Resistência de progênies de café Catimor à ferrugem

Abstract

RESUMOVisando avaliar o desempenho de genótipos de café Catimor, foram realizadas avaliações em nível de campo quanto à capacidade produtiva e a incidência da ferrugem e, em casa-de-vegetação os componentes da resistência quantitativa à raça II do patógeno. A reação à infecção foi avaliada por meio de uma escala de notas de 0 a 9, sendo 0 a 3 para plantas consideradas resistentes e 4 a 9 para suscetíveis. Os componentes da resistência quantitativa avaliados foram: freqüência de infecção, esporulação, área foliar lesionada, período de incubação e de latência. As progênies UFV 5550, UFV 6861, UFV 6870, UFV 6831 e UFV 6834 apresentaram produtividade semelhante à da cultivar Catuaí utilizada como testemunha (P < 0,05). Nenhuma planta das progênies UFV 5530, 5451, 5550, 6903 e 5464 apresentou pústulas com esporos. Os descendentes das progênies em estudo variaram quanto à reação à ferrugem, desde resistência completa a alta suscetibilidade, sendo que a maioria situou-se nos níveis intermediários, evidenciando a presença de resistência quantitativa. O número médio de lesões e a área foliar lesionada foram 13 e 21 vezes menores, respectivamente, em UFV 6866. A progênie UFV 6870 apresentou a nota 0,1 de esporulação e a cv. Catuaí, 3,6. O período de incubação nos genótipos estudados variou de 18 a 36 dias e o período latente variou de 20 a 46 dias. Comparado à cultivar Catuaí Vermelho IAC 15, conclui-se que a maioria dos genótipos de Catimor estudados possuem resistência quantitativa. Palavras-chave adicionais: Coffea arabica, Hemileia vastatrix. ABSTRACT Resistance of Catimor to coffee leaf rustTo study the performance of Catimor genotypes, field tests were done to evaluate their productive capacity and rust incidence, while horizontal resistance of seedlings to race II of Hemileia vastatrix was tested in the greenhouse. The reaction to the pathogen was evaluated on a scale of 0 to 9 where: 0 to 3 = resistant plants and 4 to 9 = susceptible plants. The components of quantitative resistance evaluated were: infection frequency, sporulation, lesioned foliar area, incubation period and latent period. Progenies UFV 5550, UFV6861, UFV 6870, UFV6831 and UFV 6834 showed similar productivity to the Catuaí cultivar (P < 0.05). Progenies UFV 5530, UFV 5451, UFV 5550, UFV 6903 and UFV 5464 produced no diseased plants. The descendents of the progenies in this study varied greatly for rust reaction, with continuing variation from full resistance to high susceptibility, with the majority at intermediary levels. This indicates the presence of quantitative resistance in these genotypes. Compared to the Catuaí cultivar, it can be concluded that the studied genotypes had quantitative resistance, with the average number of lesions and lesioned foliar area 13 to 21 times less, respectively, on UFV 6866. The sporulation of UFV 6870 reached 0.1, a very low score if compared to Catuaí's score of 3.6. The incubation period of the studied genotypes varied from 18 to 36 days and the latent period from 20 to 46 days. Compared to the Catuaí Vermelho...

Productivity and Sensory Quality of Arabica Coffee in Response to Pruning Type ‘Esqueletamento’

“…It is worth mentioning the genotype 16, being the only descendant of the "Hibrido de Timor" with high percentage of leaf rust , being able to be explained by the occurrence of break of resistance of this genotype by some physiological races of the fungus present in the region, where the local environment may have been conducive to this break. Costa et al (2007) mentioned that the "Hibrido de Timor" can be used as a source for vertical and/or horizontal resistance in genetic improvement programs, in order to obtain cultivars resistant to leaf rust. Reis (2016) confirms the high incidence of leaf rust in the cultivars Catucaí Amarelo 24/137 (38%) and Catucaí Vermelho 20/15 (42%), but still lower than the values found for the genotypes of this study, showing that there is resistance breaking for physiological races of the fungus present in the region.…”

Agronomic characterization and responses to coffeeleaf rust in coffee progenies resistant to the gall nematode Meloidogyne exigua

“…All progenies showed low AUCRIP and AUCRSP values for both harvests and therefore have the potential for resistance to coffee rust. The presence of the coffee rust resistance allele in progenies of the Timor Hybrid germplasm has already been demonstrated by various authors (COSTA et al, 2007) Horizontal resistance is a disease control measure that is highly desired by researchers because it is both durable and efficient against multiple strains of a specific pathogen. Table 2 shows that no progeny had high resistance to nonsporulating rust.…”

“…Progeny with horizontal resistance cannot be selected from those without disease incidence, since the latter most likely have vertical or specific resistance which, according to Botelho et al (2010 b), masks the expression of horizontal resistance. Costa et al (2007) also proposed the existence of quantitative or horizontal resistance when studying Catimor (Caturra × Timor Hybrid) progeny. They showed that the Timor Hybrid could be used as source of vertical and/or horizontal resistance in genetic breeding programs aimed at preparing rust-resistant cultivars.…”

“…et Br. (COSTA et al, 2007;PAIVA et al, 2010;DEL GROSSI et al, 2013) and to gall nematodesMeloidogyne spp. (BARBOSA et al, 2010;REZENDE et al, 2013).…”

“…The Timor Hybrid (TH), most likely a natural cross between Coffea Arabica and C. canephora Pierre ex A. Froehner, is a source of genetic material for the development of new cultivars (RODRIGUES JÚNIOR et al, 2004). It is resistant both to the causative agent of coffee leaf rust (COSTA et al, 2007) and the gall nematode .…”