a b s t r a c tThe levels of nine chlorogenic acids, caffeine, trigonelline and sucrose were determined by HPLC-UV and HPLC-RI systems in wet and semi-dry post-harvested coffee seeds from 17 Brazilian Arabica cultivars and progenies. Coffees processed by wet method showed higher contents of chlorogenic acids (p = 0.02) and trigonelline (p < 0.01), and lower content of sucrose (p = 0.02) compared to those produced by a semi-dry method. Regarding caffeine, no difference was observed between both methods. The implications of the differences observed in the chemical composition of coffee seeds treated by wet and semi-dry methods on cup quality deserve investigation.

Coffee leaf rust (CLR) caused by Hemileia vastatrix Berk. et Br. is one of the major Coffea arabica diseases worldwide. CLR resistance has been attributed to at least nine dominant genes, as single or in combination. We present an inheritance study and mapping loci involved in the Híbrido de Timor (HDT) UFV 443-03 resistance to race I, race II, and pathotype 001 of H. vastatrix. Molecular markers were used to ascertain the phenotypic results and to map the putative resistance loci. For all tree isolates, the inheritance study indicated that the resistance of HDT UFV 443-03 is conditioned by two independent dominant loci or by three independent loci (two dominant and one recessive). Molecular marker analyses ascertained that the resistance of HDT UFV 443-03 to race II is conditioned by at least two independent dominant loci, while the resistance to race I and pathotype 001 is conditioned by at least four independent dominant loci. Gene pyramiding might result in a cultivar with durable resistance; however, it is difficult to distinguish between plants with one or more resistance genes due to epistatic effects. Molecular markers linked to these genes were indicated for marker-assisted selection, as it is an efficient breeding alternative for CLR resistance with no such epistatic effects.

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The coefficient of parentage among 121 cultivars of Coffea arabica L. in Brazil released from 1939 to 2009 was estimated and used to study the genetic diversity and the breeding pattern of the breeding programs. A low genetic diversity was observed within the C. arabica cultivars of Brazil. The genetic base of 121 cultivars released in Brazil between 1939 and 2009 was defined by 13 ancestors. Seven ancestors contribute with 97.55% of the genetic base of C. arabica cultivars. Bourbon Vermelho contributed with 52.76% for the genetic pool of the C. arabica cultivars of Brazil followed by Sumatra (19.05%) and Híbrido de Timor (11.59%). Mundo Novo and Icatu Vermelho contributed with 87.65% for the genetic base of the C. arabica cultivars. It was calculated that 97.55% of the genetic base of the Brazilian C. arabica cultivars is derived from seven ancestors, indicating a narrow genetic base. Among the first progenies, Mundo Novo contributed with 69.39% of the genetic base of C. arabica cultivars in Brazil. The increase in the genetic diversity among C. arabica cultivars observed in recent decades is due to the introduction of parental lines with diverse genetic base. High genetic diversity was observed among cultivars released by Empresa de Pesquisa Agropecuária de Minas Gerais/Universidade Federal de Viçosa, Fundação Procafé, and Instituto Agronômico do Paraná. The 121 Brazilian cultivars were clustered into four groups based on coefficient of parentage. The distributions of genotypes over the cluster groups showed the effect of parental line contribution.

Genomic Selection (GS) has allowed the maximization of genetic gains per unit time in several annual and perennial plant species. However, no GS studies have addressed Coffea arabica, the most economically important species of the genus Coffea. Therefore, this study aimed (i) to evaluate the applicability and accuracy of GS in the prediction of the genomic estimated breeding value (GEBV); (ii) to estimate the genetic parameters; and (iii) to evaluate the time reduction of the selection cycle by GS in Arabica coffee breeding. A total of 195 Arabica coffee individuals, belonging to 13 families in generation of F2, susceptible backcross and resistant backcross, were phenotyped for 18 agronomic traits, and genotyped with 21,211 SNP molecular markers. Phenotypic data, measured in 2014, 2015, and 2016, were analyzed by mixed models. GS analyses were performed by the G-BLUP method, using the RKHS (Reproducing Kernel Hilbert Spaces) procedure, with a Bayesian algorithm. Heritabilities and selective accuracies were estimated, revealing moderate to high magnitude for most of the traits evaluated. Results of GS analyses showed the possibility of reducing the cycle time by 50%, maximizing selection gains per unit time. The effect of marker density on GS analyses was evaluated. Genomic selection proved to be promising for C. arabica breeding. The agronomic traits presented high complexity for they are controlled by several QTL and showed low genomic heritabilities, evidencing the need to incorporate genomic selection methodologies to the breeding programs of this species.

RESUMOAvaliou-se com este trabalho o comportamento de 28 progênies F3 de Coffea arabica obtidas de cruzamentos das cultivares Catuaí Vermelho e Catuaí Amarelo com descendentes do Híbrido de Timor, realizados pela Epamig em conjunto com a UFV. Estimaram-se os parâmetros genéticos e as correlações entre caracteres, buscando conhecer a estrutura genética da população e seu potencial para o melhoramento. O experimento foi instalado em Patrocínio, Estado de Minas Gerais, em delineamento de blocos casualizados com seis repetições, contendo 28 progênies F3 e duas testemunhas da cultivar Catuaí Vermelho IAC 15. Analisaram-se as produções obtidas nas quatro colheitas iniciais, de 1997 a 2000 e alguns caracteres vegetativos. As progênies avaliadas apresentaram média de produção de grãos superior à testemunha, e grande variabilidade genética, sugerindo a possibilidade de se obter linhagens superiores. As progênies avaliadas apresentaram-se resistentes às raças fisiológicas da ferrugem presentes na região do experimento. A progênie 505-9-2 se destaca como material produtivo e vigoroso e de porte alto, enquanto as progênies 514-7-10 e 514-7-6 além de produtivas e vigorosas apresentaram porte baixo semelhante à cultivar Catuaí Vermelho IAC 15. A produção de grãos apresentou correlação genotípica alta e positiva com os caracteres diâmetro do caule, vigor, porte, altura e diâmetro da planta, mas não apresentou resultados consistentes de correlação com carga pendente. A produção de grãos de anos de colheita mostrou-se correlacionada com a produção total de quatro anos apenas a partir do segundo ano de produção.Palavras-chave: café, Coffea arabica L., melhoramento do cafeeiro, Híbrido de Timor.

Um ensaio de competição de linhagens de café (Coffea arábica L. “Catimor”) (Rubiaceae) foi conduzido com o objetivo de estimar as correlações genotípicas e as relações causa-efeito entre a produtividade de café beneficiado e outras características agronômicas. A produtividade de café beneficiado apresentou as maiores correlações com vigor vegetativo, seca de ponteiros e época de maturação. Pela análise de trilha, verificou-se que o maior efeito direto sobre a produtividade de café beneficiado foi do vigor vegetativo, com quem também apresentou a maior correlação. Houve efeito direto de seca de ponteiros sobre produtividade de café beneficiado. Apesar da alta correlação genotípica detectada entre produtividade de café beneficiado e época de maturação, estas não apresentaram relação causa-efeito. A produtividade também não foi influenciada por diâmetro da copa, altura da planta ou curvatura dos ramos

New cultivars are released every year to meet market demands. However, in species with a narrow genetic base, such as Coffea arabica, the cultivars are closely related and phenotypically similar. This hinders the accurate discrimination of genotypes using morphological descriptors in distinctness, uniformity, and stability (DUS) testing, which is required for the registration and protection of new cultivars. In this sense, molecular markers are an auxiliary tool for accurate and precise discrimination of cultivars. This study aimed to verify the informative capacity and effectiveness of a molecular marker set to discriminate among C. arabica varieties, create a database of DNA profiles and allele frequencies, analyze the genetic diversity in this collection, and explore genetic kinships. Thirty-four C. arabica cultivars/progenies, which belong to the Brazilian Cultivar Trial, were analyzed using 31 microsatellite markers. Markers with weak bands were removed, and of the remaining, 74.07% were polymorphic and revealed 47 alleles. The obtained molecular profiles revealed segregation between and within cultivars/ progenies, and genetic variability was observed between all the cultivars/progenies. Sixteen markers were selected for dendrogram construction and for fingerprinting analysis of the cultivars. The ability of these markers to detect varietal mixture and analyze diversity between and within cultivars was also discussed in detail. The results demonstrated the effectiveness of markers in distinguishing related genotypes from those with similar phenotypic traits. This biotechnological tool will assist breeders in DUS testing of cultivars.