<p>Rust 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.</p>
In the rooting process of Arabica coffee cuttings, plant hormones are used for inducing root formation. However, synthetic molecules cannot be used to form organic seedlings. The objective of this work was to evaluate the effect Cyperus haspan extract and different concentrations and types of humic substances on Arabica coffee cuttings. Arabica coffee shoots were collected, and cuttings containing at least two buds were taken. The experiment had a three-factor design, 2 (presence or absence Cyperus haspan extract) x 2 (humic or fulvic acid) x 4 (0, 10, 25 and 50 mg dm-³ concentrations). The following vegetative data were evaluated: shoot height (cm), survival, remaining leaves, leaf pairs, vigor, number of shoots,root length, area root, volume root, diameter root and fresh and dry mass were also evaluated. The enzyme activity of H+-ATPase, catalase, superoxide dismutase, alcohol dehydrogenase and esterase was also quantified. The results showed that the Arabica coffee cutting rooting rate was increased when treated with humic acid at a concentration of 10 mg dm-³ in the presence of Cyperus haspan extract. The lowest oxidative stress was observed in the 10 mg.dm-³ humic and fulvic acid treatments, regardless of the use of the extract.
his study aimed to analyze the economic feasibility of implementing and using the necessary infrastructure to collect rainwater from the roof of free-stall sheds in a dairy production system in southern Minas Gerais, Brazil. Specifically, the total cost (TC), total operating cost (TOC), and actual operating cost (AOC) of a cubic meter of rainwater and the break-even point in cubic meters were estimated. The research was conducted from January to December 2017 on a property located in the south of Minas Gerais. The following MOP scenarios were analyzed: most likely (Scenario 1), optimistic (scenario 2), and pessimistic (scenario 3). The grant value of the Das Velhas River basin was considered for the most likely scenario, as it has the most similar value with that of the basin surrounding the Furnas reservoir, in which the property is inserted. The grant value for water collection and consumption from the Paraíba River basin was considered in Scenario 2, as this Federal basin has the lowest grant value. The grant value for water collection and consumption from the Piracicaba, Jundiaí, and Capivari river basins was considered in Scenario 3, as these basins have the highest prices for the cubic meter of the collected and consumed water. The implementation of the infrastructure for collecting rainwater from the roof of free-stall sheds under the studied conditions was economically unfeasible for all scenarios, with negative net present values (NPV). Simple and discounted paybacks were longer than the proposed horizon. The internal rate of return (IRR) could not be estimated due to the negative values of the net cash flow. The benefit-cost ratios (BCR) were unsatisfactory (lower than 1). The TC values for rainwater collection from the roof of free-stall sheds were R$ 23,206.59 and R$ 20,489.25 for scenarios with interest rates of 8.50 and 6.99%, respectively, while the TOC value was R$ 7,850.30 for all analyzed scenarios. The unit values for TOC and AOC were R$ 9.9024/m3 and R$ 1.3060/m3 of collected water, respectively. The break-even point could not be estimated in the studied scenarios, as the variable cost per cubic meter of water collected from the roof of the free-stall shed was higher than the grant value charged by the water management committees of the different studied basins.
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