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URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Item Multiple resistance to bacterial halo blight and bacterial leaf spot in Coffea spp.(Instituto Biológico, 2019) Rodrigues, Lucas Mateus Rivero; Destéfano, Suzete Aparecida Lanza; Almeida, Irene Maria Gatti de; Beriam, Luís Otávio Saggion; Braghini, Masako Toma; Guerreiro Filho, OliveiroBreeding for genetic resistance is an important method of crop disease management, due to the numerous benefits and low cost of establishment. In this study, progenies of 11 Coffea species and 16 wild C. arabica accessions were tested for their response to Pseudomonas syringae pv. garcae, the causal agent of bacterial halo blight, a widespread disease in the main coffee-producing regions of Brazil and considered a limiting factor for cultivation in pathogen-favorable areas; and also to P. syringae pv. tabaci, causal agent of bacterial leaf spot, a highly aggressive disease recently detected in Brazil. Separate experiments for each disease were carried out in a greenhouse, with artificial pathogen inoculations and ideal moisture conditions for disease development. The results showed that C. canephora, C. congensis, C. eugenioides, C. stenophylla, and C. salvatrix progenies, the wild C. arabica accessions Dilla & Alghe and Palido Viridis, and cultivar IPR 102 contain satisfactory levels of simultaneous resistance against bacterial halo blight and bacterial leaf spot. These results are useful in breeding programs for durable resistance to multiple biotic agents, providing new combinations of resistance alleles by hybridization, as well as for phytopathological studies, to identify infraspecific variability of the pathogens.Item Cryopreservation of coffee zygotic embryos: dehydration and osmotic rehydration(Editora UFLA, 2016-07) Pinto, Maísa de Siqueira; Paiva, Renato; Silva, Diogo Pedrosa Corrêa da; Santos, Paulo Augusto Almeida; Freitas, Rodrigo Therezan de; Silva, Luciano CoutinhoConservation of plant genetic resources is important to prevent genetic erosion. Seed banks are the most common method of ex situ conservation; however, coffee seeds can not be stored by conventional methods. Cryopreservation is a viable alternative for long-term conservation of species that produce intermediate or recalcitrant seeds, as coffee. The aim of this work was to cryopreserve Coffea arabica L. cv Catuaí Vermelho IAC 144 zygotic embryos, and analyse the effects of dehydration prior cryopreservation and osmotic rehydration after thawing, in embryos germination and seedlings formation after cryopreservation. Prior to cryopreservation, different dehydration times (0, 15, 30, 60 and 120 min) were tested. Dehydrated embryos were cryopreserved in liquid nitrogen for 1 hour, and after thawing were rehydrated by osmotic solutions. Dehydrated and non-cryopreserved embryos were also analysed. The test with 2,3,5 triphenyl tetrazolium chloride (TTC) was used to evaluate the embryos viability. Non-dehydrated embryos did not survive after freezing. Embryos that were dehydrated until 20% of the moisture content did not germinate when osmotic rehydration was not performed. In contrast, cryopreserved embryos with the same moisture content presented 98% germination when they were rehydrated slowly in osmotic solution. According to tetrazolium tests, embryos presented maximum viability (75%) after dehydration for 60 minutes (23% moisture content). Therefore, coffee zygotic embryos (Coffea arabica L. cv. Catuaí Vermelho) can be successfully cryopreserved using physical dehydration in silica gel for 60 minutes (23% moisture content), followed by osmotic rehydration after thawing. This method allowed a germination of 98% of cryopreserved zygotic embryos.Item Integração de dados quantitativos e multicategóricos na determinação da divergência genética entre acessos de cafeeiro(Instituto Agronômico (IAC), 2013-07) Silva, Felipe Lopes da; Baffa, David Carlos Ferreira; Oliveira, Antonio Carlos Baião de; Pereira, Antonio Alves; Bonomo, Vitor SantosFoi realizada estratégia de integração dos dados quantitativos e multicategóricos para avaliação da divergência genética entre 88 acessos de Coffea arabica. Avaliaram-se 12 características quantitativas (nota total da qualidade sensorial da bebida; peso de três litros de “café da roça”; peso de três litros de “café da roça” com 11% de umidade; porcentagem de café beneficiado a partir de três litros de “café da roça” com 11% de umidade; peso de três litros de café beneficiado com 11% de umidade; total de frutos de “café da roça” em um litro; porcentagem de frutos secos, passas, cereja, verde-cana e verdes em um litro de “café da roça”; e porcentagem de frutos com lojas vazias em um litro de “café da roça”) e seis características multicategóricas relacionadas à qualidade sensorial da bebida (doçura, acidez, corpo, sabor, retrogosto e aspecto geral). Baixa divergência genética foi encontrada entre os acessos considerando as características quantitativas e multicategóricas isoladamente. No entanto, com a conversão dos dados quantitativos em multicategóricos, a integração de características de diferentes naturezas favoreceu a melhor visualização da divergência genética entre os acessos avaliados, devido ao maior número de grupos formados em comparação ao agrupamento para cada conjunto de características.