Tuesday, November 14, 2006 - 9:15 AM

Development of Common Bean Cultivars with Multiple Disease Resistances Using Marker Assisted Selection.

Shuyu Liu1, Kangfu Yu1, Soon Park1, Robert L. Conner2, Parthiba Balasubramanian2, H.-Henning Mundel3, and Ferdinand Kiehn2. (1) Agriculture and Agri-Food Canada, 2585 County Rd. 20, Harrow, N9E 3X4, CANADA, (2) Morden Research Station, Unit 100-101 Route 100, Morden, ON R6M 1Y5, Canada, (3) AAFC-Lethbridge Research Center, 5403 - 1st Avenue, Lethbridge, AB T1J 4B1, Canada

Common bean (Phaseolus vulgaris L.) is one major protein resource in human diet. Three major diseases, including common bacterial blight (CBB), anthracnose and bean common mosaic virus (BCMV) decrease both bean seed yield and quality. The most efficient and environmentally sound way to control these diseases is by growing resistant cultivars. As molecular markers linked to all three disease resistance genes are available, this study was designed to breed bean cultivars resistant to all three disease resistances simultaneously using backcrossing and marker-assisted selection. SCAR marker UBC420 is linked to a major CBB resistance QTL, while SW13 is linked to the I gene conditioning the BCMV resistance and SBB14 is linked to the Co-42 gene with the broadest resistance to several anthracnose races. Among all four major market classes, including navy, black, pinto and red kidney bean, 2 to 4 adapted cultivars from each region were used as recurrent parents. Starting from F1 and the subsequent BCnF1, all hybrid plants were screened for the three markers. Only those plants with at least two markers were used as male parents for next backcrossing. Starting from BC4F1 generation, hybrid plants were also inoculated for phenotype confirmation. We obtained BC3F1 to BC5F1 plants carrying at least two disease resistances for all four market classes. The BCnF2 plants were evaluated in the field to test both disease resistances and other agronomic traits. The UBC420 marker is tightly linked to the V gene which produces undesirable seed coat color in pinto and cranberry beans. With the breeding effort, pure lines with UBC420 but lacking OD12S marker which is linked to the V gene, were identified. Progress of backcrossing coupled with marker-assisted selection and some concerns related to this technique will be presented.