Herança e mapeamento genético da resistência do acesso PI 587905 ao isolado monopustular PPUFV02 de Phakopsora pachyrhizi, agente causal da ferrugem asiática da soja

• Ano de defesa: 2012
• Autor(a) principal: Alves, Daniel Pedrosa
• Orientador(a): Brommonschenkel, Sérgio Hermínio
• Banca de defesa: Cunha, Luis Claudio Vieira da
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Genética e Melhoramento
• Departamento: Genética animal; Genética molecular e de microrganismos; Genética quantitativa; Genética vegetal; Me
• País: BR
• Palavras-chave em Português: Soja; Ferrugem asiática da soja; Resistência a doenças; Melhoramento; Phakopsora pachyrhizi
• Palavras-chave em Inglês: Soybean; Asian soybean rust; Disease resistance; Improvement; Phakopsora pachyrhizi
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4764

Asian soybean rust (ASR) caused by Phakopsora pachyrhizi fungus is the most important fungal disease that threatens soybean cultivation. Nowadays the main disease control procedure is administering fungicides from the triazole and strobilurin groups. However, using rust resistant or tolerating varieties is the best alternative for controlling the disease, as it reduces production costs, facilitates dealing with the disease and reduces possible environmental impact caused by usage of fungicides. Until now, five genes were identified in soybean (Rpp1 to 5) that are resistant to P. pachyrzi. However, there are new accesses that feature resistance and which inheritance is unknown. The objective of this work was studying the resistance inheritance of the PI 587905 access to the monopustular isolate PPUFV02 and demonstrating its relationship of the identified gene(s) to already described genes through genetic mapping by using microsatellite markers. A segregating F2 population was obtained for resistance by crossing access PI 587905 with the susceptible cultivar Conquista; this population was made of five subpopulations (23C 1 to 5) from different F1 plants. Plants from 23C-1 F2 population were inoculated in the V2-V3 stage in controlled conditions, with monopustular isolate PPUFV02 of P. pachyrizi and evaluated eight, ten, twelve and fourteen days after inoculation. Segregation pattern indicated that resistance is governed by a gene with partial dominance (χ2 = 1.86 p= 39.48%). Analysis with microsatellite markers indicated that the resistance gene is located in the linkage group G (LG-G) in the interval Sct_187-Sat_064 that contains the Rpp1 locus, suggesting that the resistance gene in access PI 587905 is a part of Rpp1 gene or another linked gene. Subpopulations 23C-2 to 5 were planted with the purpose of obtaining more plants with informative recombination events between the loci Sct_187 and Sat_064. Fenotyping of these plants was made in an identical way to the 23C-1 subpopulation; however genotyping was performed only in susceptible plants. From the group analysis of all subpopulations four F2 plants were obtained. They featured informative recombination events between the loci Sct_187 and Sat_064. Those can be used for deep mapping in this region, aiming to precisely locate the resistance gene and its future positional cloning. Markers Sct_187r2 and Sat_064 will also be suitable for use in assisted selection programs with molecular markers aiming introgression of the resistance gene in PI 587905 and its pyramid connection with other genes resistant to ASR in commercial soybean cultivars.