DNA marker-assisted selection to pyramid rust resistance genes in “carioca” seeded common bean lines

The breeding and cultivation of resistant wheat varieties is an effective way of controlling leaf rust ( Puccinia triticina Eriks.). The use of molecular markers facilitates the incorporation of the major leaf rust resistance genes ( Lr genes) responsible for resistance into new varieties and the pyramiding of these genes. Marker-assisted selection was used to incorporate the Lr genes currently effective in Hungary ( Lr9 , Lr24 , Lr25 , Lr29 ) into winter wheat varieties. The Lr genes were identified using STS, SCAR and RAPD markers closely linked to them. Investigations were made on how these markers could be utilised in plant breeding, and near-isogenic lines resembling the recurrent variety but each containing a different Lr gene were developed to form the initial stock for the pyramiding of resistance genes. The results indicate that the marker-assisted selection technique elaborated for resistance genes Lr24 , Lr25 and Lr29 can be applied simply and effectively in wheat breeding, while the detection of the Lr9 marker is uncertain.

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Fine mapping of Ur-3, a historically important rust resistance locus in common bean

10.1101/078782 ◽

2016 ◽

Author(s):

O.P. Hurtado-Gonzales ◽

G. Valentini ◽

T.A.S Gilio ◽

A.M. Martins ◽

Q. Song ◽

...

Keyword(s):

Common Bean ◽

Resistance Genes ◽

Fine Mapping ◽

Rust Resistance ◽

Bulked Segregant Analysis ◽

Snp Markers ◽

Resistance Locus ◽

Bean Rust ◽

Rust Pathogen ◽

Rust Resistance Genes

AbstractBean rust is a devastating disease of common bean in the Americas and Africa. The historically important Ur-3 gene confers resistance to many races of the highly variable bean rust pathogen that overcome all known rust resistance genes. Existing molecular markers tagging Ur-3 for use in marker assisted selection produce false results. We described here the fine mapping of Ur-3 for the development of highly accurate markers linked to this gene. An F2 population from Pinto 114 × Aurora was evaluated for its reaction to four different races of the bean rust pathogen. A bulked segregant analysis using the SNP chip BARCBEAN6K_3 positioned the approximate location of the Ur-3 locus to the lower arm of chromosome Pv11. Specific SSR and SNP markers and haplotype analysis of 18 sequenced bean lines led to position the Ur-3 locus to a 46.5 Kb genomic region. We discovered a KASP marker, SS68 that was tightly linked to the Ur-3 locus. Validation of SS68 on a panel of 130 diverse common bean lines and varieties containing all known rust resistance genes revealed that it was highly accurate producing no false results. The SS68 marker will be of great value to pyramid Ur-3 with other rust resistance genes. It will also reduce significantly time and labor associated with the current phenotypic detection of Ur-3. This is the first utilization of fine mapping to discover markers linked to a rust resistance in common bean.

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