Coffee Science (E-Journal)
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EFFECTS OF SHADE TREE SPATIAL DISTRIBUTION AND SPECIES ON PHOTOSYNTHETIC RATE OF COFFEE TREES
Get PDFThe use of shade trees in coffee fields have been motivated by climatic changes. However, microclimatic conditions in shaded coffee fields differ due to shade tree spatial distribution and species, altering physiological responses of coffee trees. This study aimed to evaluate the effects of shade tree spatial distribution and species on coffee trees photosynthetic rate in two growth seasons, of high (HSD) and low (LSD) sink demand. The experimental design consisted of randomized blocks with three replicates in split-split-plots. Plots were the shade tree species: Anadenanthera falcata, Cassia grandis and Peltophorum dubium. Split plot was formed by five distances between coffee trees and shade tree trunks: coffee trees on planting row of shade trees, distancing one (D1L) and five (D5L) meters from shade trees trunk; coffee trees on inter-rows of shade trees, parallel to D1L and D5L (D1E and D5E); coffee trees distancing 77 meters from shade tree trunks, in a full-sun field (PS). The split-split-plots correspond to coffee tree canopy exposure to the sun: branches facing North or South. Shade trees canopy density and occupation was evaluated with a convex densiometer. Photosynthetic rate (Pn)and photosynthetic active radiation (PAR) were measured with an Infrared Gas Analyzer (IRGA) on two time-frames, between 7.00 and 9.00 solar hours and between 11.00 and 13.00. Shade tree canopy density and occupation was not homogenous during the change of seasons and shift due to spatial distribution, which also changes PAR levels. Shade trees reduce PAR to more suitable values for coffee tree exploitation, especially on D1L and D5L. During HSD, shading did not affect Pn, which was greater in branches facing North. Yet, in LSD, between 11.00 and 13.00, coffee trees shaded with A. falcata showed greater Pn than at PS. Coffee trees shaded with C. grandis at D5L and D1E had greater values of Pn than PS
INITIAL STAGES OF INFECTIOUS PROCESS OF Pseudomonas syringae pv. garcae IN COFFEE LEAVES
Get PDFBacterial blight of coffee (Pseudomonas syringae pv. garcae) (PSG) has been causing damage and losses to coffee growing. However, initial stages of the infectious process should be described in order to understand the relationship cycle and to propose efficient management strategies. This study described the initial stages of infectious process of the PSG in coffee leaves over time. The bacterial penetration sites studied were stomata, leaf margins, and wounds. Coffee seedlings received 50μL inoculum suspension at marked points on the abaxial face and leaf margins, and around wounds. By 30 minutes, 1, 3, 6, and 12 hours after inoculation, leaf disks collected at inoculated points were analyzed with scanning electron microscopy. One hour after inoculation, bacterial groups could be seen as result of cell multiplication. Subsequently, the number of grouped bacteria increased proportionally over time. A growing population concentration was found near stomata, wounds, epidermal appendages, and wax layer on leaf margins and leaf tip. Bacteria were positioned in their long axis starting from structures, thus creating a population gradient and displacement flow toward penetration pathways. Initial stages of infectious process occurred in all penetration sites, thus it was not possible to determine a preferred pathway
INDAZIFLAM APPLICATION IN NEWLY TRANSPLANTED ARABICA COFFEE SEEDLINGS
Get PDFWeed management is one of the main and most problematic cultural practices used in coffee plantations. Slow growth, broad spacing associated with scarce registered products for weed control at an early crop stage, are the main problems faced by producers. Therefore, it is desirable for new herbicidal molecules to be registered for this crop, as is the recent case of indaziflam. This study aimed to know the influence of indaziflam on the morphological characteristics of coffee plants and to propose alternatives to reduce its effects on plants. Therefore, the effects of this herbicide on two arabica coffee cultivars were studied, as well as the association of this herbicide with protection of the seedling collar (PVC pipes and bovine manure). Controls on weeds, possible intoxications on seedlings and effects on the main morphological characteristics of coffee plants were evaluated. The morphological growth of cultivar 144 is naturally higher than that of cultivar IBC 12. Although treatments with the use of indaziflam cause intoxication in the seedlings, a reduction in plant damage was observed over time, and the damage was insignificant. In general, it was observed that cultivar IBC 12 suffered minor intoxications, but it is more sensitive to the presence of indaziflam, since it presented greater damage in the morphological variables. The use of manure with the PVC pipe can be an alternative to reduce the effects of this herbicide, as it reduced the effects of the product on the root system of this cultivar. It is concluded that the application of indaziflam causes mild symptoms in coffee plants independent of the planted cultivar. Indaziflam causes reduction in seedling morphology, and this effect is dependent on the cultivar used. The use of manure associated to the PVC pipe can be an alternative to reduce the effects of indaziflam, mainly in the root system of coffee plants
EFFECT OF INTERCROPPING IN SHADING WITH CROTALARIA ON THE INITIAL DEVELOPMENT OF COFFEE TREE
Get PDFCoffee cultivation in Brazil is still predominantly in full sun. However, the shading technique has gained prominence to increase the sustainability and profitability of production. Coffee intercropping legumes, besides contributing to shading, act as green manure, improving soil characteristics. Thus, in this study the objective was evaluating the shading intercropping effect on the initial development of coffee trees. The experiment was carried out at Sítio Santa Felicidade, municipality of Campestre - Southern Minas Gerais. Four species of the Crotalaria genus were used and one control treatment without any intermediate species, totaling 5 treatments. The planting was carried out in 4 replicates per treatment, in a randomized block system (DBC), with 16 coffee plants per plot. The 10 central plants were used for evaluation. The variables analyzed were: seedling setting (%), plant height (cm), leaf area index (LAI), number of plagiotropic branch internodes and 50 cm from ground level (cm²), temperature (°C) and soil moisture (%). Data were statistically interpreted by variance analysis and comparisons of averages performed by the Scott-Knott test at 5% probability, using the statistical software SISVAR®. It was observed that, except seedling setting (%) wherein there was no statistical difference among treatments, the other parameters showed positive responses in intercropping with crotalaria when compared to the control, showing the beneficial effect of the use of this legume when intercropped with coffee tree.
SHADING EFFECT ON COFFEE TREE IN FORMATION STAGE
Get PDFAccording to the Intergovernmental Panel on Climate Change, global warming is expected with temperature rise and changes in the rainfall in tropical regions, including soil warming, which may lead losses to perennial plants. This phenomenon causes researchers to search through science alternatives in order to minimize these impacts. The objective in this research was to evaluate the cultivation of different plants in a intercropping for the coffee tree shading and its influence on the seedlings establishment, development, coffee growth and the maintenance of lower soil temperatures. The experiment was carried out at the Santa Felicidade Site, Campestre - municipality - South of MG , located at 21 ° 43’ 12 “South and 46 ° 14’ 46” West at an altitude of 1.106 meters. The cultivar used was the Catuai IAC 144, was intercropped with the following species: maize (Zea mays L.), guandu (Cajanus cajan L.), crotalaria (Crotalaria spectabilis L.), mucuna (Stizolobium aterrimun) and control without any intercrop, totaling five treatments. The plants sowing for shading was performed using a manual planter and the planting was done in 4 plots per treatment, totaling 20 experimental units in a randomized block design with 14 coffee plants per plot. The 10 central plants were analyzed. At the end of the experiment, the following characteristics were evaluated: seedlings establishment, growth in height, average length of plagiotropic branches, number of internodes in plagiotropic branches, coffee canopy and soil temperature. The data were statistically interpreted by means of variance analysis. The means were grouped by the Scott Knott test at 5% probability using the statistical software SISVAR®. According to the results obtained the shading plants in intercropped with the coffee tree managed in the post-planting and first-year phases contributed to a better coffee tree development, observed mainly in the treatments using the Crotalaria and Guandu species
PHYTOTOXICITY AND GROWTH OF COFFEE PLANTS AS A FUNCTION OF THE APPLICATION OF HERBICIDE 2,4-D
Get PDFWeed control in coffee is of great importance for there is a great interference, standing out the competition for water, light and nutrients. Among the control methods, chemical control is highlighted as a function of its efficiency. However, the incorrect application of herbicides may imply the occurrence of drift, resulting in damage to coffee development due to phytotoxicity. In this context, the objective of this study was to evaluate the symptoms and phytotoxicity effects caused by the herbicide 2,4-D drift on the morphological, physiological and anatomical characteristics of coffee seedlings. The experiment was carried out in a greenhouse with ‘Topázio MG1190’ coffee seedlings (Coffea arabica L.), planted in 11-L pots. A randomized block design with four treatments and four replicates was used. The treatments were: 0%; 10%; 25% and 50% of the recommended commercial dose of 2,4-D (2.5 L.ha-1). Each plot consisted of three plants. The evaluations were performed at 74 days after implantation. Morphological, physiological, anatomical and phytotoxicity symptoms were evaluated as a function of the simulated herbicide drift. Coffee seedlings intoxicated by the herbicide 2,4-D presented hyponastic, chlorosis, shriveling and leaf anomalies. In the orthotropic branch, bending was observed in its extension, besides thickening in the collar region; in the plagiotropic branch, cracking was observed. Herbicide drift negatively affects the development of coffee plants. The coffee physiology was affected as a function of herbicide drift, but without damage to the leaf anatomy
INFECTION PROCESS OF Cercospora coffeicola IN IMMATURE COFFEE FRUITS
Get PDFCercosporiosis is caused by Cercospora coffeicola and represents very important coffee plants phytosanitary problem. Catuaí IAC 144 and Topázio cultivars at the F2 stage were inoculated with a conidial suspension. Samples were collected at 4, 8, 12, 24, 36, 48, 72, 96, and 168 hours after inoculation (hai) for scanning electron microscope studies. Fungal germination in epidermal surface occurred 4 hai; penetration only through epidermal wounds 12 hai, without appressoria; internal mycelial colonization at 72 hai. The infection in immature coffee fruits implies brown eyespot control management anticipation need, even before the first symptoms
SELECTION OF COFFEE PROGENIES WITH LARGE BEANS RESISTANT TO RUST AND CERCOSPORA LEAF SPOT
Get PDFRust is the main disease of coffee. Recently, cercospora leaf spot has grown in importance, intensifying defoliation and decreasing grain yield. The aim of this study was to use a mixed model approach to select the best progenies of "Big Coffee VL" for resistance to rust and cercospora leaf spot. We used 12 progenies with high bean yields. Based on bean size, leaves and plant size, plants within each progeny were classified as "small" (P), "medium" (M) and "large" (G). The experimental design was completely randomized, with six replicates and one plant per plot. Six measurements were carried out every 15 days for each plant by selecting 20 fully exposed leaves with higher and lower sun exposures. The measurements summarized disease severity using two diagrammatic scales to obtain the area of the leaf under rust or Cercospora leaf spot. A mixed model approach was used to calculate genotypic value (GV) and heritability estimates. The Mulamba and Mock index was used to select the most resistant progenies, in which the sum of rankings was weighted by a heritability value. Five progenies were selected; three progenies were G (G17, G9, and G12), one progeny was M (M5) and another progeny P (P23). Among these, M5 and P23 progenies are the most productive and may have potential use in future studies. The statistical approach used to predict promising genotypes facilitates the selection of genetically superior individuals for maximizing yields
IONIC SPECIATION IN A DYSTROPHIC RED LATOSOL UNDER COFFEE CROP AND HIGH DOSES OF GYPSUM
Get PDFThe cultivation of coffe crops in Brazil, especially on Latosols, has been increasing over the years, despite limitations such as aluminum toxicity, low fertility and very long drought periods. In this scenario, soil amendments to mitigate these restraints are necessary. Since these limitations are not restricted to the arable layer, application of gypsum becomes an efficient alternative to sustain soil fertility and deepen the root system to get water from the deeper layers of soil. However, high doses of gypsum can cause unbalance among Ca2+, Mg2+ and K+. The objective of this work was to evaluate these bases as well as their ionic pairs, and the presence of sulfate along the soil profile 16 months after the application of high gypsum doses in a Latosol under coffee crops. An inicial dose of gypsum was applied in the entire area, followed by four treatments, in triplicate and randomized blocks, set as follows: G0 - zero gypsum applied over the planting line after the initial soil preparation; G7- 7 t ha-1 of gypsum in the planting line (1.75 kg m-1); G56 - 56 t ha-1 of gypsum in the planting line (14 kg m-1), all with brachiaria between the coffee planting lines; and CV7 - 7 t ha-1 of gypsum in the line and no brachiaria between the planting lines. The soil profile was sampled in layers up to 2.40 m depth and the soil solution was extracted by suctioning the sample-saturated paste. Following this extraction, the soil solution was analyzed by combustion for total carbon contents, ion chromatography and ICP-OES/flame photometry, for chemical species, and speciation was done using Minteq software. After 16 months of gypsum application, 96% of K+ in soil solution was at 0.35 to 0.45 m in its free form. Leaching of Ca2+ and Mg2+ occurred predominantly in their free forms, although a more significant contribution of CaSO4 0 and MgSO4 0 ionic pairs was observed when compared to K2SO40
FUZZY LOGIC IN THE SPATIAL AND TEMPORAL DISTRIBUTION IN THE QUALITY OF THE BEVERAGE IN CONILON COFFEE
Get PDFThe objective in this study was to evaluate the spatial and temporal variability of the beverage quality by applying the fuzzy classification in the final global sensory analysis, for Coffea canephora Pierre ex A. Froehner, in two consecutive harvests. The studied variables were: fragrance (aroma), flavor, bitterness (sweetness), set, balance, cleaning, aftertaste, mouth feel, uniformity, salinity (acidity) and drink (global note). To the average overall scores of the drinks obtained on the cup-tasting at 80.0 points of a sampling, the mesh has applied the function of association of the fuzzy classification linear model to determine the degree of pertinence. The data were analyzed by the descriptive statistics and then by geostatistics to verify the existence and quantify the degree of spatial dependence of the variables. In the interval classified as “very good coffee” is found in the global average grade, in the two harvests. The methodology fuzzy applied in the global beverage note of the coffee conilon seminal made it possible to determine their spatial variability in the same distribution pattern in the two harvests, close ranges, and adjustments to the spherical model, which was confirmed by the spatial correlation of 61.6% among the fuzzy maps for the global scor