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Revista Ceres, Volume: 71, Publicado: 2024
  • Thermal, hydric, and physiological effects on watermelon due to wetted area variation Agricultural Engineering

    Barros, Allan Cunha; Silva, Ricardo Barros; Santos Neto, Antônio Lucrécio dos; Vellame, Lucas Melo; Santos, Maria Deyse Silva dos; Aguiar Netto, Antenor de Oliveira

    Resumo em Inglês:

    ABSTRACT The objective of this research was to evaluate leaf temperature, and watermelon yield components under wetted area percentages (PW) in irrigation located in the Agreste region of Northeastern Brazil. Two experiments were carried out in 2018 and 2019. The adopted statistical design was randomized blocks, with six replications and four treatments, in 2018: P1 = 13%, P2 = 14%, P3 = 19%, and P4 = 22%, in 2019: P5 = 12%, P6 = 15%, P7 = 16%, and P8 = 21% of PW. The meteorological variables analyzed were: air temperature (Ta) and rain. The experimental evaluations consisted of measuring the temperature of the plant’s vegetative canopy, tensiometry, mass, and BRIX. Air temperature was not a limiting factor for watermelon growth and development. The average was 195.88 mm, and the average leaf temperature of watermelon is 29.5 °C, a value lower than Ta. There was no statistically significant difference for fruit mass and BRIX, where the overall mean was 10.82 and 10.46 kg, respectively. Therefore, it is feasible to irrigate watermelon with wetted area percentages ranging from 12 to 22%, in localized irrigation systems, without generating physiological damage and reducing agricultural productivity and fruit quality.
  • Photosynthetic activity in avocado leaf ontogeny as a result of compatibility rootstock/scion in three locations in Colombia Physiology And Morphology Applied To Agriculture

    Cano-Gallego, Lucas Esteban; Bernal-Estrada, Jorge Alonso; Hernández-Arredondo, Juan David; Correa-Londoño, Guillermo Antonio; Córdoba-Gaona, Oscar de Jesús

    Resumo em Inglês:

    ABSTRACT In Colombia, the evidence of rootstock/scion incompatibility in avocado cv. Hass graft union has been increasing, generating concern among farmers. The objective was to evaluate the photosynthetic response of the avocado trees due to rootstock/scion compatibility in three locations. A split plots design with a blocking factor per locality was used. The main plot corresponded to the type of graft union (compatible and incompatible) and the subplots to leaf age during the 2020 and 2021 seasons. Climatic (water balance) and gas exchange variables (photosynthesis, transpiration, stomatal conductance, leaf temperature, and efficiency in instantaneous water use) were measured. The results indicate that the photosynthetic performance was not affected when the water balance was negative. Compatibility did not significantly affect gas exchange variables (A, gs, E, Tl, and WUEi) during the main and secondary harvest period. The leaf age/harvest period interaction shows that during the first months of leaf development, A, gs, E, and Tl are greater and are detrimental over time. It is concluded that the rootstock/scion compatibility does not significantly modify the capacity to assimilate CO2. At the same time, the variation in avocado photosynthetic activity depends on the age of the leaves and the harvest season.
  • Physicochemical characterization of watermelon accessions from traditional agriculture with resistance to Fusarium wilt Plant Breeding Applied To Agriculture

    Silva, Amanda Rodrigues da; Ishikawa, Francine Hiromi; Costa, Antonio Elton da Silva; Cunha, Fábio Sanchez da; Galhardo, Cristiane Xavier

    Resumo em Inglês:

    ABSTRACT Watermelon has great importance due to its nutritional properties. The aim of this work was to study accessions classified as resistant to fusariosis. Twelve accessions and two cultivars, Sugar Baby and Charleston Gray (controls), were characterized for watermelon fruit quality descriptors. The experiment was conducted in Petrolina-PE, over two production cycles in a randomized complete block design, with three repetitions and five plants per plot. Two fruits per plot were sampled for characterization. Ten quantitative and seven qualitative descriptors were evaluated. For the qualitative traits, dissimilarity measures were determined by a matrix of Euclidean distance. At the second harvest, most accessions had higher organic acid and vitamin C content in the pulp and higher soluble solids (°Brix) content. The accessions were divided into four groups according to the Tocher method. There is variability among the evaluated accessions, and the accessions BGH-Univasf 40, BGH-Univasf 169, and BGH-Univasf 177 are potential sources for use in watermelon breeding programs. Accessions BGH-UNIVASF 76, BGH-UNIVASF 128, and BGH-UNIVASF 185 (Citrullus lanatus var. citroides) performed well in terms of total production, fruit mass, and vitamin C content.
  • Growth analysis of Ambrosia artemisiifolia Crop Production

    Rockenbach, Ana Paula; Rizzardi, Mauro Antônio

    Resumo em Inglês:

    ABSTRACT We hypothesized that common ragweed has rapid growth and development in shoots and roots, which explains its high potential for establishment in the areas, as well as the high regrowth capacity after cutting or application of contact herbicides. This study aims to evaluate the growth of the specie Ambrosia artemisiifolia. The treatments consisted of collection periods of common ragweed plants at fixed intervals of ten days, from 15 to 95 days after emergence (DAE), totaling nine evaluations. In each collection, the aerial part and the roots were evaluated. In the aerial part, stature, leaf area, number of leaves, and dry mass were evaluated. From these data, the absolute growth rate, relative growth rate, net assimilation rate and leaf weight ratio were calculated. The length, surface area, volume, average diameter, number of root tips, and dry mass were evaluated in the root. The common ragweed plants show rapid growth after emergence, with a similar response in aerial parts and roots. The potential for competition with crops is expressive. Furthermore, due to growth and development characteristics, the potential for regrowth is high and impacts the difficulties in controlling this species. Thus, the authors indicate that control should be carried out within a maximum of 25 days after emergence.
  • Chemical thinning programs for vigorous ‘Maxi Gala’ apple trees under black anti-hail netting in Southern Brazil Crop Production

    Marchioretto, Lucas De Ross; Rossi, Andrea De; Marodin, Gilmar Arduino Bettio

    Resumo em Inglês:

    ABSTRACT Hail netting increases natural fruitlet drop. Mixing lower concentrations of Plant Growth Regulators (PGRs) and spraying on more advanced fruitlets could promote adequate crop load management and improve fruit quality. The objective of this study was to evaluate thinning programs with low concentrations of PGRs sprayed at advanced fruitlet size looking for reducing crop load, enhancing fruit quality, and preserving yield. On 2020/21 and 2021/22, in an orchard covered with hail netting in Bom Jesus-RS, eight programs were tested on vigorous ‘Maxi Gala’: Benzyladenine (BA)+Gibberellic acid4+7 (BA-GA) at full bloom (FB) and BA+Ethephon (ETH) at 15mm; BA-GA at FB and Naphthalene acetic acid+Carbaryl (CB) at 7 mm; BA-GA at FB and BA+CB at 15 mm; ETH+CB at 15 mm and Metamitron (MM)+ETH at 20 mm; BA-GA at FB and BA at 7 mm and MM at 20 mm; MM at 7 mm and MM at 20 mm; Manual Thinning Only; Untreated Control. The treatments containing CB reduced fruit set, although diminished yield unsustainably. All PGR programs improved fruit quality. In conclusion, BA-GA at FB and BA+ETH at 15 mm, and MM at 7 mm and MM at 20 mm reduce crop load, preserve yield and improve fruit quality.
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