|Bosak, Karen - WSU-IAREC, PROSSER, WA|
Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 6, 2004
Publication Date: November 1, 2004
Citation: Miklas, P.N., Bosak, K. 2004. Marker-assisted backcrossing of qtl for resistance to sclerotinia white mold in pinto bean. American Society of Agronomy Abstracts. Madison, WI. No. 3497. Technical Abstract: Resistance to white mold in dry bean is quantitatively inherited with low to moderate heritability. Evaluation of resistance is further complicated by expression of both avoidance traits and physiological mechanisms. The identification of quantitative trait loci (QTL) with major-effect on resistance provides an opportunity to use marker-assisted breeding to combine resistance sources and expedite development of pinto bean cultivars with enhanced levels of white mold resistance. Two such QTL, with expression in both the greenhouse straw test and field, derive from different sources: G122, a large-seeded landrace from India, and NY6020-4, a snap bean breeding line from Cornell University. The QTL from G122 and NY6020-4 reside on different linkage groups, B7 and B8, respectively. Tightly linked DNA markers were used to introgress the QTL into susceptible pinto bean cultivars using up to three marker-assisted backcrosses. The BC3F4:6 lines were tested for the markers and disease reaction to white mold. The markers explained 35% of the variation in disease reaction indicating they were effective for marker-assisted selection of disease resistance in pinto bean. Advanced pinto bean lines from these crosses with resistance to white mold were obtained and will be tested in white mold trials across to the country to determine their full potential for combating this devastating disease.