Submitted to: Bean Improvement Cooperative Annual Report
Publication Type: Research Notes
Publication Acceptance Date: 11/1/1999
Publication Date: 4/1/2000
Citation: MIKLAS, P.N., SMITH, J.R., RILEY, R., GRAFTON, K.F., SINGH, S.P., JUNG, G., COYNE, D.P. MARKER-ASSISTED BREEDING FOR PYRAMIDED RESISTANCE TO COMMON BACTERIAL BLIGHT. BEAN IMPROVEMENT COOPERATIVE ANNUAL REPORT, 43:39-40. 2000.
Technical Abstract: Common bacterial blight (CBB) caused by Xanthomonas campestris pv. phaseoli is a major disease of dry bean (Phaseolus vulgaris L.). Breeding for high levels of resistance is complicated by poor adaptation of resistant germplasm and low heritability. The resistance sources GN#1 sel 27, XAN 159, and OAC 88-1 each contribute two independent quantitative trait loci (QTL) with major effect for CBB resistance. Allelism among many of these QTL is still unknown. Sequence characterized amplified regions (SCAR) linked with five of the six QTL are available for DNA marker-assisted selection studies. We examined the genomic relationship among QTL conditioning CBB resistance derived from these three sources, and investigated the effectiveness of the SCAR markers for indirect selection for resistance to CBB in bean. Backcross or gamete selection for SCAR markers linked with three independent QTL derived from XAN 159 and GN No. 1 Sel 27 has resulted in advanced cranberry, pinto, and snap bean germplasm with combined resistance to CBB. Thus, use of marker- assisted selection should expedite transfer and accumulation of CBB resistance in other market classes of beans.