Identificação de fontes e herança da resistência à ferrugem asiática da soja no feijoeiro-comum

• Autor(a) principal: Dessaune, Suelen Nogueira
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4716
• topic: Phakopsora pachyrhizi; Ferrugem da soja; Feijoeiro-comum; Resistência; Marcadores microssatélites; Phakopsora pachyrhizi; Soybean rust; Common bean; Resistance; Microsatellite markers; CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA VEGETAL

Since 2001, when it was first detected in Brazil, the asian soybean rust (ASR), incited by the fungus Phakopsora pachyrhizi, has caused serious damages to the soybean crop. The use of resistant cultivars is the most appropriate control measure as it is more effective, safer and less expensive than the chemical control. A factor that has hampered the identification of resistant cultivars to ASR is the high severity and variability of the pathogen. P. pachyrhizi has a wide host range, including the common bean (Phaseolus vulgaris). ASR has already been detected in bean genotypes under natural conditions in Brazil and in other countries. Thus, in the future, this disease could also become a problem for the bean crop. Therefore, the objectives of this work were to characterize common bean genotypes in relation to their reaction to ASR and to determine the resistance inheritance mode in the PI 181996. And also to search for microsatellite markers (SSR) linked to the resistance gene present in PI 181996. Twelve bean genotypes were tested for their reaction to P. pachyrhizi. The soybean accessions PI 200492, PI 547878, PI 462312 and PI 459025 were also tested. They harbor the resistance genes Rpp1, Rpp2, Rpp3 and Rpp4, respectively. For determination of the inheritance pattern, an F2 population was obtained from the cross PI 181996 X US Pinto 111 (susceptible to ASR). All genotypes, and the F2 plants were inoculated with a single-spore P. pachyrhizi isolate. To identify molecular markers linked to the resistance gene present in PI 181996, 173 SSR primer-pairs were analyzed. Twelve common bean genotypes and four soybean Pis were tested for resistance to ASR. Three of the common bean genotypes were considered resistant and the other nine and all four soybean accessions were susceptible to ASR. Thechi-squared test showed that resistance to ASR in the common bean plant accession PI 181996 is monogenic and dominant. The use of the bulked segregant analysis technique did not detect any SSR marker linked to the ASR resistance gene present in common bean PI181996. A greater number of SSR primers needs to be tested to detect potential markers associated with this gene. This type of information has great importance for breeding programs because it can allow a prompt transfer of this resistance gene to common bean commercial cultivars, minimizing future damage that soybean rust could cause to the bean crop.