5 and introduction line PI207262, tepary bean ( Phaseolus acutifolius L.) introduction lines (PI319443 and PI440795), and scarlet runner bean ( Phaseolus coccineus L.). These sources include the common bean cultivar Montana No. vulgaris and its close relatives in intra- and inter-specific crosses to improve CBB resistance in beans. Over the years, bean breeders have utilized different sources of resistance from P. In practice, host resistance is the most effective and environmentally-sound approach to control CBB. Control measures for CBB include the use of disease-free seed, crop rotation, application of copper-based products and antibiotics, and cultivation of resistant varieties. phaseoli ( Xap), is a serious seed-borne disease in both temperate and tropical bean production zones. In 2006, the bean industry was valued at $1.2 billion and $180 million in USA and Canada, respectively ( ).Ĭommon bacterial blight (CBB), incited by Xanthomonas axonopodis pv. fibre, resistant starch, and oligosaccharides), vegetable protein, important vitamins and minerals like folate and iron as well as antioxidants and only very small amounts of fat. Its nutritional composition includes complex carbohydrates (e.g. It is the most important grain legume for direct human consumption. This study demonstrated that association mapping using a reasonable number of markers, distributed across the genome and with application of plant materials that are routinely developed in a plant breeding program can detect significant QTLs for traits of interest.Ĭommon bean ( Phaseolus vulgaris L.) is a diploid (2n = 2x = 22) annual species, and is predominantly self-pollinating. Furthermore, 12 significant SNP markers were co-localized with or close to the CBB-QTLs identified previously in bi-parental QTL mapping studies. Fourteen markers were significant for both dates and the markers UBC420, SU91, g321, g471, and g796 were highly significant (p ≤ 0.001). Eighteen and 22 markers were significantly associated with CBB rating at 14 and 21 DAI, respectively.
MLM (Mixed Linear Model) analysis, including population structure and kinship, was used to discover marker-trait associations. Kinship analysis also revealed complex familial relationships among all lines, which corresponds with the known pedigree history. The best possible population structure was to assign 36% and 64% of the lines into Andean and Mesoamerican subgroups, respectively. Of the 132 SNPs, 26 SNPs had more than 20% missing data, 12 SNPs were monomorphic, and 17 SNPs had a MAF (Minor Allelic Frequency) of less than 0.20, therefore only 75 SNPs were used for association study, based on one SNP per locus.
All lines were genotyped using 132 SNPs (Single Nucleotide Polymorphisms) evenly distributed across the genome. Of them, 395 lines were evaluated for CBB resistance at 14 and 21 DAI (Days After Inoculation) in the summer of 2009 in an artificially inoculated CBB nursery in south-western Ontario. ResultsĪ population of 469 dry bean lines of different market classes representing plant materials routinely developed in a bean breeding program were used. Unlike conventional QTL discovery strategies, in which bi-parental populations (F 2, RIL, or DH) need to be developed, association mapping-based strategies can use plant breeding populations to synchronize QTL discovery and cultivar development. Host resistance is practically the most effective and environmentally-sound approach to control CBB. phaseoli ( Xap), is a major yield-limiting factor of common bean ( Phaseolus vulgaris L.) production around the world. Common bacterial blight (CBB), incited by Xanthomonas axonopodis pv.
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