Scientia Agrícola

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Adição de Zn e absorção, translocação e utilização de Zn e P por cultivares de cafeeiro
(Escola Superior de Agricultura "Luiz de Queiroz", 2002-07) Reis Jr, Roberto dos Anjos; Martinez, Hermínia E. P.
A crescente exigência de nutrientes, especialmente micronutrientes, pelos cultivares de café vem exigindo uma melhor compreensão da dinâmica desses nutrientes no sistema solo-planta. Com o objetivo de avaliar o efeito de concentrações de Zn (0,4 ; 1,3 e 2,3 μmol Zn L -1 ) na solução nutritiva sobre o crescimento, produção de matéria seca, eficiência de absorção, translocação e utilização de Zn e P em dois cultivares de café (Coffea arabica cv. Catuaí e Coffea canephora cv. Conilon), foi realizado um experimento sob delineamento inteiramente casualizado com esquema fatorial 3 × 2 (três doses de Zn e dois cultivares) com três repetições. Plantas de café dos dois cultivares estudados foram cultivadas em casa de vegetação, com solução nutritiva completa por 50 dias, após os quais receberam solução nutritiva modificada com três doses de Zn. Aos 114 dias após a transferência para a solução nutritiva modificada, as plantas foram coletadas e separadas em folhas superiores, inferiores, caule e raízes. Foram avaliadas altura do caule, número de ramificações laterais, área foliar, produção de matéria seca e conteúdos de P e Zn nas diversas partes da planta, além das eficiências de absorção, translocação e utilização de P e Zn. A dose 2,3 μmol Zn L -1 proporcionou os maiores valores para as características de crescimento avaliadas, tanto para o cultivar Catuaí, quanto para Conilon. Os maiores conteúdos de Zn observados no Catuaí indicam que este é mais exigente em Zn que o Conilon na fase de mudas. O Conilon apresentou menores eficiências de absorção e translocação e maior eficiência de utilização de Zn, refletindo sua menor demanda por este nutriente. As concentrações de Zn empregadas neste experimento não promoveram interação Zn-P.
Agroforestry systems, nutrients in litter and microbial activity in soils cultivated with coffee at high altitude
(Escola Superior de Agricultura "Luiz de Queiroz", 2014-03) Notaro, Krystal de Alcantara; Medeiros, Erika Valente de; Duda, Gustavo Pereira; Silva, Aline Oliveira; Moura, Patrícia Maia de
Agroforestry systems are an alternative option for sustainable production manage- ment. These systems contain trees that absorb nutrients from deeper layers of the soil and leaf litter that help improve the soil quality of the rough terrain in high altitude areas, which are areas extremely susceptible to environmental degradation. The aim of this study was to characterize the stock and nutrients in litter, soil activity and the population of microorganisms in coffee (Cof- fea arabica L.) plantations under high altitude agroforestry systems in the semi-arid region of the state of Pernambuco, Brazil. Samples were collected from the surface litter together with soil samples taken at two depths (0-10 and 10-20 cm) from areas each subject to one of the follow- ing four treatments: agroforestry system (AS), native forest (NF), biodynamic system (BS) and coffee control (CT).The coffee plantation had been abandoned for nearly 15 years and, although there had been no management or harvesting, still contained productive coffee plants. The ac- cumulation of litter and mean nutrient content of the litter, the soil nutrient content, microbial biomass carbon, total carbon, total nitrogen, C/N ratio, basal respiration, microbial quotient, metabolic quotient and microbial populations (total bacteria, fluorescent bacteria group, total fungi and Trichoderma spp.) were all analyzed. The systems that were exposed to human inter- vention (AS and BS) differed in their chemical attributes and contained higher levels of nutrients when compared to NF and CT. BS for coffee production at high altitude can be used as a sustain- able alternative in the high altitude zones of the semi-arid region in Brazil, which is an area that is highly susceptible to environmental degradation.
Agronomic practices toward coffee sustainability. A review
(Escola Superior de Agricultura "Luiz de Queiroz", 2023-10-23) Martinez, Herminia Emilia Prieto; Andrade, Sara Adrián López de; Santos, Ricardo Henrique Silva; Baptistella, João Leonardo Corte; Mazzafera, Paulo
The coffee sector is estimated to have a retail market value in excess of USD 83 billion, and over 125 million jobs have been created in the global coffee chain. The coffee specialty market has recently increased significantly, generating opportunities to certify coffee beans produced by sustainable practices. This avoids practices potentially harmful to the environment. Agroforestry, organic farming, intercropping, and soil conservation strategies are examples of sustainable alternatives in the production of coffee. In this review, we focus on practices for the sustainable management of coffee plantations that can help farmers fight problems caused by global warming. More specifically, we address soil organic matter and microbiota, the use of Urochloa grass as intercrop in coffee plantations, shading systems (including agroforestry), and organic coffee production. We concluded that from the agronomic viewpoint, we already have production techniques that can replace traditional ones with significant advantages accruing to the quality of coffee orchard ecosystems. Nevertheless, we need scientific research efforts to deal with the existing gaps and the engagement of the whole coffee chain as a means of guaranteeing an adequate profit to those smallholders who adopt and maintain sustainable practice and are capable of bringing several positive changes to the coffee crop, including the use of microbia-based commercial products and new organic sources of nutrients to complement chemical fertilizers and improve coffee quality.
Avaliação da qualidade de frutos de café atacados por Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae)
(Escola Superior de Agricultura "Luiz de Queiroz", 1993-07) Cividanes, F.J.; Nakano, O.; Melo, M.
Foram usadas plantas de Coffea arabica L., variedade Catuaí Vermelho, localizadas no Campus da Escola Superior de Agricultura "Luiz de Queiroz" - USP, Piracicaba,SP, para avaliação dos danos que Ceratitis capitata (Wied., 1824) pode causar aos frutos do cafeeiro. Os resultados mostraram que o ataque de C. capitula não causou queda prematura dos frutos, mas aumentou a queda de cerejas e foram encontradas, fortes evidências, com base na atividade da enzima polifenol oxidase e lixiviação de potássio, que cerejas atacadas podem produzir bebida de café de qualidade inferior.
Bayesian sequential procedure to estimate the viability of seeds Coffea arabica L. in tetrazolium test
(Escola Superior de Agricultura "Luiz de Queiroz", 2019-05) Brighenti, Carla Regina Guimarães; Cirillo, Marcelo Ângelo; Costa, André Luís Alves; Rosa, Sttela Dellyzete Veiga Franco da; Guimarães, Renato Mendes
Tetrazolium tests use conventional sampling techniques in which a sample has a o Zootecnia, Av. Visconde do Rio Preto, s/n — 36301-360 — fixed size. These tests may be improved by sequential sampling, which does not work with fixed- s São João Del-Rei, MG — Brasil. size samples. When data obtained from an experiment are analyzed sequentially the analysis can OM 2Universidade Federal de Lavras -— Depto. de Estatística, C.P. be terminated when a particular decision has been made, and thus, there is no need to pre-es- "O 3037 - 37200-000 - Lavras, MG - Brasil. tablish the number of seeds to assess. Bayesian statistics can also help, if we have sufficient = Embrapa Café, PqEB, s/n - 70770-901 - Brasília, DF — knowledge about coffee production in the area to construct a prior distribution. Therefore, we Brasil. used the Bayesian sequential approach to estimate the percentage of viable coffee seeds sub- os “Universidade Federal de Lavras — Depto. de Agricultura. mitted to tetrazolium testing, and we incorporated priors with information from other analyses — *Corresponding author of crops from previous years. We used the Beta prior distribution and, using data obtained from Ss sample lots of Coffea arabica, determined its hyperparameters with a histogram and O'Hagan's O Edited by: Marcin Kozak methods. To estimate the lowest risk, we computed the Bayes risks, which provided us with a = basis for deciding whether or not we should continue the sampling process. The results confirm e Received April 13, 2017 that the Bayesian sequential estimation can indeed be used for the tetrazolium test: the average Fi; Accepted January 06, 2018 percentage of viability obtained with the conventional frequentist method was 88 %, whereas that v obtained with the Bayesian method with both priors was 89 %. However, the Bayesian method E required, on average, only 89 samples to reach this value while the traditional estimation method O needed as many as 200 samples.
Bioprospecting endophytic bacteria for biological control of coffee leaf rust
(Escola Superior de Agricultura "Luiz de Queiroz", 2006-01) Shiomi, Humberto Franco; Silva, Harllen Sandro Alves; Melo, Itamar Soares de; Nunes, Flávia Vieira; Bettiol, Wagner
Suppression of plant diseases due to the action of endophytic microorganisms has been demonstrated in several pathosystems. Experiments under controlled conditions involving endophytic bacteria isolated from leaves and branches of Coffea arabica L and Coffea robusta L were conducted with the objective of evaluating the inhibition of germination of Hemileia vastatrix Berk. & Br., race II, urediniospores and the control of coffee leaf rust development in tests with leaf discs, detached leaves, and on potted seedling of cv. Mundo Novo. The endophytic bacterial isolates tested proved to be effective in inhibiting urediniospore germination and/or rust development, with values above 50%, although the results obtained in urediniospore germination tests were inferior to the treatment with fungicide propiconazole. Endophytic isolates TG4-Ia, TF2-IIc, TF9-Ia, TG11-IIa, and TF7-IIa, demonstrated better coffee leaf rust control in leaf discs, detached leaves, and coffee plant tests. The endophytic isolates TG4-Ia and TF9-Ia were identified as Bacillus lentimorbus Dutky and Bacillus cereus Frank. & Frank., respectively. Some endophytic bacterial isolates were effective in controlling the coffee leaf rust, although some increased the severity of the disease. Even though a relatively small number of endophytic bacteria were tested, promising results were obtained regarding the efficiency of coffee leaf rust biocontrol. These selected agents appears to be an alternative for future replacement of chemical fungicide.
Brachiaria decumbens supresses the initial growth of Coffea arabica
(Escola Superior de Agricultura "Luiz de Queiroz", 2004-11) Dias, Guilherme Faus da Silva; Alves, Pedro Luís da Costa Aguiar; Dias, Tomás Carneiro de Souza
Brachiaria decumbens vem se tornando uma das plantas daninhas mais freqüentes na infestação de cafezais em formação, pois além de sua elevada agressividade e dificuldade de controle, está ocorrendo expansão das áreas cafeeiras para locais anteriormente ocupados por pastagens. Objetivou-se neste trabalho avaliar os efeitos desta planta daninha, em densidades crescentes, sobre o desenvolvimento inicial de mudas de café (Coffea arabica L. cv. Catuaí Amarelo). O experimento foi conduzido em condições semi-controladas, sem limitação de água. Uma muda de café foi transplantada em caixa de amianto com capacidade para 70 L, preenchida com terra coletada da camada arável de um Latossolo Vermelho. Os tratamentos constaram de diferentes densidades de transplante de capim-braquiária, a saber: 0, 4, 8, 12, 16, 20, 24, 36, 48 e 60 plantas m - 2. O ensaio foi conduzido por um período experimental de 120 dias após o plantio (DAP). Todas as características analisadas foram afetadas negativamente pela interferência da planta daninha, mas as que se mostraram mais sensíveis a essa interferência foram à área foliar e a biomassa seca das folhas. Houve redução de 41,8% na área foliar do cafeeiro quando conviveu com o capim-braquiária a partir da densidade de 8 plantas m - 2, chegando a 68,7% na densidade de 60 plantas m -2 . Também a partir da densidade de 8 plantas m -2 , a redução na biomassa seca das folhas em relação à testemunha foi de 41,4% e na densidade de 60 plantas m - 2 chegou a 72,8%. Brachiaria decumbens, a partir da densidade de 8 plantas m - 2, interfere negativamente sobre as mudas de café até os 120 DAP.
Clonal Arabica coffee resistant to Meloidogyne paranaensis and damage threshold on plants development
(Escola Superior de Agricultura "Luiz de Queiroz", 2019-05) Fatobene, Bárbhara Joana dos Reis; Gonçalves, Wallace; Oliveira, Claudio Marcelo Gonçalves; Guerreiro Filho, Oliveiro
Plants of Coffea arabica Icatu IAC 925 germplasm show resistance to Meloidogyne paranaensis under field conditions, but with variable rates of segregation. One mother plant, IAC 3, of Icatu IAC 925 was evaluated under controlled conditions through the reaction of its clones, obtained by somatic embryogenesis. Reproduction of nematodes in clones were compared with an open-pollinated progeny from the same mother plant, C. arabica cultivar Mundo Novo IAC 515-20, susceptible to nematodes, and Clone IAC 1, also susceptible and obtained by somatic embryogenesis. Open-pollinated progeny showed segregation to resistance and was classified as susceptible according to the reproduction factor. The average number of nematodes (eggs and J2) per gram of roots in clones was eight fold lower than that of open-pollinated progeny, and 51 fold lower than Mundo Novo IAC 515-20. Based on Seinhorst model, IAC 3 clone showed a tolerance limit of 7.7 nematodes per cm3 of soil, while in Mundo Novo the tolerance limit was 3.9 nematodes per cm3 of soil. These results revealed that clonal Arabica coffee nematode- resistant trees represent an alternative to the time consuming and expensive process inherent to conventional breeding strategies.
Coffee crops adaptation to climate change in agroforestry systems with rubber trees in southern Brazil
(Escola Superior de Agricultura "Luiz de Queiroz", 2022-04-13) Zaro, Geovanna Cristina; Caramori, Paulo Henrique; Wrege, Marcos Silveira; Caldana, Nathan Felipe da Silva; Virgens Filho, Jorim Sousa das; Morais, Heverly; Yada Junior, George Mitsuo; Caramori, Daniel Campos
Adaptation to climate change is a strategy for crops to cope with the scenario of rising temperatures worldwide. In the case of Coffea arabica L., the use of agroforestry systems (AFS) with woody species is a promising practice to reduce excessive heat during the day. This study aimed to 1) evaluate air temperature changes that occur in an AFS of coffee and double alleys of rubber trees (Hevea brasiliensis Müell. Arg.) and 2) carry out an analysis of future warming scenarios by comparing the cultivation of Arabic coffee in full sun and in an AFS of double alleys of rubber trees. The microclimatic variables were measured between two rows of coffee trees at 1.0 m of height from June 2016 to June 2018. The results indicate that the AFS with double alleys of rubber trees spaced 16 m apart had an average temperature reduction from 1.4 to 2.5 °C from 10h00 to 16h00. The study also simulated temperature increases of 1.7, 2.6, 3.1, and 4.8 °C from 2018 to 2099, according to scenarios predicted by the Intergovernmental Panel on Climate Change (IPCC), and the impact in coffee production in Paraná State, Brazil. Using the climatic generator PGECLIMA_R, simulations suggest a progressive reduction of traditional areas suitable for open-grown coffee in the state. Production conditions can be maintained through the AFS, since the systems attenuate mean temperatures by 1-2 °C. We conclude that the AFS of coffee and rubber trees contribute to coffee crop adaptations to a future warmer environment.
Comparison between climatological and field water balances for a coffee crop
(Escola Superior de Agricultura "Luiz de Queiroz", 2007-05) Bruno, Isabeli Pereira; Silva, Adriana Lúcia da; Reichardt, Klaus; Dourado-Neto, Durval; Bacchi, Osny Oliveira Santos; Volpe, Clóvis Alberto
The use of climatological water balances in substitution to complete water balances directly measured in the field allows a more practical crop management, since the climatological water balances are based on data monitored as a routine. This study makes a comparison between these methods in terms of estimatives of evapotranspiration, soil water storage, soil available water, runoff losses, and drainage below root zone, during a two year period, taking as an example a coffee crop of the variety Catuaí, three to five years old. Climatological water balances based on the estimation of the evapotranspiration through the methods of Thornthwaite and Penman-Monteith, can reasonably substitute field measured balances, however underestimating the above mentioned variables.
Compatibility between the entomopathogenic fungus beauveria bassiana and insecticides used in coffee plantations
(Escola Superior de Agricultura "Luiz de Queiroz", 2003-10) Oliveira, Carolina Natali de; Neves, Pedro Manuel Oliveira Janeiro; Kawazoe, Lídio Sueki
Microbial control in integrated pest management (IPM) programs of coffee plantations is an important factor for the reduction of pest population densities. The use of selective pesticides can be associated with entomopathogens, increasing the efficiency of the control and reducing the use of required insecticides. The in vitro fungitoxic effect of insecticide formulations of Thiamethoxam, Cyfluthrin, Deltamethrin, Alpha- Cypermethrin, Triazophos, Chlorpyrifos, Fenpropathrin and Endosulfan and Beauveria bassiana (CG 425 strain) was evaluated at three concentrations (FR = average field recommendation; 0.5 × FR and 2 × FR). Effects of these products on conidia germination, vegetative growth and sporulation were compared. Only five insecticides, at the FR concentration, promoted conidia viability higher than 60%. Viability should be considered the most important factor to be evaluated since it is the first step of the infection process. The insecticide formulations of Alpha-Cypermethrin, Thiamethoxam and Cyfluthrin caused the lower inhibition level on conidia germination at the two lower concentrations, with no difference in relation to the control. With respect to vegetative growth analysis, Thiamethoxam at the two lower concentrations was not found to cause radial growth inhibition. Thiamethoxam caused the smallest inhibition level with regard to conidia production. The use of Alpha-Cypermethrin and Thiamethoxam formulations in coffee IPM programs for a B. bassiana inoculum conservation strategy are recommended, since these products were compatible with the entomopathogenic fungus Beauveria bassiana (CG 425), an important natural control agent of the coffee berry borer, Hypothenemus hampei.
Definition of management zones in coffee production fields based on apparent soil electrical conductivity
(Escola Superior de Agricultura "Luiz de Queiroz", 2012-05) Valente, Domingos Sárvio Magalhães; Queiroz, Daniel Marçal de; Pinto, Francisco de Assis de Carvalho; Santos, Nerilson Terra; Santos, Fábio Lúcio
Fertilizer application at variable rates requires dense sampling to determine the resulting field spatial variability. Defining management zones is a technique that facilitates the variable-rate application of agricultural inputs. The apparent electrical conductivity of the soil is an important factor in explaining the variability of soil physical-chemical properties. Thus, the objective of this study was to define management zones for coffee (Coffea Arabica L.) production fields based on spatial variability of the apparent electrical conductivity of the soil. The resistiv- ity method was used to measure the apparent soil electrical conductivity. Soil samples were collected to measure the chemical and physical soil properties. The maps of spatial variability were generated using ordinary kriging method. The fuzzy k-means algorithm was used to delimit the management zones. To analyze the agreement between the management zones and the soil properties, the kappa coefficients were calculated. The best results were obtained for the management zones defined using the apparent electrical conductivity of the soil and the digital elevation model. In this case, the kappa coefficient was 0.45 for potassium, which is an element that is associated with quality coffee. The other variable that had a high kappa coefficient was remaining phosphorous; the coefficient obtained was 0.49. The remaining phosphorus is an important parameter for determining which fertilizers and soil types to study.
Degradation of caffeine by microorganisms and potential use of decaffeinated coffee husk and pulp in animal feeding
(Escola Superior de Agricultura "Luiz de Queiroz", 2002-10) Mazzafera, Paulo
Coffee husk and coffee pulp are coffee processing by-products. Coffee husk is obtained when harvested coffee is processed by the dry method, and coffee pulp is produced by the wet method. In Brazil, coffee is usually processed by the dry method, therefore an expressive amount of husk is obtained every year. Some of the husk is used as organic fertilizer but, other applications are very limited, mainly because it is a bulky product. The presence of tannins and caffeine diminish acceptability and palatability of husk by animals. This review discuss degradation of caffeine by microorganisms, with special attention to bacterial, biological decaffeination of coffee husk and pulp and its subsequent use on animal feeding. The known biochemical routes of caffeine degradation by microorganisms are initially discussed; problems concerning physiological effects in animals, focusing on the limitations imposed by caffeine as an antiphysiological component are raised; the use of microorganisms to decaffeinate coffee husk and pulp is discussed. The discussions offer a view on decreasing caffeine content of coffee husk and pulp, which would allow the use of larger amounts of these products in animal feeding, partially replacing traditional components such as cereal grains.
Detection of coffee fruits on tree branches using computer vision
(Escola Superior de Agricultura "Luiz de Queiroz", 2022-09-12) Bazame, Helizani Couto; Molin, José Paulo; Althoff, Daniel; Martello, Maurício
Coffee farmers do not have efficient tools to have sufficient and reliable information on the maturation stage of coffee fruits before harvest. In this study, we propose a computer vision system to detect and classify the Coffea arabica (L.) on tree branches in three classes: unripe (green), ripe (cherry), and overripe (dry). Based on deep learning algorithms, the computer vision model YOLO (You Only Look Once), was trained on 387 images taken from coffee branches using a smartphone. The YOLOv3 and YOLOv4, and their smaller versions (tiny), were assessed for fruit detection. The YOLOv4 and YOLOv4-tiny showed better performance when compared to YOLOv3, especially when smaller network sizes are considered. The mean average precision (mAP) for a network size of 800 × 800 pixels was equal to 81 %, 79 %, 78 %, and 77 % for YOLOv4, YOLOv4-tiny, YOLOv3, and YOLOv3-tiny, respectively. Despite the similar performance, the YOLOv4 feature extractor was more robust when images had greater object densities and for the detection of unripe fruits, which are generally more difficult to detect due to the color similarity to leaves in the background, partial occlusion by leaves and fruits, and lighting effects. This study shows the potential of computer vision systems based on deep learning to guide the decision-making of coffee farmers in more objective ways.
Dispersal capacity of fruit fly parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae) in irrigated coffee plantations
(Escola Superior de Agricultura "Luiz de Queiroz", 2016-05) Camargos, Maria Gisely; Alvarenga, Clarice Diniz; Giustolin, Teresinha Augusta; Paranhos, Beatriz Aguiar Jordão; Oliveira, Patrícia Cristina do Carmo; Rabelo, Marcelo Mendes
Diachasmimorpha longicaudata is an Old World parasitoid of tephritid fruit flies that was widely introduced in the Americas to control pest species such as the Mediterranean fruit fly Ceratitis capitata. Augmentative releases in irrigated coffee plantations in semiarid regions of Brazil are under consideration and dispersal capacity of D. longicaudata in this habitat are important to develop release strategies. Approximately 2,000 individuals of D. longicaudata (5 to 7 days old) were released in the center of a fruiting coffee plantation every two weeks from Dec. 2009 to Apr. 2010. Dispersal from the central release point was monitored to the north, south, east, west, northeast, northwest, southeast and southwest at 11 distances, beginning at 4.6 m and ending at 90 m from the release point. At each point, a parasitism unit (approximately 120 larvae of C. capitata in the 3rd instar wrapped in voile fabric) and 10 coffee beans were collected. The average dispersion distance and dispersion area were estimated by the model proposed by Dobzhansky and Wright (1943). The average dispersion distances were 27.06 m (as estimated by fruit collection) and 33.11 m (as estimated by oviposition traps). The average dispersion areas were 1,315.25 m2 and 1,752.45 m2 originating from the collection of beans and parasit- ism units, respectively. Cohorts of 2,000 adult D. longicaudata released at six points ha−1 are estimated to result in sufficient colonization to exert significant control of Ceratitis capitata.
Estudo da influência da época de coleta dos ramos, no enraizamento de estacas caulinares de café (Coffea arabica L. CV "Mundo Novo")
(Escola Superior de Agricultura "Luiz de Queiroz", 1992-01) Ono, E.O.; Rodrigues, J.D.; Pinho, S.Z. de
Na propagação vegetativa através de estacas caulinares, a época de retirada dos ramos, que serão utilizados na confecção das estacas, tem grande influência sobre seu enraizamento. Outro fator de grande relevância é o tratamento auxínico, realizado nas estacas, que promove a formação de raízes. O presente trabalho teve como objetivo, verificar a ação das auxinas e do boro e a influência da época de coleta dos ramos de cafeeiro, sobre o enraizamento de ramos ortotrópicos semi-lenhosos de café (Coffea arabica L. cv "Mundo Novo"). Para tal, o experimento foi montado mensalmente, realizando-se as seguintes medidas , mediante coleta das estacas, após 90 dias do plantio: número de estacas enraizadas e número total de raízes formadas. À partir dos resultados obtidos, concluiu-se que, a melhor época de coleta dos ramos é na estação chuvosa. Além disso, tratamentos com NAA à 200 ppm mais boro, também promovem uma alta porcentagem de enraizamento. Descritores: estacas, café, enraizamento, auxinas, boro.
Extração e dosagem da atividade da polifenoloxidase do café
(Escola Superior de Agricultura "Luiz de Queiroz", 2002-10) Mazzafera, Paulo; Gonçalves, Kátia Viviane; Shimizu, Milton Massao
A atividade de polifenoloxidase (PFO) tem sido usada como indicadora da qualidade de bebida de café. Foram feitas comparações entre o método tradicionalmente usado para extração de polifenoloxidase de café e outro, onde impediu-se a oxidação de fenóis durante a extração, com posterior eliminação por filtração em coluna de exclusão. Um método intermediário entre os dois também foi testado. As medições de atividade foram feitas por espectrofotometria e por consumo de O 2 . Os métodos tradicionais de extração e dosagem da atividade de PFO sofrem forte interferência de fenóis presentes no extrato, não permitindo reprodução dos dados publicados na literatura. Por espectrofotometria foi possível diferenciação apenas entre café de bebida Mole de cafés de bebida Dura e Rio, mas não entre as duas últimas. Café de melhor qualidade, bebida Mole, apresentou maior atividade de PFO. Extração de PFO na presença de antioxidantes e complexadores de fenóis, seguida pela eliminação dos mesmos por cromatografia de exclusão é essencial para uma avaliação correta. Entretanto, usando este procedimento e consumo de O 2 , a atividade de PFO também não diferenciou os três cafés testados, exceto o Mole dos dois outros. No lugar de DOPA (3,4 – dihidroxifenilalanina), usado comumente nas dosagens por espectrofotometria, sugere-se o emprego de ácido clorogênico (ácido 5-cafeoilquínico).
Genetic characterization of Xylella fastidiosa isolated from citrus and coffee plants
(Escola Superior de Agricultura "Luiz de Queiroz", 2007-09) Miranda, Vicente Savonitti; Farias, Paulo Roberto Silva; Roberto, Sérgio Rufo; Lacava, Pedro Magalhães
The Citrus Variegated Chlorosis and the Coffee Leaf Scorch are some of the many destructive diseases caused by Xylella fastidiosa, a gram-negative bacterium limited to the xylem of affected plants. As its genetic characterization is still not well established, different isolates of X. fastidiosa from citrus and coffee were evaluated through RAPD (Random Amplified Polymorphic DNA) technique to characterize and classify these isolates based on similarity coefficients. Sixteen isolates of X. fastidiosa were used on this trial, obtained from citrus, coffee and almond. The genetic polymorphism evaluation was performed using six arbitrary 10-base primer pairs. It was possible to establish a dendogram in which the isolates were classified into five groups (A, B, C, D and E). A prevalence of citrus isolates in groups A and D was observed. In groups B and C, there was a prevalence of coffee isolates meanwhile the group D consisted of the almond isolate, solely.
Genetic diversity of cultivated Coffea arabica inbred lines assessed by RAPD, AFLP and SSR marker systems
(Escola Superior de Agricultura "Luiz de Queiroz", 2005-07) Maluf, Mirian Perez; Silvestrini, Milene; Ruggiero, Luciana Machado de Campos; Guerreiro Filho, Oliveiro; Colombo, Carlos Augusto
One of the greatest problems in Coffea arabica breeding is identifying precisely any inbred line, based only on botanical and agronomical descriptors, because of the reduced genetic variability of the species, close pedigree origin, which results in small phenotypic variation. Recently, molecular markers have been used for plant germplasm characterization and identification in several commercial species. This work evaluates the reliability of three marker systems: RAPD, AFLP and SSR, to characterize the genetic variability of commercially-used Coffea inbred lines developed by the Instituto Agronômico (IAC), and their potential for cultivar identification. All methods identified polymorphisms among the cultivars. The genetic diversity recognized by the methods is very similar, although is very narrow. RAPD and SSR marker systems grouped more efficiently the evaluated cultivars according to parental origin. None of the methods allowed inbred line identification. Therefore for varietal protection, it would be necessary using a combination of botanical, agronomical and molecular markers descriptors for precise cultivar identification.
Genomic prediction of leaf rust resistance to Arabica coffee using machine learning algorithms
(Escola Superior de Agricultura "Luiz de Queiroz", 2021) Sousa, Ithalo Coelho de; Nascimento, Moysés; Silva, Gabi Nunes; Nascimento, Ana Carolina Campana; Cruz, Cosme Damião; Silva, Fabyano Fonseca e; Almeida, Dênia Pires de; Pestana, Kátia Nogueira; Azevedo, Camila Ferreira; Zambolim, Laércio; Caixeta, Eveline Teixeira
Genomic selection (GS) emphasizes the simultaneous prediction of the genetic effects of thousands of scattered markers over the genome. Several statistical methodologies have been used in GS for the prediction of genetic merit. In general, such methodologies require certain assumptions about the data, such as the normality of the distribution of phenotypic values. To circumvent the non-normality of phenotypic values, the literature suggests the use of Bayesian Generalized Linear Regression (GBLASSO). Another alternative is the models based on machine learning, represented by methodologies such as Artificial Neural Networks (ANN), Decision Trees (DT) and related possible refinements such as Bagging, Random Forest and Boosting. This study aimed to use DT and its refinements for predicting resistance to orange rust in Arabica coffee. Additionally, DT and its refinements were used to identify the importance of markers related to the characteristic of interest. The results were compared with those from GBLASSO and ANN. Data on coffee rust resistance of 245 Arabica coffee plants genotyped for 137 markers were used. The DT refinements presented equal or inferior values of Apparent Error Rate compared to those obtained by DT, GBLASSO, and ANN. Moreover, DT refinements were able to identify important markers for the characteristic of interest. Out of 14 of the most important markers analyzed in each methodology, 9.3 markers on average were in regions of quantitative trait loci (QTLs) related to resistance to disease listed in the literature.