Initiative Annual Meeting, January 18-20, 2006, Minneapolis, MN, p. 7. 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 is a black bean line that possesses resistance to white mold putatively derived from scarlet-runner bean. The objective of this research was to characterize resistance of I9365-31 to white mold in a mapping population tested across multiple field (two) and greenhouse environments (five). A recombinant inbred population consisting of 109 F5:8 lines was developed from the cross Raven/I9365-31. ‘Raven’ is a commercial black bean susceptible to white mold. Separate R and S bulks for greenhouse and field reactions to white mold were used in bulked-segregant analyses to identify markers associated with resistance in the field and greenhouse. There were four independent quantitative trait loci (QTL) identified that conditioned resistance to white mold in the field. All four QTL were expressed (explaining from 9% to 24% of the phenotypic variation for disease score) across multiple environments (two years). The QTL were associated with disease avoidance traits, canopy porosity (7% to 24%) and canopy height (7% to 11%). Two major independent QTL conditioning resistance in the greenhouse were stably expressed across five separate straw tests. Phenotypic variation explained by the QTL ranged from 22% to 37%. Both QTL had minor expression in the field (5% to 9%). To determine utility for indirect selection, the major QTL detected by the straw test will be validated in different genetic backgrounds using marker-assisted backcrossing.