title: Identification and mapping of resistance genes to Phakopsora pachyrhizi in soybean (Glycine max L.) accession PI 594767-A.
abstract: The goal of this study was to study resistance inheritance in the soybean (Glycine max L.) accession PI 594767-A to the Phakopsora pachyrhizi isolate PPUFV02, and map the resistance gene(s) identified using microsatellite markers. Crosses between PI 594767-A and the susceptible cultivar 'Conquista' gave rise to the segregating subpopulations 26C-2 and 26C-5, which in the F2 generation were evaluated for their reactions to PPUFV02. In addition, analyses with microsatellite markers linked to the Rpp1-Rpp5 loci were also performed. The segregation pattern obtained in 26C-2 revealed that resistance was governed by a recessive gene; a 1:2:1 segregation pattern was observed in 26C-5, indicating control by a gene with partial dominance. This variability may have been caused because environmental conditions, particularly temperature, when 26C-5 was assessed were unfavorable for pathogen development, allowing the phenotypic expression of heterozygous alleles in PI 594767-A. A resistance gene was located in the soybean linkage group G, in the genomic region between Sct_187r2 and Sat_064 that contains the Rpp1 locus. Resistance in PI 594767-A is probably conferred by a new Rpp1 gene allele, because this accession has a haplotype for Sct_187r2 and Sat_064, which differs from haplotypes of accessions that also contain resistance alleles that map the Rpp1 locus. The use of Sct_187r2 and Sat_064 will facilitate the introgression of the resistance allele from PI 594767-A and its pyramiding with other resistance genes into genotypes with superior agronomic characteristics, in order to obtain cultivars with broad-spectrum resistance to P. pachyrhizi.
authors.affiliation: Programa de Pós-Graduação em Genética e Melhoramento, Laboratório de Genômica, Universidade Federal de Viçosa, Viçosa, MG, Brasil gafrocha@usp.br.
authors.forename: G A F
authors.initials: GA
authors.lastname: Rocha
authors.affiliation: Programa de Pós-Graduação em Genética e Melhoramento, Laboratório de Genômica, Universidade Federal de Viçosa, Viçosa, MG, Brasil.
authors.forename: D P
authors.initials: DP
authors.lastname: Alves
authors.affiliation: Programa de Pós-Graduação em Genética e Melhoramento, Laboratório de Genômica, Universidade Federal de Viçosa, Viçosa, MG, Brasil.
authors.forename: J C
authors.initials: JC
authors.lastname: Oliveira
authors.forename: S H
authors.initials: SH
authors.lastname: Brommonschenke
mesh_terms: D000483:Alleles; D002874:Chromosome Mapping; D060467:Disease Resistance / Q000235:genetics*; D059647:Gene-Environment Interaction; D017343:Genes, Plant; D005838:Genotype; D000067563:Phakopsora pachyrhizi; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology*; D013025:Glycine max / Q000235:genetics* / Q000382:microbiology*