|Miklas, Phillip - Phil|
Submitted to: Proceedings of the International Sclerotinia Workshop
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2005
Publication Date: 6/10/2005
Citation: Lema, M., Teran, H., Otto, K., Schwartz, H.F., Miklas, P.N., Singh, S.P. 2005. Recurrent selection for white mold resistance in dry bean. Proceedings of the 13th International Sclerotinia Workshop, Modesto, CA, June 12-16, 2005. p. 9.
Technical Abstract: White mold is an endemic and one of the most devastating diseases of dry and snap beans in North America. Only low to moderate levels of resistance is available in dry and snap beans. Although high levels of resistance exist in the secondary gene pool, only moderate levels of resistance have been transferred to dry and snap beans. White mold resistance is quantitatively inherited with >10 quantitative trait loci (QTL) distributed across the genome. Breeding methods used thus far, with or without the use of molecular markers, have been grossly inadequate such that improved breeding lines and cultivars, at best, have moderate resistance that may not hold under severe disease pressure. Our objective is to combine the gamete and recurrent selection with multi-location testing to pyramid white mold resistance. The method also allows concurrent introgression of additional resistance alleles and QTL, and development of white mold resistant dry bean cultivars. Two single crosses involving four white mold resistant dry and snap beans and interspecific breeding lines were made in 2002. These were used to develop one double-cross. One resistant parent in 2003 and two in 2004 were added through conical or sequential crossing. Thus, the base population (WMRSC0) currently being used for the first cycle of recurrent selection (WMRSC1) involves 7 resistance sources. Two to three-stage sequential inoculations are used to select highly resistant plants between and within families for intermating. The S0- and/or S1-based multi-location testing for white mold in the greenhouse and field will be used for the second and subsequent cycles of recurrent selection. The methodology used and results obtained thus far will be discussed.