ARS | Publication request: POTENTIAL MARKER-ASSISTED SELECTION FOR RESISTANCE TO WHITE MOLD IN PINTO AND GREAT NORTHERN BEAN

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 30, 2005
Publication Date: January 18, 2006
Citation: Miklas, P.N. 2006. Potential marker-assisted selection for resistance to white mold in pinto and great northern bean. National Sclerotinia Initiative Annual Meeting, January 18-20, 2006, Minneapolis, MN, p. 5.

Technical Abstract: The identification of quantitative trait loci (QTL) with major-effect on resistance provides an opportunity to use marker-assisted breeding to expedite development of cultivars with enhanced levels of white mold resistance. Two such QTL from G 122 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 ‘Winchester’ (Pop I and II, -B7 QTL) and ‘Maverick’ (Pop III and IV, -B8 QTL), and great northern cultivar ‘Matterhorn’ (Pop V, -B8 QTL), using up to three marker-assisted backcrosses. The B7 QTL had major effect in the greenhouse straw test explaining 42% and 64% of the variation in reaction, respectively, for Pop I and II. The B7 QTL exhibited less effect in the field, 17% and 12% for Pop I and II, respectively, in part, because of poor disease pressure. Similarly, the B8 QTL had major influence in the straw test explaining 47, 35, and 26% of the variation in disease reaction for Pop III, IV, and V, respectively. The B8 QTL was also expressed in the field as measured for Pop IV (17%) and Pop V (27%). Although the QTL explained a major portion of the phenotypic variation for disease reaction in the backcross populations they had only minor effect on the level of resistance conferred. Further research and germplasm development will be needed to recover pinto bean and great northern bean possessing both B7 and B8 QTL for white mold resistance with acceptable maturity, seed quality, and yield.