Biblioteca do Café
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Item Coffee seed physiology(Brazilian Journal of Plant Physiology, 2006-06) Eira, Mirian T. S.; Silva, E. A. Amaral da; Castro, Renato D. De; Dussert, Stéphane; Walters, Christina; Bewley, J. Derek; Hilhorst, Henk W. M.Considerable advances in our understanding of coffee seed physiology have been made in recent years. However, despite intense research efforts, there are many aspects that remain unclear. This paper gives an overview of the current understanding of the more important features concerning coffee seed physiology, and provides information on recent findings on seed development, germination, storage and longevity.Item Aspects of nitrogen metabolism in coffee plants(Brazilian Journal of Plant Physiology, 2006-06) Carelli, Maria Luiza Carvalho; Fahl, Joel Irineu; Ramalho, José D. CochichoCoffee plants are highly N-demanding plants. Despite the importance of N nutrition for the development, acclimation and yield of coffee plants, there are few reports concerning N metabolism in this species. In this review, our intention is to summarize the information available in the literature and to point out the influence of environmental conditions on N assimilation, as well as comment and discuss some apparently contradictory results and raise and enlighten queries about N assimilation in coffee plants.Item Cytogenetics of coffee(Brazilian Journal of Plant Physiology, 2006-06) Pinto-Maglio, Cecília A. F.The genus Coffea L. has around 100 native species distributed in tropical and subtropical areas in Africa, and the most important economic species are C. arabica and C. canephora. C. arabica is exceptional in the genus since it is the only species so far analyzed which is self-compatible, and a natural polyploid with 2n=4x=44 chromosomes; it is considered to be a segmental allopolyploid because it presents a disomic inheritance and a regular meiotic behavior. All other species in the genus are self-incompatible diploids with 2n=2x=22. Cytogenetic studies in Coffea, undertaken since 1912, have followed various phases: initial studies were limited only to establishing chromosome counts. Subsequent studies characterized the karyotypes of various species using conventional cytological techniques. As the somatic metaphase chromosomes of coffee are very small (1 - 3 µm) and morphologically symmetrical, these studies resulted in uniform karyotypes that show almost no differences among species. Since genetic improvement of coffee trees has progressed mainly by means of interspecific hybridizations involving wild species, analyses of microsporogenesis in species and hybrids were needed to establish their genetic affinity and relationships. The first successful attempts to differentiate coffee chromosomes longitudinally were made by mapping pachytene chromomeric patterns and by C and NOR banding techniques. From 1998 onwards, the use of banding techniques with the fluorochromes DAPI and CMA3, and also the cytomolecular technique FISH using rDNA probes, has increased the longitudinal differentiation of coffee chromosomes. The use of the GISH technique with total genomic DNA has revealed the parental species that originated C. arabica species.Item Selection for durable resistance to leaf rust using test-crosses on IAPAR-59 and Tupi IAC 1669-33 cultivars of Coffea arabica(Instituto de Tecnologia do Paraná - Tecpar, 2007-07) Sera, Gustavo Hiroshi; Sera, Tumoru; Ito, Dhalton Shiguer; Azevedo, José Alves de; Mata, João Siqueira da; Doi, Deisy Saori; Ribeiro Filho, ClaudionorThe aim of this study was to identify plants of the IAPAR-59 and Tupi IAC 1669-33 coffee cultivars with less defeated resistance genes by the rust races present at IAPAR (Londrina, Paraná State, Brazil) using test-crosses. Eighteen test-crosses derived from hybridizations between 'IAPAR-59' or 'Tupi IAC 1669-33' with susceptible coffee to the rust disease were evaluated. Six hybrids were used as susceptible standards originated from hybridizations between two susceptible coffee plants. Many parental plants of the 'IAPAR-59' and 'Tupi IAC 1669-33' presented more defeated resistance genes against rust races present at IAPAR than others of these cultivars or the genes were in heterozygous, because of segregant susceptible plants observed in some test-crosses. The test-crosses were very efficient to identify plants with less defeated resistance genes to the H. vastatrix. Coffee plants considered resistants would must be made test-crosses to verify which plants presented less and/or more defeated genes in homozygous.Item Partial resistance to fruit necrosis associated to Colletotrichum spp. among arabic coffee genotypes(Instituto de Tecnologia do Paraná - Tecpar, 2007-05) Sera, Gustavo Hiroshi; Sera, Tumoru; Ito, Dhalton Shiguer; Azevedo, José Alves de; Ribeiro Filho, Claudionor; Mata, João Siqueira daThe aim of this study was to evaluate the resistance to fruit necrosis associated to Colletotrichum spp. in Coffea arabica L.. Twenty-two arabic coffee genotypes were performed in a randomized block design, with three replications and ten plants per plot. They were evaluated for the variables fruit necrosis, luminosity index inside of the plant canopy and fruits per productive nodes of the plants. There was genetic variability for the resistance to fruit necrosis. Different partial resistance levels, varying from highly susceptible (score = 3.89) to moderately resistant (score = 1.77) were observed. The genotypes that presented moderate resistance were the cultivars IPR-100, IPR-103, IPR-105 and IPR-108 and the coffee selection IAPAR-00023.Item Coffee carbohydrates(Brazilian Journal of Plant Physiology, 2006-06-14) Redgwell, Robert; Fischer, MonicaThis review summarises recent advances in the chemistry, physiology and molecular properties of coffee carbohydrates with a particular focus on the cell wall polysaccharides. The results of detailed chemical studies have demonstrated novel structural features of both the galactomannans and the arabinogalactan polysaccharides of the green and roasted coffee bean. For the first time immunological probes based on monoclonal antibodies for specific polysaccharide epitopes were used to reveal the patterns of distribution of the galactomannans, arabinogalactans and pectic polysaccharides in the coffee bean cell wall. Finally, the results of physiological and molecular studies are presented which emphasise the growing awareness of the potential role the metabolic status of the green bean may play in final coffee beverage quality.Item Genetic transformation of coffee(Brazilian Journal of Plant Physiology, 2006-06-14) Ribas, Alessandra Ferreira; Pereira, Luiz Filipe Protasio; Vieira, Luiz Gonzaga E.In the last 15 years, considerable advances were made in coffee genetic transformation. Different research groups in the world have been able to transform coffee with genes for insect resistance, decaffeinated coffee, herbicide resistance and control of fruit maturation. Although the majority of the research is still limited to laboratory and greenhouse studies, initial field tests with transformed coffee are beginning to appear in the literature. In this review we provide an update on the state of coffee genetic transformation, presenting technical aspects related to tissue culture systems, strategies for selection and transformation with particle bombardment, as well as the use of Agrobacterium tumefaciens. We also discuss the potential applications of this technology, taking into consideration the benefits, the possible environmental risks, as well as market and consumer issues.Item Coffee biotechnology(Brazilian Journal of Plant Physiology, 2006-06-14) Santos-Briones, César De Los; Hernández-Sotomayor, S. M. TeresaIn the last three decades, interest has turned to in vitro cell culture in different areas of coffee research. In vitro techniques have been applied not only for coffee improvement through genetic transformation but also to study various aspects in coffee cells such as chemical (caffeine synthesis and the production of coffee aroma), physiological and more recently, biochemical aspects. The most important advances obtained to date on in vitro coffee techniques in fields like biochemistry, physiology, regeneration systems and genetic engineering, are presented and discussed.Item Cytology, biochemistry and molecular changes during coffee fruit development(Brazilian Journal of Plant Physiology, 2006-06-14) Castro, Renato D. De; Marraccini, PierreIn commercial coffee species (Coffea arabica and Coffea canephora), fruit development is a lengthy process, characterized by tissue changes and evolutions. For example, soon after fecundation and up to mid development, the fruit is mainly constituted of the pericarp and perisperm tissue. Thereafter, the perisperm gradually disappears and is progressively replaced by the endosperm (true seed). Initially present in a "liquid" state, the endosperm hardens as it ripens during the maturation phase, as a result of accumulation of storage proteins, sucrose and complex polysaccharides representing the main reserves of the seed. The last step of maturation is characterized by the dehydration of the endosperm and the color change of the pericarp. Important quantitative and qualitative changes accompany fruit growth, highlighting the importance of its study to better understand the final characteristics of coffee beans. Following a description of the coffee fruit tissues, this review presents some data concerning biochemical, enzymatic and gene expression variations observed during the coffee fruit development. The latter will also be analyzed in the light of recent data (electronic expression profiles) arising from the Brazilian Coffee Genome Project.Item Genetics of coffee quality(Brazilian Journal of Plant Physiology, 2006-06-14) Leroy, Thierry; Ribeyre, Fabienne; Bertrand, Benóit; Charmetant, Pierre; Dufour, Magali; Montagnon, Christophe; Marraccini, Pierre; Pot, DavidCoffee quality, in the present context of overproduction worldwide, has to be considered as a main selection criterion for coffee improvement. After a definition of quality, and an overview of the non genetic factors affecting its variation, this review focuses on the genetic factors involved in the control of coffee quality variation. Regarding the complexity of this trait, the different types of quality are first presented. Then, the great variation within and between coffee species is underlined, mainly for biochemical compounds related to quality (caffeine, sugars, chlorogenic acids, lipids). The ways for breeding quality traits for cultivated species, Coffea arabica and Coffea canephora are discussed, with specific challenges for each species. For C. arabica, maintaining a good quality in F1 intraspecific hybrids, introgressed lines from Timor hybrid, and grafted varieties are the main challenges. For C. canephora, the improvement is mainly based on intraspecific and interspecific hybrids, using the whole genetic variability available within this species. An improvement is obtained for bean size, with significant genetic gains in current breeding programmes. The content in biochemical compounds related to cup quality is another way to improve Robusta quality. Finally, ongoing programmes towards the understanding of the molecular determinism of coffee quality, particularly using coffee ESTs, are presented.