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This study assessed the effect of acetylsalicylic acid (ASA) and 1-methylcyclopropene (1-MCP) to control anthracnose in papaya (cultivar Golden). Disinfested-surface fruits were inoculated with Colletotrichum gloeosporioides and then the compounds were applied. The lesion diameters and the physical-chemical properties were analyzed. Assays were carried out with ASA and 1-MCP targeting the control of anthracnose and maintenance of the fruit's physical-chemical properties. The effect of ASA (20 mM; 20 min) on reducing lesion diameter occurred when applied before inoculation. Fruits treated with 1-MCP (300ppb) for 12 h showed a smaller lesion diameter than control. For the physical-chemical analysis, fruit treated with 1-MCP (200; 300 ppb; 12h) maintained fruit firmness, delayed fruit ripening and fruit fresh weight loss.

Neste trabalho avaliou-se o efeito do ácido acetilsalicílico (ASA) e 1-metilciclopropeno (1-MCP) no controle da antracnose do mamão (cv Golden). Para isso o Colletotrichum gloeosporioides foi inoculado em frutos superfícialmente desinfestados para depois aplicar-se os compostos. O diâmetro das lesões e as características físico-químicas foram determinadas. Os ensaios foram conduzidos com ASA e 1-MCP visando o controle da antracnose e a manutenção das características físico-químicas do fruto. O efeito do AAS (20 mM; 20 min) na redução do diâmetro da lesão ocorreu quando aplicado antes da inoculação. Frutos tratados com 1-MCP (300 ppb) por 12 horas apresentaram menor diâmetro de lesão que controle. Para a análise físico-química, frutos tratados com 1-MCP (200; 300 ppb; 12h) mantiveram a firmeza, o amadurecimento tardio e a perda de massa fresca dos frutos.

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The original version of this article unfortunately contained two mistakes in the "Materials and methods" section, subsection "DNA extraction and PCR" of the article. The correct information is given below.

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The use of cover crop in agricultural fields has been well elucidated, especially regarding nitrogen fixation from legume crops and their function as weed protection. Furthermore, to cover crops can benefit the soil microbial community. This study aimed to evaluate and compare the benefits of mulching and cover cropping systems on soil microbial growth and activity, and their effects on plant mineral nutrition in pomelo (Citrus maxima ) and macadamia ( Macadamia integrifolia ) orchards. The treatments included: 1) control [Glyphosate herbicide (Roundup at 4 l per ha)], 2) manual weed control, 3) mulching with dead leaves from their respective trees (macadamia and pomelo), 4) millet, 5) faba bean, 6) millet + faba bean. All the treatments were applied for 120 days before soil and plant leaves were sampled for analyses. Plant mineral nutrition, soil microbial biomass C (MBC) and soil microbial biomass N (MBN); basal respiration (BRA), arbuscular mycorrhizal fungi (AMF) colonization (COL); number of AMF spores (SPO) in soil; total organic carbon (TOC) and total nitrogen (TN) were evaluated. Plant nutrition was not altered by the treatments; however, the MBC, COL and SPO markedly increased in response to mulching and faba bean + millet treatments. Especially in macadamia soils, these treatments had a great response to soil microbiology. Significant negative correlations were also detected for the COL, SPO, BRA and TOC with the Nutrient Balance Index (NBI). These results indicate that in short-term the cover cropping system is useful to improve the soil microbial growth and AMF formation in soils of pomelo and macadam orchards.

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The use of cover crop in agricultural fields has been well elucidated, especially regarding nitrogen fixation from legume crops and their function as weed protection. Furthermore, to cover crops can benefit the soil microbial community. This study aimed to evaluate and compare the benefits of mulching and cover cropping systems on soil microbial growth and activity, and their effects on plant mineral nutrition in pomelo (Citrus maxima ) and macadamia ( Macadamia integrifolia ) orchards. The treatments included: 1) control [Glyphosate herbicide (Roundup at 4 l per ha)], 2) manual weed control, 3) mulching with dead leaves from their respective trees (macadamia and pomelo), 4) millet, 5) faba bean, 6) millet + faba bean. All the treatments were applied for 120 days before soil and plant leaves were sampled for analyses. Plant mineral nutrition, soil microbial biomass C (MBC) and soil microbial biomass N (MBN); basal respiration (BRA), arbuscular mycorrhizal fungi (AMF) colonization (COL); number of AMF spores (SPO) in soil; total organic carbon (TOC) and total nitrogen (TN) were evaluated. Plant nutrition was not altered by the treatments; however, the MBC, COL and SPO markedly increased in response to mulching and faba bean + millet treatments. Especially in macadamia soils, these treatments had a great response to soil microbiology. Significant negative correlations were also detected for the COL, SPO, BRA and TOC with the Nutrient Balance Index (NBI). These results indicate that in short-term the cover cropping system is useful to improve the soil microbial growth and AMF formation in soils of pomelo and macadam orchards.(AU)

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Elucidation of the distinctive microbial taxonomic profiles of tropical fruit peels is the indispensable component of investigations aimed at the detection of microorganisms responsible for the post-harvest loss. The objective of the present work was to dissect the bacterial and fungal community of five tropical fruit peels (banana, guava, mango, papaya, and passion fruit) in wild (non-cultivated) and conventionally produced samples from Brazil. To that end, 16S rRNA-encoding gene and ITS rDNA amplicon analysis of the five tropical fruit peels were performed to discriminate the bacterial and fungal communities, respectively. The result showed that bacterial communities of the five types of fruit peels were by far more diversified than that of fungal communities, independent of the type of production system involved. Among the investigated fruits, non-cultivated papaya peels hosted the most diversified bacterial community while the least bacterial community diversity was found in the conventionally produced papaya fruit peels. The gene amplicon analysis clearly discriminated the bacterial community into their respective classes, while fungal communities were better classified in their phyla, yet with clearer component discrimination of fungal community based on the type of cultivation system practiced. Conventionally produced banana and non-cultivated passion fruit peels were characteristically dominated by fungal and bacterial groups, respectively. Overall, in conventionally produced fruit peels, bacterial community was mainly composed of Proteobacteria, Actinobacteria, and Bacilli. The result provided a broad microbial diversity profile that could be used as an important input for seeking alternative fruit spoilage control and post-harvest treatments.

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Abstract This research evaluated the monthly variation of plant mineral nutrition in six species of fruit trees over a year. Leaf samples were taken from the fruit trees and nutritional status (N, P, K, Ca, Mg, Fe, Zn, Cu, Mn, and Mo) was determined in the leaves in a month basis from April until November for apple, persimmon and peach. Mandarin mineral nutrition was monitored for one year, and grape and fig from May to November. Using this data, the Diagnosis Recommendation Integrated System (DRIS) was also calculated to evaluate the nutrient balance in the plants. The concentration of N and P had seasonal differences, especially in apple and peach, which reached the peak during the summer. Apple, fig, and grape trees had large ranging on their mineral contents over the year, especially with the P and K levels reaching the minimum during the harvesting season. However, the seasonal changes in leaf micronutrient concentrations were not uniform and not affected by phenological stage. The DRIS data demonstrated that mandarin had the best nutrient balance compared to others and that K was the most limiting element among the fruit trees. In summary, the current data suggest the occurrence of a significant seasonality in mineral nutrition in these six fruit trees, especially in temperate ones.

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An experiment was carried out under greenhouse conditions to observe the distribution of arbuscular mycorrhizal (AM) hyphae in the rhizosphere of papaya and other plants under intercropping system. Special acrylic root boxes with three compartments, separated by nylon mesh screens, were constructed. One outer compartment contained seedlings of papaya (Carica papaya L.) and other contained seedlings of bahiagrass (Paspalum notatum Flügge) or millet (Pennisetum glaucum L. R. Br.). The central compartment was inoculated with an AM fungus (Gigaspora margarita). In another experiment, the outer compartments were treated with 25 percent MeOH eluates of bahiagrass (BRE) and millet (MRE) root extracts. A control box, containning only papaya seedlings was also prepared. Hyphal density, root infection levels and spore numbers were higher in the bahiagrass and millet compartments than in the papaya compartment. Similar results were found for the percentage of AM infection and the number of AM spores. In the compartments treated with BRE and MRE the density of AM hyphae was around 20 percent, and a few spores were found in those compartments. Few AM hyphae and spores were observed in the control compartment.

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