“MOLECULAR MAPPING OF Rpp4 RESISTANCE GEN TO ASIAN SOYBEAN RUST IN AN ISOLINE OF THE CULTIVAR WILLIAMS 82”

CAMBURSANO, M.V.; PIOLI, R. N.; CHIESA, M.A; CAIRO, C. A; DALLA, N.T.; VIEIRA, E.S.N.; MIORANZA, F.; SCHUSTER, I.; MORANDI E. N

Beijing, China

Conferencia; VIII World Soybean Research Conference (WSRC VIII); 2009

Institute of Crop Science & Chinese Academy of Agriculture Sciences

Asian Soybean Rust (ASR), caused by the fungus Phakopsora pachyrhisi (PP), is considered today one of the diseases more devastating of the soybean culture. Five distinct major genes conferring resistance against ASR (Rpp1 to Rpp5), have been reported. The stacking of the different genes Rpp in a single cultivar would provide a resistance more sustainable to PP in time. The use of molecular markers (MM) linked to these genes would greatly facilitate this task. Recently, the gene Rpp4 was mapped in the original genotype bearer of this gene. The objective of this work was validating this information in a different genetic background. In addition, the relationship between the dose of allele Rpp4 and the degree of sporulation was investigated. For the analysis of genetic linkage a population of 171 individuals F2:3 from the crossing between the isolines W0 (rpp/rpp) (Williams 82) x W4 (Rpp4/Rpp4) (L87-0842), and MM type SSR available on the public map of soybean were used. As expected, the segregation of the gene Rpp4 in the population accounted for the presence of a simple dominant gene (1:2:1) (P=71.05ns). The gene Rpp4 was linked to the MM Satt288 at a distance of 12.6 cM on the GL G of the soybean genome, confirming the published results. In addition, it was observed a relationship between the dose of the dominant allele of Rpp4 gene and the level of sporulation, with minor sporulation for the genotype homozygous dominant (P=0.016). Keywords mapping, resistance gene, soybean rust