Caracterização fenotípica e molecular da resistência do cafeeiro Híbrido de Timor a Hemileia vastatrix

• Ano de defesa: 2010
• Autor(a) principal: Pestana, Kátia Nogueira
• Orientador(a): Sakiyama, Ney Sussumu
• Banca de defesa: Cruz, Cosme Damião , Zambolim, Laércio
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Coffea; Ferrugem do cafeeiro; Herança da resistência; Marcadores moleculares
• Palavras-chave em Inglês: Coffea; Coffee rust; Resistance inheritance; Molecular markers
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MELHORAMENTO VEGETAL
• Link de acesso: http://locus.ufv.br/handle/123456789/4538

In order to support the breeding programs coffee that to aim to obtain cultivars resistant to rust (Hemileia vastatrix), this work aimed to study the resistance inheritance of Híbrido de Timor UFV 443-03 and identify molecular markers linked characterized genes. To study the inheritance were evaluated three populations originated from cross the Híbrido de Timor UFV 443-03 resistant parent and Catuaí Amarelo (UFV 2148-57) susceptible cultivar. These plants analyzed, 243 correspond to an F2 population of 114 susceptible backcrossing (BCs) and 87 resistant backcrossing (BCr). Inoculation was performed with a spore suspension (2mg/mL) isolated from the Race I of H. vastatrix in leaf discs, with three replicates for the F2 and RCs, and two for RCr. Plants of the Catuaí Amarelo UFV 2148-57 were susceptible in all inoculations, while the Híbrido de Timor UFV 443-03, the plant F1 and the BCr plants were resistant. Segregation analysis of F2 populations obtained two significant cases, the resistance of a coffee Híbrido de Timor UFV 443-03 the H. vastatrix was governed by two independent and dominant genes (15:1, P = 63.10) and the other three genes is conferred by two dominant and one recessive (61:3, P = 8.87). Plants of the BCs were used to confirm the segregation patterns, which segregated in a rate of 3:1 (P = 74.56), expected segregation for two and three genes. This result demonstrate that the resistance of the Híbrido de Timor is conditioned by two dominant independent genes or three independent genes (two dominant and one recessive). As was found oligogenic inheritance (two or three genes), for confirmation and identification of molecular markers linked to genes, they were treated as QTL, and then located in link genetic map. For this, subjects in the F2 population were analyzed with a total of 110 molecular markers. As 16 markers showed distortion of Mendelian segregation expected rate, the map was constructed with 94 markers (62 AFLP, 28 SSR and 4 RAPD). Whereas a LOD score minimum of three and of 40% recombination maximum, the markers were grouped into 11 linkage groups covering a distance 964.31 cM of the genome, with 13 markers not in any of the linkage groups formed. The longest interval between two markers was 32.1 cM and 68.57% of the markers did not exceed 20 cM. The characterization and identification of QTLs were performed by simple mark and simple interval methods. Methodology of the simple mark was possible to identify markers five associated with QTLs by the methods of ANOVA, regression and maximum likelihood. These QTLs were confirmed by simple interval methodology by means of regression and maximum likelihood. Two QTLs were identified in a 2 linkage group the 0 cM marker 21a, explaining 9.6% of the phenotypic variation. The other was located in 3 linkage group to 13 cM marker 43a, explaining 9.3% of the phenotypic variation. These two QTLs confirm the number and position in the coffee resistance Híbrido de Timor UFV 443-03 H. vastatrix is governed by two independent and dominant genes, thus demonstrating the importance of genomics to identify them. It should be noted that the information obtained in this study are unique to coffee, which may be useful in breeding programs based on assisted selection and positional cloning of the gene for rust resistance. So, should provide support for future breeding populations to obtain more productive and resistance.