Filtros solares inorgânicos incorporados à cera de carnaúba e incidência de mancha preta em tangerinas

The objective of this work was to evaluate the effect of zinc (ZnO) and titanium (TiO2) oxides, added to carnauba wax emulsions, on the incidence of citrus black spot (CBS) caused by Phyllosticta citricarpa and, consequently, on tangerine quality. Wax emulsions blended with ZnO or TiO2 were sprayed up to concentrations of 8% on late-season tangerine cultivars. Three experiments were carried out in a randomized complete four-block design, with two control treatments – one with the application of only the carnauba wax emulsion and the other without the application of the emulsion. The spraying of ZnO and TiO2 reduced the incidence of the disease on the harvested fruit; however, the increase in the concentrations of the oxides did not improve CBS control. Two consecutive applications of the oxides reduced the photosynthetic activity of the plants, negatively affecting yield, and caused damage to fruit peel. Tangerines infected artificially with 105 conidia mL-1 of P. citricarpa, before or after the sprayings of the photoprotective films, showed a reduced CBS incidence. The treatments with the application of only carnauba wax do not differ from those with films combined with ZnO and TiO2 regarding the control of CBS incidence. The addition of inorganic oxides to the carnauba films limits the photosynthetic activity and reduces the yield of the plants, besides damaging the visual quality of the tangerines.O objetivo deste trabalho foi avaliar os efeitos dos óxidos de zinco (ZnO) e titânio (TiO2), adicionados à emulsão de cera de carnaúba, sobre a incidência de mancha preta dos citros (MPC) causada por Phyllosticta citricarpa e, consequentemente, sobre a qualidade de tangerinas. Emulsões de cera com adição de ZnO ou TiO2 foram aplicadas a concentrações de até 8% em cultivares tardias de tangerinas. Foram realizados três experimentos, em delineamento de quatro blocos completos ao acaso, com dois tratamentos controle – um com a aplicação apenas da emulsão de cera de carnaúba e outro sem a aplicação da emulsão. As pulverizações com ZnO e TiO2 reduziram a incidência da doença em frutos colhidos; no entanto, os aumentos nas concentrações dos óxidos não melhoraram o controle da doença. Duas aplicações consecutivas dos óxidos inibiram a atividade fotossintética das plantas, tendo afetado negativamente a sua produção, e causaram danos na casca das frutas. Tangerinas infectadas artificialmente com a suspensão de 105 conídios mL-1 de P. citricarpa, antes ou depois da pulverização dos filmes, apresentaram menor incidência de MPC. Tratamentos com a aplicação apenas da emulsão de carnaúba não diferem dos com filmes preparados com ZnO e TiO2 quanto ao controle da MPC. A adição de óxidos inorgânicos aos filmes de carnaúba limita a atividade fotossintética e reduz a produtividade das plantas, além de prejudicar a qualidade visual das tangerinas

Efeito do molibdênio na produção e nos teores foliares de nutrientes do morangueiro

Strawberries (Fragaria x ananassa Duch.) cv. Campinas were cultivated in nutrient solution using five levels of molybdenum (Mo), 0.0010 ppm, 0.010 ppm, 0.10 ppm, 1.0 ppm and control (without applying molybdenum). The experiment was carried out in greenhouse and phytothron at Agronomy School of the Federal University of Rio Grande do Sul, Brazil, to evaluate the changes in the mineral status of the leaves and the quality of the berries. The concentration of Mo in the leaves, at the beginning of fruiting stage, varied from 0.5 ppm to 64 ppm. No visual symptoms of deficiency or toxicity were observed. The total N in the levels was affected significantly by Mo and this can probably be attributed to its toxic effect. However nitrate, P, K, Ca, Mg and leaf area were not affected by the treatments. Total solid solubles, acidity, total solid solubles/acidity and ascorbic acid contents of the berries were not influenced by Mo. Average weight of the berries were affected by treatments and presented a quadratic regression response.Morangueiros (Fragaria x ananassa Duch.) cv. Campinas (IAC 2712) foram cultivados em solução nutritiva e submetidos a cinco níveis de molibdênio (Mo): 1,0 ppm, 0,10 ppm, 0,010 ppm, 0,0010 ppm e testemunha (sem aplicação de Mo). A fase experimental foi conduzida em casa de vegetação e câmara de crescimento, na Faculdade de Agronomia da UFRS para avaliar as alterações no estado nutricional das plantas e na qualidade de seus frutos. A concentração de Mo nas folhas, colhidas de plantas no estádio de início de frutificação, aumentou linearmente, de 0,5 ppm a 64 ppm. Não se verificaram sintomas de deficiência ou toxidez. Os teores foliares de nitrato, P, K; Ca e Mg e a área foliar não foram afetados pelos níveis de Mo; no entanto, os teores de N-total diminuíram linearmente com o aumento da concentração de Mo, o que se atribui a um possível efeito de sua fitotoxidez. Os sólidos solúveis totais (SST), a acidez titulável, a relação SST/acidez e os teores de ácido ascórbico dos morangos não foram afetados pelo Mo. O peso médio de frutos sofreu um efeito quadrático, aumentando até a concentração de 0,10 ppm de Mo na solução

‘URS Campestre’ seedless orange: a new mutant with female sterility

Seedlessness in fruit is a trait that is much sought after by juice making industries. Close to the city of São Sebastião do Caí, in the state of Rio Grande do Sul (RS), Brazil, a new mutant orange originating from natural mutation was identified and selected as a seedless material. To determine the mechanisms involved in the absence of seeds, the reproductive structures of this new mutant by comparison with a Valencia sweet orange as control, a cultivar with a profusion of seeds, was analyzed in terms of meiotic behavior, meiotic index, pollen viability, in vitro germination, and ovule features to determine the grounds for seed absence. Other morphological analyzes allowed for visualizing the structures of normal appearance and size in both cultivars. Meiotic analysis identified chromosome normal pairing with a predominance of bivalents at diakinesis and metaphase 1. URS Campestre flowers at different developmental stages had anthers and ovaries whose dimensions are typical while pollen grain analysis pointed to a standard developmental pattern, normal meiosis, high viability (84 %) and elevated in vitro pollen tube germination rates (63 %). The cv. Valencia and URS Campestre ovules had a similar shape and morphology, sharing an anatropous orientation, and two integuments. In the internal ovule analyses of Valencia sweet oranges, normal embryo sac cells were identified: presence of one egg cell and two synergids, three antipodes and a bigger and central cell containing two polar nuclei. However, the analysis of ovules from URS Campestre reveals an apparent senescence or non-formation of an embryo sac, where only a few highly stained and collapsed cells could be identified. These results led to the conclusion that female sterility in URS Campestre, with a total absence of a female gametophyte, is the limiting factor for fertilization and seed production

Dispositivo analisador de impacto, processo de produção e método de análise de impacto

Universidade Federal do Rio Grande do SulMatemáticaEngenhariaAgronomiaDepositad

Gerbera leaf nutritional status as a cut flower cultivated with different doses of nitrogen and calcium

Vegetative tissue analyses might help to diagnose nutritional status of a crop. Foliage diagnosis is an effective method to set up balanced fertilization procedures. The current work aims to evaluate nutrient contents of two gerbera leaf sampling periods as a cut flower cultivated in pots with different doses of nitrogen (N) and calcium (Ca) under greenhouse conditions. The experiment was carried out in a protected environment, shelter type, in a container containing substrate in a 3x3+1 factorial scheme. Three doses of N (0.07, 0.15 or 0.2 g L-1) or three doses of Ca (0.02, 0.03 or 0.04 g L-1) were applied every 15 days. Control plants did receive neither N nor Ca. The substrate was analyzed before and after cultivation, and at the end of production years, as well as completely expanded leaves were collected for nutrient analyses. There was not significant interaction between N and Ca doses. Regarding the sampling period or doses of N and Ca, the determined macronutrient concentrations were in the following order of NKCaPSMg. The micronutrient concentrations were in the following order of FeMnBZnCu. Except for K, all the other nutrient concentrations were in the recommended range for gerberas production

Drying of corn strains harvested as cobs for selection of mother plants for seed production

No presente trabalho, o objetivo foi avaliar a sensibilidade de diferentes genótipos de milho colhidos em espigas à secagem, realizando-se a secagem artificial em diferentes teores de umidade de colheita e em diferentes temperaturas de secagem. Foram cultivadas seis linhagens de milho da empresa DuPont, divisão Pioneer Sementes Ltda, no distrito de Morrinhos, GO. As espigas foram colhidas manualmente, em três graus de umidade (40, 35 e 30%) e secadas artificialmente em dois secadores de pequena escala, a 35 e 43 ºC, até atingirem teor de água de 10 a 12%. Após a secagem as espigas foram debulhadas manualmente e, em seguida, tratadas com fungicidas e enviadas ao laboratório para os testes de germinação, teste de frio e teste frio modificado.Foram observadas diferenças estatísticas nas variáveis avaliadas permitindo concluir que a sensibilidade à secagem de sementes de milho colhidas em espiga é dependente da linhagem.Temperatura do ar de secagem de 43 °C acarreta perdas qualitativas das sementes nas linhagens avaliadas. As linhagens 3 e 6 apresentaram melhor qualidade fisiológica quando a colheita foi realizada com teores de água das sementes entre 35 e 40%.In this study, the objective was to evaluate the sensitivity of different genotypes of harvested corn cob to drying, performing artificial drying of cobs harvested at different moisture contents and drying temperatures. Six maize lines from DuPont division Pioneer Seeds Ltd., District of Morrinhos – GO were grown. The ears were manually harvested at three moisture contents (40, 35 and 30%) and dried artificially in two small-scale dryers at 35 and 43 °C until a water content of 10 to 12%. After drying, the cobs were shelled manually and then treated with fungicides and sent to the laboratory for the germination test, cold test and modified cold test. Statistical differences in variables assessed permit to conclude that the sensitivity of drying corn seed harvested is dependent on the strain. Drying at a temperature of 43 °C leads to loss of seed quality in the tested strains. The strains 3 and 6 showed better physiological quality when harvested with water content of 35 to 40%

Uso de compostos nucleofílicos de calcogênios ou aminoácidos como reagentes para redução ou eliminação de patulina em bebidas e processados alimentares de frutas

Universidade Federal do Rio Grande do SulTecnano Pesquisas e ServiçosAgronomiaFarmáciaDepositad