ABSTRACT. Coffee outturn can be defined as the ratio between the harvested coffee and its respective processed grains. This character is greatly influenced by genotypic and environmental effects, and in breeding programs your analysis is costly and time-consuming. In this sense, the use of an outturn index to estimate coffee yield on experimental plots is a desirable measure aiming at reducing resources and time in postharvest evaluations. Thus, the present study aimed to evaluate the accuracy of the use of an outturn index equal to 4.0, in the estimation of Conilon coffee grains production. This index indicates that four kilograms of harvested fruit would be needed to obtain one kilogram of processed grains. Based on the average of 157 genotypes conducted in three trials and four harvests, we evaluated the relationship between harvested fruits and processed grains (FcBe), the observed (OGY), and the estimated grain yield per plant (EGY) based on FcBe equal to 4.0 (an outturn index). Descriptive statistics, adequation test for EGY, and the coincidence of occurrence of genotypes observations relating to the top 20% of all observations of OGY and EGY. In the estimation of grain yield in Conilon, the use of FcBe equal to 4.0 showed high precision in the average of the analyzed trials. However, further studies should be conducted to elucidate the effects of climate variables on the yield of Conilon coffee, especially in atypical crop years. Thus, the use of an outturn index becomes interesting in cases where the number of genotypes to be evaluated is very large and a screening of the promising ones is desirable.

ABSTRACT: The biotrophic fungus Hemileia vastatrix causes coffee leaf rust (CLR), one of the most devastating diseases in Coffea arabica . Coffee, like other plants, has developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs) have been identified in certain plants as candidates for resistance ( R ) genes or membrane receptors that activate the R genes. The RGAs identified in different plants possess conserved domains that play specific roles in the fight against pathogens. Despite the importance of RGAs, in coffee plants these genes and other molecular mechanisms of disease resistance are still unknown. This study aimed to sequence and characterize candidate genes from coffee plants with the potential for involvement in resistance to H. vastatrix . Sequencing was performed based on a library of bacterial artificial chromosomes (BAC) of the coffee clone ‘Híbrido de Timor’ (HdT) CIFC 832/2 and screened using a functional marker. Two RGAs, HdT_LRR_RLK1 and HdT_LRR_RLK2, containing the motif of leucine-rich repeat-like kinase (LRR-RLK) were identified. Based on the presence or absence of the HdT_LRR_RLK2 RGA in a number of differential coffee clones containing different combinations of the rust resistance gene, these RGAs did not correspond to any resistance gene already characterized (SH1-9). These genes were also analyzed using qPCR and demonstrated a major expression peak at 24 h after inoculation in both the compatible and incompatible interactions between coffee and H. vastatrix . These results are valuable information for breeding programs aimed at developing CLR-resistant cultivars, in addition to enabling a better understanding of the interactions between coffee and H. vastatrix .

Abstract The specialty coffee market has grown significantly in the past decades and has several cultivars with productive potential. The objective of this study was to evaluate the sensory profile of the beverage produced from Coffea arabica L. genotypes based on postharvest processing and to identify cultivars with the greatest genetic potential for coffee cultivation in the city of Araponga, Minas Gerais, Brazil. The experiment was a randomized complete block design with two replicates and 11 genotypes with different levels of resistance to rust. The sensory profile demonstrated an interaction between the genotype and the processing technique. Five of the genotypes presented total scores above 85 points according to the SCAA protocol. Moreover, two of these genotypes yielded heightened sensory notes after undergoing dry processing. The selection of coffee genotypes should consider the level of technology involved in the drying of the coffee beans, which preserves the potential quality of the beverage.

Abstract Coffee tree is a shrub with dimorphic branches. The orthotropic stem grows vertically with two near-horizontal plagiotropic branches, per node, in opposite phyllotaxy. The consecutive nodes of the orthotropic stem are organized in parastichies. We report here mutant plants of Coffea arabica with triple plagiotropic branch, resulted from the whorled phyllotaxy of the orthotropic stem. In mutant plants three plagiotropic branches in the same node are separated by angles of approximately 120o, while in normal plants two plagiotropic branches in the same node are separated by angles of approximately 180o. In mutant plants the angles of the parastichies increase approximately 50o clockwise between consecutive nodes, while in normal plants the angles increase approximately 87o. The plant architecture is changed. The triple plagiotropic branch is a putative mutant with potential to be explored in coffee breeding programs. The hypotheses for the origin of the mutation and the research perspectives are discussed.

RESUMO Os cafés especiais podem ser diferenciados por diversas formas, incluindo as condições ambientais em que são produzidos e a composição sensorial da bebida. Objetivou-se avaliar neste trabalho o efeito dos fatores altitude, face de exposição solar e cor do fruto nos atributos sensoriais dos cafés da região das Matas de Minas. Nas lavouras, pontos amostrais foram georreferenciados em quatro extratos de altitude (< 700 m; 700 ≤ x ≤ 825 m, 825 < x < 950 m e ≥ 950 m); duas cores de fruto da variedade Catuaí (amarelo e vermelho); e duas faces de exposição solar (Noroeste e Sudeste ). Foram utilizados cafés no estádio "cereja", que foram beneficiados e submetidos à análise sensorial. Foram avaliados os atributos sensoriais percepção geral, bebida limpa, balanço, retrogosto, doçura, acidez, corpo e sabor, compondo assim o escore final. As notas foram submetidas à ANOVA e as médias comparadas pelo teste de Tukey (p ≤ 0,05). Do ponto de vista sensorial, os frutos de café de ambas as cores se mostram semelhantes, assim como os cafés localizados em ambas as faces quando esses fatores foram analisados isoladamente. Entretanto, em maiores altitudes o café Catuaí Amarelo produz cafés de melhor qualidade sensorial. Da mesma forma, os cafés da face Noroeste, em maiores altitudes produzem cafés de melhor qualidade. A altitude é o fator que mais interfere na qualidade dos cafés da região. A atuação em conjunto de todos os fatores contribui para a qualidade final da bebida produzida nas Matas de Minas.

ABSTRACT Specialty coffees can be differentiated in various ways, including the environmental conditions in which they are produced and the sensory composition of the drink. This study aimed to evaluate the effect of altitude, slope exposure and fruit color on the sensory attributes of cafes of the region of Matas de Minas. Sampling points were georeferenced in four altitude ranges (< 700 m; 700 ≤ x ≤ 825 m, 825 < x < 950 m and ≥ 950 m) of the coffee crop; two fruit colors of var. Catuaí (yellow and red); and two slope exposures (North-facing and South-facing). Coffee fruit at the cherry stage were processed and submitted to sensory analysis. The sensory attributes evaluated were overall perception, clean cup, balance, aftertaste, sweetness, acidity, body and flavor, which made up the final score. The scores were examined by ANOVA and means were compared by the Tukey test (p ≤ 0.05). From the sensory standpoint, coffee fruits of both colors are similar, as well as the coffees from both slope exposures when these factors were analyzed separately. However, at higher altitudes, Yellow Catuaí produces coffees with better sensory quality. Similarly, coffees from North-facing slopes, at higher altitudes produce better quality cup. The altitude is the main factor that interferes with coffee quality in the area. All factors together contribute to the final quality of the beverage produced in the region of Matas de Minas.

Ao longo das três últimas décadas os estudos sobre os marcadores moleculares alcançaram avanços extraordinários, em especial nas técnicas de sequenciamento e bioinformática. A seleção assistida por marcadores tornou-se parte da rotina dos programas de melhoramento de importantes empresas de sementes, com o objetivo de acelerar e otimizar o processo de desenvolvimento de novas cultivares. Empresas privadas de sementes crescentemente adotam a seleção assistida por marcadores, especialmente para as espécies de grande importância para o mercado de sementes, como milho, soja e girassol. Nas instituições públicas brasileiras poucos programas de melhoramento a adotam eficientemente. As possíveis razões são: falta de "know-how", falta de laboratório adequado, poucos marcadores validados, alto custo e falta de urgência na obtenção de cultivares. Neste artigo são analisados o uso e as limitações da seleção assistida por marcadores nos programas de melhoramento de plantas dos institutos públicos brasileiros.

Over the past three decades, molecular marker studies reached extraordinary advances, especially for sequencing and bioinformatics techniques. Marker-assisted selection became part of the breeding program routines of important seed companies, in order to accelerate and optimize the cultivar developing processes. Private seed companies increasingly use marker-assisted selection, especially for the species of great importance to the seed market, e.g. corn, soybean, cotton, and sunflower. In the Brazilian public institutions few breeding programs use it efficiently. The possible reasons are: lack of know-how, lack of appropriate laboratories, few validated markers, high cost, and lack of urgency in obtaining cultivars. In this article we analyze the use and the constraints of marker-assisted selection in plant breeding programs of Brazilian public institutes.

Este trabalho objetivou caracterizar acessos de C. canephora oriundos de cultivos comerciais e bancos de germoplasma brasileiros. Um total de 130 acessos das coleções do IAC (São Paulo), UFV (Minas Gerais) e coletados em plantios comerciais no Espírito Santo e Rondônia foram genotipados com 20 novos microssatélites. Métodos multivariados foram utilizados para estimar a relação entre os acessos. Foi observado alto nível de polimorfismo e dois grupos foram identificados: o primeiro foi constituído pelos genótipos conservados nas coleções de germoplasma do IAC e UFV e o segundo foi composto pelos acessos coletados em plantios comerciais. Os acessos do Espírito Santo e de Rondônia formaram dois subgrupos distintos. Apesar do grande polimorfismo encontrado nas lavouras brasileiras de café canéfora, incrementar essa diversidade é necessário, pois um novo limiar de ganhos genéticos é esperado nos programas de melhoramento com a intensificação do uso do germoplasma conservado.

This work aimed to characterize accessions that represent the C. canephora germplasm conserved and cultivated in Brazil. A total of 130 accessions from germplasm banks of IAC (São Paulo), UFV (Minas Gerais) and also collected in plantations of the State of Espírito Santo and Rondônia were evaluated with a set of 20 new microsatellite primers. Multivariate methods were used to estimate the relationship among the accessions. High level of polymorphism and two major diversity clusters were identified. First cluster was composed by the accessions conserved in the IAC and UFV collections and the second was formed by accessions collected in areas under cultivation. Accessions from Espírito Santo and Rondônia were clear separated, composing two subclusters. Despite the great polymorphism found in Brazilian plantations, the diversity may be increased, because a new threshold in the genetic gains is expected on breeding programs with the intensification of the use of conserved germplasm.

O objetivo deste trabalho foi identificar marcadores moleculares relacionados à resistência do cafeeiro (Coffea arabica) à ferrugem (Hemileia vastatrix). Foram identificadas sequências de DNA potencialmente envolvidas na resistência do cafeeiro a doenças, por meio de análise "in silico", a partir das informações geradas pelo Projeto Brasileiro do Genoma Café. A partir das sequências mineradas, foram desenhados 59 pares de iniciadores para amplificá-las. Os 59 iniciadores foram testados em 12 cafeeiros resistentes e 12 susceptíveis a H. vastatrix. Vinte e sete iniciadores resultaram em bandas únicas e bem definidas, enquanto um deles amplificou fragmento de DNA em todos os cafeeiros resistentes, mas não nos suscetíveis. Esse marcador molecular polimórfico amplificou uma região do DNA que corresponde a uma janela aberta de leitura parcial do genoma de C. arabica que codifica uma proteína de resistência a doenças. O marcador CARF 005 é capaz de diferenciar os cafeeiros analisados em resistentes e susceptíveis a H. vastatrix.

The objective of this work was to identify molecular markers related to the resistance of coffee (Coffea arabica) to rust (Hemileia vastatrix). DNA sequences potentially involved in coffee disease resistance were identified, using "in silico" analysis, from data obtained by the Brazilian coffee genome project. After data mining, 59 primer pairs were designed to amplify the sequences identified. The 59 primers were tested on 12 resistant and 12 susceptible coffee plants to H. vastatrix. Twenty-seven primers resulted in unique and well-defined bands, while one of these amplified a DNA fragment in all resistant plants, but not in the susceptible ones. This polymorphic molecular marker amplified a region of DNA that corresponds to a partial open reading frame of C. arabica genome that encodes a disease resistance protein. The marker CARF 005 can be used to differentiate between resistant and susceptible coffee plants to H. vastatrix.

O estudo da eficiência nutricional de plantas enxertadas de cafeeiro é importante para a seleção de combinações enxerto/porta-enxerto, visando atingir melhor desenvolvimento e produção. Este trabalho teve como objetivo avaliar as diferenças na eficiência de absorção e utilização de B, Zn, Cu e Mn em mudas enxertadas de cafeeiro. O experimento foi conduzido em vasos de 20 litros contendo como substrato terra, areia e esterco na proporção de 3:1:1, onde as plantas permaneceram por um período de 18 meses. Utilizaram-se como enxerto quatro genótipos de Coffea arabica L.: os cultivares Catuaí-Vermelho IAC 15 ('Catuaí 15') e Oeiras MG 6851 ('Oeiras') e os híbridos H419-10-3-4-4 ('H419') e H514-5-5-3 ('H514') do programa de melhoramento da EPAMIG/UFV. Como porta-enxerto foram empregados cinco progênies de famílias de meio-irmãos de clones de Coffea canephora Pierre ex Froenher cv. Conilon: ES 21, ES 36, ES 26, ES 23 e ES 38 do programa de melhoramento de café robusta do Incaper. O delineamento experimental foi inteiramente casualizado, com 24 tratamentos e três repetições, sendo quatro pés-francos e 20 combinações de enxertia. A eficiência nutricional das plantas variou conforme a combinação enxerto/porta-enxerto. O cultivar Oeiras não foi beneficiado por nenhuma enxertia, apresentando redução da produção total de matéria seca em todas as combinações comparativamente ao respectivo pé-franco. O cultivar Catuaí 15 foi mais eficiente na produção de matéria seca e utilização de B e Zn quando combinado com os materiais genéticos de conilon ES 26 e ES 23.

Studying nutritional efficiency of grafted coffee plants is important for the selection of graft/ rootstock combinations, aiming to achieve better plant development and yield. The objective of this work was to evaluate the genetic differences for B, Zn, Cu and Mn absorption and utilization efficiencies of grafted coffee seedlings. The experiment was conducted with seedlings planted in 20 L pots with a substrate consisting of soil, sand, and manure in the proportion of 3:1:1, in which they kept for 18 months, until harvest. Four genotypes of Coffea arabica L. were used as grafts: cultivars Catuaí Vermelho IAC 15 ('Catuaí 15) and Oeiras MG 6851 ('Oeiras'), and hybrids H419-10-3-4-4 ('H419') and H514-5-5-3 ('H514'). All genotypes were obtained from the EPAMIG/UFV breeding program. Five half-sibling progenies of clones of Coffea canephora Pierre ex Froenher cv. Conilon were used as rootstocks: 'ES 21', 'ES 36', 'ES 26', 'ES 23' and 'ES 38, which were obtained from the INCAPER robusta coffee breeding program. The experiment was arranged in a complete randomized design, with 24 treatments and 3 repetitions, using four control plants and 20 grafting combinations. The nutritional efficiency of coffee plants varied according to the graft/rootstock combination. Considering that all combinations promoted dry matter yield decrease when compared with the respective non-grafted plants, cultivar Oeiras MG 6851 was not benefited by any graft. Cultivar Catuaí Vermelho IAC 15 was more efficient in dry matter production and Cu and Mn utilization when combined with conilon rootstocks 'ES 26' and 'ES 23'.

O crescimento e a produção de plantas de C. arabica, em função do porta-enxerto, foi avaliado em condições de campo, em Paula Cândido - MG. Utilizaram-se como enxerto quatro genótipos de C. arabica: as variedades Catuaí Vermelho IAC 15 e Oeiras MG 6851 e as progênies H 419-10-3-1-5 e H 514-5-5-3, e, como porta-enxerto, três genótipos de Coffea canephora Pierre ex A.Froenher: Apoatã LC 2258, Conilon Muriaé-1, sementes oriundas de um campo de recombinação entre os clones de variedade Robustão Capixaba (EMCAPA 8141) e o genótipo de C. arabica: Mundo Novo IAC 376-4, além da utilização de quatro pés-francos. A enxertia em cafeeiro pode influenciar o desenvolvimento das plantas, quando se compararam diferentes combinações enxerto/porta-enxerto com os respectivos pés-francos.Em plantas de cafeeiro enxertadas de seis anos, as combinações de enxertia Catuaí 15/Conilon, Oeiras/Apoatã, Oeiras/EMCAPA e H419/EMCAPA suplantaram os respectivos pés-francos na produção de café.

The effect of rootstocks on vegetative growth and yield of coffee plants (C. arabica) were evaluated under field condition at Paulo Cândio, Minas Gerais State, Brazil. It was tested four genotypes of C. arabica as grafts the varieties Catuaí Vermelho IAC 15 and Oeiras MG 6851 and the progenies H 419-10-3-1-5, H 514- 5-5-3 and three genotypes of C. canephora as rootstocks: Apoatã LC 2258, Conillon Muriaé-1 and recombination among clones of the variety Robustão Capixaba (EMCAPA 8141) and one genotype of C. arabica L.: Mundo Novo IAC 376-4. As a control it was wed non-grafted plants. Based on the results it could be concluded that plant development may was affected by grafting when non-grafted plants and graft/ rootstock combinations are compared. The grafting combinations Catuaí 15/Conilon, Oeiras/Apoatã, Oeiras/EMCAPA and H419/EMCAPA of 6 year, promoted increase in coffee yield, when compared to the respective non-grafted plant.

Marcadores moleculares AFLP, RAPD e SSR foram usados para estudo da diversidade e estrutura genética do germoplasma de Híbrido de Timor. As análises de coordenadas principais, de agrupamento UPGMA baseado na dissimilaridade genética de Jaccard, de agrupamento baseado no modelo Bayesiano, a percentagem de locos polimórficos, o índice de Shannon e a diversidade genética de Nei foram utilizadas para acessar a diversidade genética. As análises demonstraram alta diversidade genética entre os acessos de Híbrido de Timor. A análise de agrupamento UPGMA e o modelo Bayesiano permitiram a alocação dos acessos em três grupos. A estrutura genética dos acessos de Híbrido de Timor foi descrita. A manutenção e manuseio da variabilidade do germoplasma de Híbrido de Timor e seu potencial uso nos programas de melhoramento de cafeeiro foram discutidos.

AFLP, RAPD and SSR molecular markers were used to study the genetic diversity and genetic structure of the Híbrido de Timor germplasm. The principal coordinate analysis, UPGMA cluster analysis based on genetic dissimilarity of Jaccard, Bayesian model-based cluster analysis, percentage of polymorphic loci, Shannon's information index and Nei gene diversity were employed to assess the genetic diversity. The analyses demonstrated a high genetic diversity among Híbrido de Timor accessions. UPGMA and Bayesian cluster analyses grouped the accessions into three clusters. The genetic structure of Híbrido de Timor is reported. The management of Híbrido de Timor germplasm variability and its potential use in breeding programs are discussed.

Sequences potentially associated with coffee resistance to diseases were identified by in silico analyses using the database of the Brazilian Coffee Genome Project (BCGP). Keywords corresponding to plant resistance mechanisms to pathogens identified in the literature were used as baits for data mining. Expressed sequence tags (ESTs) related to each of these keywords were identified with tools available in the BCGP bioinformatics platform. A total of 11,300 ESTs were mined. These ESTs were clustered and formed 979 EST-contigs with similarities to chitinases, kinases, cytochrome P450 and nucleotide binding site-leucine rich repeat (NBS-LRR) proteins, as well as with proteins related to disease resistance, pathogenesis, hypersensitivity response (HR) and plant defense responses to diseases. The 140 EST-contigs identified through the keyword NBS-LRR were classified according to function. This classification allowed association of the predicted products of EST-contigs with biological processes, including host defense and apoptosis, and with molecular functions such as nucleotide binding and signal transducer activity. Fisher's exact test was used to examine the significance of differences in contig expression between libraries representing the responses to biotic stress challenges and other libraries from the BCGP. This analysis revealed seven contigs highly similar to catalase, chitinase, protein with a BURP domain and unknown proteins. The involvement of these coffee proteins in plant responses to disease is discussed.

No estudo da diversidade genética entre e dentro de populações de café, foram usados marcadores EST-SSR, visando avaliar seu potencial para identificar cultivares comerciais e assistir programas de melhoramento. Os 17 marcadores utilizados foram desenvolvidos a partir das seqüências ESTs do Projeto Brasileiro do Genoma Café. Em todos os marcadores observou-se polimorfismo entre os genótipos avaliados, com um número médio de 5,1 alelos por primer. Os maiores polimorfismos foram constatados dentro de C. canephora (88,2%) e em variedades resistentes à ferrugem (35,3%). Dos marcadores analisados, 29,4% distinguiram C. arabica dos Híbridos de Timor (HDT), sendo possível identificar os mais próximos e os mais distantes de C. arabica . A análise dos genótipos agrupados por população revelou diversidade genética de 64% entre populações e 36% dentro delas, com um índice de diferenciação de 0,637. Em seis marcadores distinguiram-se quatro variedades resistentes à ferrugem, constando seu potencial para fingerprint. Esses resultados demonstram a utilidade dos EST-SSR para orientações dos cruzamentos e estudos de diversidade, introgressão e mapeamento genético.

EST-SSR markers were used to investigate the genetic diversity among and within coffee populations, to explore the possibility of their use for fingerprinting of cultivars and to assist breeding programs. Seventeen markers, developed from ESTs (Expressed Sequence Tags) from the Brazilian Coffee Genome Project, were used. All markers showed polymorphism among the genotypes assessed. The average number of allele per primer was 5.1. The highest polymorphisms were found within C. canephora (88.2%) and rust-resistant varieties (35.3%). About 29.4% of the markers differentiated C. arabica from Híbrido de Timor; it was also possible to identify those closest and farthest from C. arabica . The analysis of population-grouped genotypes revealed a 64.0% genetic diversity among and a 36.0% genetic diversity within populations. The differentiation index was 0.637. Six markers distinguished four rust-resistance varieties, showing their fingerprinting potential. These results demonstrate the usefulness of EST-SSR markers for cross orientation, in diversity and introgression studies, and in genetic mapping.

O estudo da eficiência nutricional de plantas de cafeeiro (Coffea. arabica) enxertadas visou conhecer preliminarmente os potenciais de clones de Conilon (C. canephora) como porta-enxertos quanto à absorção e utilização de N, P e S. O experimento foi realizado no viveiro do setor de cafeicultura do Departamento de Fitopatologia da Universidade Federal de Viçosa, utilizando vasos de 20 litros em ambiente aberto. Foram empregados como porta-enxerto cinco progênies famílias de meio-irmãos de clones elites de C. canephora Pierre cv. Conilon do programa de melhoramento de cafeeiros robusta do INCAPER: 'ES 21', 'ES 36', 'ES 26', 'ES 23' e 'ES 38'. Utilizaram-se como enxertos as cultivares Catuaí Vermelho IAC 15 e Oeiras MG 6851 e as linhagens H 419-10-3-4-4 e H 514-5-5-3 de C. arabica. O delineamento experimental foi inteiramente casualizado, com 24 tratamentos e 3 repetições, sendo quatro pés-francos e 20 combinações de enxertia. No cultivo em vasos, a cultivar Catuaí Vermelho IAC 15 quando combinada com os porta-enxertos ES 26 e ES 23 apresentou maior produção de matéria seca e utilização de N e P quando comparada com o pé-franco. Na maioria das vezes as plantas enxertadas cultivadas em vaso, tiveram desempenho igual ou inferior às plantas controles ( pé-franco) quanto à eficiência nutricional e produção de matéria seca.

Studies of nutritional efficiency coffee (Coffea arabica) grafted plants were performed in order to verify the potential of Conilon (C. canephora) clones as rootstocks considering the absorption and use of N, P and S. The experiment was conducted in the coffee plant nursery of the Plant Pathology Department of the Federal University of Viçosa, Minas Gerais State, Brazil, in an open environment using 20 L pots. Five half-sibling elite clones of C. canephora Pierre cv. Conilon ('ES 21', 'ES 36', 'ES 26', 'ES 23' and 'ES 38') obtained from the INCAPER coffee breeding program were used as rootstocks. The cultivars Catuaí Vermelho IAC 15 and Oeiras MG 6851 and the progenies H 419-10-3-4-4 and H 514-5-5-3 of C. Arabica were used as grafts. The experimental design was completely randomized containing 24 treatments and 3 replicates with four control plants and 20 grafting combinations. Cultivating in pots, the cultivar Catuaí Vermelho IAC 15 combined with the rootstocks ES 26 and ES 23 presented higher production of dryer matter and use of N and P compared with the control. In general, grafted plants cultivated in pots showed similar or inferior performance in relation to the control varieties, regarding nutritional efficiency and dry matter production.

O estudo da eficiência nutricional de plantas enxertadas de cafeeiro é importante para a seleção de combinações enxerto/porta-enxerto visando desenvolvimento e produção máximos. O presente trabalho teve como objetivo avaliar as diferenças genéticas na eficiência de absorção, no transporte e na utilização de Potássio, Cálcio e Magnésio em mudas enxertadas de cafeeiro. O plantio foi realizado em vasos de 20L contendo como substrato terra, areia e esterco na proporção de 3:1:1, em que as plantas permaneceram por 18 meses até a coleta do experimento. Utilizaram-se como enxertos quatro genótipos de Coffea. arabica L.: as variedades Catuaí Vermelho IAC 15 e Oeiras MG 6851 e os híbridos H419-10-3-4-4 e H514-5-5-3 do programa de melhoramento da EPAMIG/UFV. Como porta-enxerto, foram empregados cinco progênies famílias de meios-irmãos de clones de Coffea canephora Pierre cv. Conilon: "ES 21", "ES 36", "ES 26", "ES 23" e "ES 38" do programa de melhoramento de café robusta do INCAPER. Houve variação da eficiência nutricional de K, Ca e Mg das plantas de cafeeiro em função da combinação enxerto/porta-enxerto. Na maioria das vezes, as plantas enxertadas tiveram desempenho inferior ao do pé-franco quanto à eficiência de absorção, translocação e utilização do K, Ca e Mg, bem como na produção de matéria seca. As combinações da variedade Catuaí Vermelho IAC 15 com os porta-enxertos ES 26 e ES 23 foram eficientes quanto à utilização de Mg e à produção de matéria seca. A baixa eficiência de absorção de K e Mg das combinações de enxertia com a cultivar Oeiras MG 6851 podem ter contribuído para a redução de produção de matéria seca total das mesmas.

Studies on the nutritional efficiency of grafted coffee trees are important for the selection of the rootstocks/grafts combinations that aim at for a good development and maximum yield. This study aimed to evaluate the genetic differences in the efficiency of K, Ca and Mg uptake, transport and use in grafted coffee seedlings. Trees were planted in 20-L pots containing soil, sand and manure (3:1:1) to grow for 18 months, until harvest. As grafts, four genotypes of Coffea arabica L were used: varieties Catuaí Vermelho IAC 15 and Oeiras MG 6851 and hybrids H419-10-3-4-4 and H514-5-5-3, of the breeding program of EPAMIG/UFV. As rootstocks, five half-sib progenies of Coffea canephora Pierre cv. Conilon clones were used: 'ES 21', 'ES 36', 'ES 26', 'ES 23' and 'ES 38', of the robust coffee breeding program of INCAPER. The nutritional efficiency of the coffee trees regarding K, Ca and Mg varied with the graft/ rootstock combination. The performance of the grafted coffee plants was inferior to the control varieties, with regard to the nutritional efficiency and dry matter yield. Catuaí Vermelho IAC 15 combined with the rootstocks ES 26 and ES 23 was highly effective regarding Mg utilization and dry matter yield. The dry weight reduction in the cv. Oeiras MG 6851 combinations may be explained by the low potassium and magnesium uptake efficiency.