Caracterização molecular e resistência do cafeeiro Híbrido de Timor à Hemileia vastatrix

• Autor(a) principal: Silva, Rosemeire Alves da
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4423
• topic: Resistência; Marcador molecular; Banco de germoplasma; Resistance; Molecular marker; Genebank; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA

Coffee is a major export product from Brazil having high importance for the country's economy. Thus, it becomes necessary to develop technologies to improve the Brazilian coffee farming. The main disease problem affecting coffee production is the coffee rust, a disease caused by the biotrophic fungus Hemileia vastratrix. The use of resistant varieties has been one of the main measures used to control the disease. One of the most used sources to obtain resistant varieties is the Híbrido Timor. Hence, the characterization the and understanding of the resistance of available accessions of Híbrido Timor to H. vastratrix are essential for the comprehension of the genetic basis of the resistance to this disease and to assist in the choice of genotypes to be used in breeding programs aimed at obtaining cultivars with durable resistance to rust. In this work, the germplasm bank of the Federal University of Viçosa, containing 152 accessions of Híbrido Timor and 6 genotypes from the EPAMIG breeding program were molecularly characterized and analyzed for resistance to two races of H. vastratrix, namely II and XXXIII. For the molecular characterization, 29 microsatellite primers were used and 92 bands were obtained with an average of 3.17 bands per primer. Of the 92 total bands obtained, 75 were polymorphic. Five primer combinations of AFLP were utilized by which 126 polymorphic bands were obtained with an average of 25.2 bands per combination of primer. Using only the data from microsatellite markers and the grouping based on the arithmetical complements of Jaccard and the UPGMA method, it was possible to separate 151 genotypes. Seven accessions did not differ, namely UFV 450-06, UFV450-12, UFV 428-01, UFV 428-02, UFV427-15, UFV427-90 and UFV428-04. By adding the data from the dominant markers AFLP, it was possible to separate these individuals, not only discriminating the accessions 427-90 and 428-04. It was possible to determine a unique molecular pattern (fingerprinting) for each individual using 58 marks. For the phenotypic characterization, the races II and XXXIII were inoculated in the152 accessions Híbrido Timor and 6 genotypes improving EPAMIG. All accessions were resistant to race II, which shows that the accessions may have either only one resistance gene, but not SH5, or more than one gene which may be any combination of SH 5, 6, 7, 8 e 9. With the race XXXIII, 14 accessions were susceptible. The race XXXIII presents more than one virulence gene which was able to overcome he resistance of the accessions UFV376-01, UFV376-02, UFV 376-08, UFV 376-09, UFV 376-14, UFV 376-37, UFV 377-51, UFV 408-10,UFV 408-18, UFV 432-30, UFV 445- 70, 2 II P6, 12 III P6 and 22 IV P6. This accessions contain the genes SH5,7 or SH 5,7 e 9. We conclude that 140 accessions of Híbrido Timor remain a good source of resistance to the races II and XXXIII and three materials from the EPAMIG/UFV program were susceptible the race XXXIII.