Some forages release allelopathic substances into the environment, and may prevent consortium with arboreal species in pastures. The objective of this work was to evaluate photosynthetic characteristics of pequizeiro plants (hereafter pequi) influenced by concentrations of residues of the forage species Urocholoa decumbens, Melinis minutiflora and Paspalum notatum. The treatments consisted of pequi cultivation under aerial residues of the three forage species mixed to the substrate in four concentrations (1, 2, 3 and 4% mass/mass), plus an additional treatment (comparative control) with pequi cultivated on the substrate without waste. The following parameters were evaluated: photosynthetic rate, stomatal conductance, transpiration rate, relationship between internal and external CO2 concentration (Ci/Ca), maximum quantum yield, effective quantum yield of FS II, electron transport rate, nonchemical quenching and chlorophyll index, concerning the content of chlorophyll a, b and total in pequi plants at 50 and 100 days after transplanting (DAT), and the relative production of dry matter at 100 DAT. At 50 DAT, the following photosynthetic variables were affected in pequi plants: A, gs, chlorophyll a, chlorophyll b and total chlorophyll when cultivated in the presence of forage residues. At 100 DAT, the following photosynthetic variables were affected in pequi plants: A, Fv/Fm, ETR, NPQ, chlorophyll a, chlorophyll b and total chlorophyll, when cultivated in the presence of forage residues. Pequi plants had reduced relative dry matter yield when grown in the presence of U. decumbens. This variable was also affected when pequi was grown in increasing concentrations of residues of the species U. decumbens, M. minutiflora and P. notatum.

Information about the response of onion to different potassium doses may contribute to optimizing the use of fertilizers and, consequently, make the activity more profitable and environmentally sustainable. In this context, the aim of this study was to evaluate the effects of doses of potassium on onion yields. Two field experiments were carried out in the periods of September to December 2012 and April to July 2013. The experimental design used was completely randomized blocks with four replications. The treatments corresponded to the potassium doses (0, 36, 72, 108, 144 and 180 kg ha-1 of K2O). Potassium fertilization promoted an increase in the content of K in the leaf, commercial and total yield, with the maximum obtained in the dose of 180 kg ha-1 of K2O. The maximum overall and commercial yields were respectively 54.69 and 54.12 t ha-1 in the experiment of September to December 2012 and 47.39 and 46.39 t ha-1 in that of April to July 2013.

Intercropping is a production system that can reduce the production cost and increase the profitability of vegetable producers, since it permits more efficient land and agricultural inputs use. In order to evaluate the effect of lettuce plant density on the economic feasibility of lettuce-rocket intercropping system over two growing seasons (winter and summer), two experiments were conducted in the field at São Paulo State University “Júlio de Mesquita Filho” (UNESP), Jaboticabal, São Paulo, Brazil. The treatments consisted of five lettuce-rocket intercrops with spacing between lettuce rows of: 0.20; 0.25; 0.30; 0.35 and 0.40 m, five sole crop of lettuce in the same spacing between rows adopted in the intercropping system, and a sole cropping of rocket with spacing between rows of 0.20 m. The statistical design adopted was the complete randomized block with four replicates. During winter, higher profitability was achieved with the highest population density. Highest profitability of the crops in both seasons was obtained in summer.

The Northeast region of Brazil has the second highest number of species of the Myrtaceae family. It is mostly covered by the Caatinga biome, which is very degraded, making it difficult to preserve species of this family. Thus, the objective of this work was to describe the seed, seedling, and fruit morphology, and seed germination of Psidium sobralianum Landrum & Proença plants of the São Francisco Valley, Brazil. The fruits were collected in an area of the Brazilian Agricultural Research Corporation (Embrapa Semiarid), in Petrolina PE, Brazil. The evaluations consisted of determinations of fruit shape, consistency, and number of seeds; seed form, cotyledons, hilum, hypocotyl-radicle axis, and embryo type; epicarp, mesocarp, endocarp, and seed staining; longitudinal, transversal, and ventral diameters of fruits and seeds; fruit, pulp, and seed fresh and dry masses; germination test; first count of germinated seeds; germination speed index; shoot and root lengths; shoot and root fresh and dry masses; and imbibition test. Psidium sobralianum has polyspermic, berry fruits, subclassified as solanidium, with persistent sepals and globular shape, consisting of epicarp, mesocarp, endocarp and seeds. The fruits have green with orange epicarp, pale-green mesocarp, and white endocarp. The seeds have a pilose and bony aspect, a pimentoid type of embryo, foliaceous cotyledons, presence of operculum and hilum, and pale-yellow tegument. The germination is epigeal phanerocotiledonar, with root protrusion from 26 days after sowing (DAS); it presents a short, glabrous, thick radicle, and a rounded, pale-green apex. The germination is slow, probably due to the mechanical barrier of the tegument, and stabilizes at 90 DAS.

ABSTRACT The objective of this study was to evaluate genetic divergence among cowpea genotypes and to select parents for crosses aimed at the fresh pod and grain market. Two experiments were carried out during 2014, corresponding to two sowing times, in the municipality of Mossoró, State of Rio Grande do Norte. Twenty-three cowpea genotypes were evaluated in a randomized complete block design with four replicates. Fifteen descriptors were used to quantify divergence, using the Mahalanobis distance as a measure of dissimilarity, obtained from the genotypic mean predicted by the Restricted Maximum Likelihood/Best Linear Unbiased Prediction (REML/BLUP) method. The Unweighted Pair Group Method with Arithmetic Mean (UPGMA) hierarchical method was used to group genotypes and the Singh criterion to quantify the contribution of traits to genetic divergence. The genotype × environment interaction (G × E) influenced divergence, both in the contribution of traits and in the grouping of genotypes. In the experiment 1, the genotypes were distributed among four groups. In the experiment 2, less discrimination occurred and the genotypes were represented by only two groups. When joint analysis of two evaluations was carried out based on two sowing times, genotypes were represented by six groups. The G × E interaction influences the contribution of traits and the grouping of cowpea genotypes in the study of divergence. The genetic divergence of the set of cowpea genotypes evaluated is mainly due to green grain and pod yield. BRS Aracê and BRS Xiquexique cultivars are the most divergent among the genotypes studied, representing 75% of the recommended crosses. | RESUMO O objetivo deste trabalho foi avaliar a divergência genética entre genótipos de feijão-caupi e selecionar genitores para cruzamentos visando o mercado de vagens e grãos verdes. Foram conduzidos dois experimentos, correspondendo a duas épocas de semeadura, no município de Mossoró, Rio Grande do Norte, ano 2014. Foram avaliados 23 genótipos de feijão-caupi em delineamento de blocos casualizados com quatro repetições. Foram utilizados 15 descritores para quantificar a divergência, utilizando como medida de dissimilaridade a distância de Mahalanobis, obtida a partir da média genotípica predita pelo método REML/BLUP. Utilizou-se o método hierárquico UPGMA para agrupar os genótipos e o critério de Singh para quantificar a contribuição dos caracteres para a divergência genética. A interação genótipos x ambientes influenciou a divergência, tanto na contribuição dos caracteres quanto no agrupamento dos genótipos. Na primeira época de cultivo os genótipos foram distribuídos em quatro grupos. Na segunda época ocorreu menor discriminação, sendo que os genótipos formaram apenas dois grupos. Ao realizar-se o agrupamento com base na análise conjunta das duas avaliações, realizadas nas duas épocas de semeadura os genótipos foram agrupados em seis grupos. A interação genótipos x ambientes influencia a contribuição das características e o agrupamento dos genótipos de feijão-caupi no estudo de divergência. A divergência genética do conjunto de genótipos de feijão-caupi avaliados é devida principalmente a produtividades de grãos verdes e de vagens verdes. As cultivares BRS Aracê e BRS Xiquexique foram os genótipos mais divergentes entre os estudados, fazendo parte de 75% dos cruzamentos recomendados.

ABSTRACT Cowpea bean is a socioeconomically important legume that contribute to generate employment and income. This species presents great grain variability, and the commercial subclass black eye stands out as a very appreciated grain in Brazil and abroad, thus requiring the development of new cultivars. The objective of this work was to evaluate and select lineages of commercial black eye cowpea, based on simultaneous, and direct selection. First, 105 progenies and four controls were evaluated using the Federer's augmented block design. Seventy-seven progenies, selected from this evaluation-first selection cycle-and four controls were evaluated in three environments, using a simple 9×9 lattice design. Based on this evaluation, the second selection cycle was possible, resulting in 24 progenies. The gain by direct selection was lower than the predicted gain for grain yield in the first cycle, indicating that the selection was not effective. This result was probably due to the reduced genetic variability caused by the selection pressure. In the second cycle, the predicted and observed gains were similar, indicating that much of the expected gain was observed. The predicted and observed gains, with simultaneous selection based on the rank sum selection index, were similar in the first and second cycle. The simultaneous and direct selections resulted in genetic gains for grain yield in the two selection cycles, making it possible the selection of high grain yield lineages. | RESUMO O feijão-caupi é uma leguminosa socioeconomicamente importante, contribuindo com a geração de emprego e renda. É uma espécie que apresenta grande variabilidade para o tipo de grão, sendo a subclasse comercial fradinho a que se destaca por ser um grão muito apreciado no Brasil e no exterior, demandando o desenvolvimento de novas cultivares. Este trabalho foi realizado com o objetivo de avaliar e selecionar linhagens de feijão-caupi tipo comercial fradinho, baseada na seleção simultânea e seleção direta. Inicialmente foram avaliadas 105 progênies e quatro testemunhas, utilizando o delineamento Blocos Aumentados de Federer. A partir desta avaliação foram selecionadas 77 progênies (primeiro ciclo de seleção), e quatro testemunhas que foram avaliadas em três ambientes, utilizando o delineamento látice simples 9x9. Fundamentado nessa avaliação, foi possível realizar o segundo ciclo de seleção, resultando em 24 progênies. Pela seleção direta, o ganho realizado foi inferior ao ganho predito para produtividade no primeiro ciclo, indicando que a seleção não foi efetiva, provavelmente devido à redução da variabilidade genética ocasionada pela pressão de seleção. No segundo ciclo, os ganhos realizado e predito foram bem próximos, indicando que grande parte do ganho esperado foi concretizado. Para os ganhos com a seleção simultânea baseados no Índice de Soma de Ranks, os valores de ganho predito e realizado foram semelhantes no primeiro e segundo ciclo. As seleções, simultânea e direta, possibilitaram a obtenção de ganhos genéticos para produtividade nos dois ciclos de seleção, possibilitando a seleção de linhagens de alta produtividade.

RESUMO O objetivo do trabalho foi avaliar o desempenho de linhagens elite de feijão-caupi de porte ereto e semiereto em ambientes de Mato Grosso e Minas Gerais. Os ensaios foram conduzidos em Jaíba, Janaúba e Sete Lagoas em Minas Gerais, e em Primavera do Leste e Nova Ubiratã em Mato Grosso. Foram avaliados 20 genótipos de feijão-caupi. Utilizou-se o delineamento de blocos casualizados, com quatro repetições. Os dados obtidos foram submetidos a análises de variância individuais e conjunta e as médias agrupadas pelo teste de Scott-Knott (P<0,05). Foram avaliados os caracteres porte da planta, acamamento, valor de cultivo, comprimento de vagem e rendimento de grãos. Nos ambientes do Mato Grosso, destacaram-se as linhagens MNC04-768F-21 e MNC04F-795F-168 como as mais produtivas e com características de porte da planta, acamamento e valor de cultivo semelhantes às da cultivar BRS Guariba. Nos ambientes de Minas Gerais, especialmente na região Norte do Estado, representada pelos ambientes de Jaíba e Janaúba, destacaram-se como mais produtivas as linhagens MNC04-769F-30, MNC05-795F-154, MNC04-769F-49 e a cultivar BRS Tumucumaque. Entretanto, as cultivares BRS Guariba, BRS Tumucumaque, BRS Novaera, BRS Itaim e BRS Cauamé, e as linhagens MNC04-792F-143 e MNC04-792F-144 apresentam produtividades satisfatórias e boas características de porte, acamamento e valor de cultivo, representando boas alternativas para recomendação de cultivo nesta região. | ABSTRACT The objective of this work was to evaluate the agronomic performance of erect and semi-erect cowpea elite lines grown in the States of Minas Gerais and Mato Grosso, Brazil. The experiments were conducted in Jaíba, Janaúba, Sete Lagoas (Minas Gerais), Primavera do Leste and Nova Ubiratã (Mato Grosso), with 20 genotypes of cowpea, arranged in a randomized block design with four replications. The data were subjected to individual and joint analyses of variance and means grouped by the Scott-Knott test (p<0.05). The plant growth habit, lodging, cultivation value, pod length and bean yield were evaluated. The lines MNC04-768F-21 and MNC04F-795F-168 had the highest bean yield in the experiments conducted in Mato Grosso, and their growth habit, lodging and cultivation value were similar to those of the cultivar BRS-Guariba. The lines MNC04-769F-30, MNC05-795F-154 and MNC04-769F-49 and the cultivar BRS-Tumucumaque had the highest bean yield in the experiments conducted in Minas Gerais. However, the cultivars BRS-Guariba, BRS-Tumucumaque, BRS-Novaera, BRS-Itaim and BRS-Cauamé and the lines MNC04-792F-143 and MNC04-792F-144 showed satisfactory bean yield and good growth habit, plant lodging and cultivation value in the State of Minas Gerais, especially in the northern region of the state (Jaíba and Janaúba), representing good alternatives for the genotypes recommended for this region.

RESUMO Em frutos climatéricos, como é o caso da manga, as perdas vão da colheita ao consumo. Tendo como controle a refrigeração e a modificação da atmosfera passivamente, com emprego de revestimentos comestíveis e biodegradáveis ou o acondicionamento em filmes plásticos. Objetivou-se avaliar a influência da cera de carnaúba e embalagem de filme plástico Xtend, utilizando ou não refrigeração na conservação pós-colheita de manga ‘Tommy Atkins’. Os frutos foram revestidos com solução de cera de carnaúba e/ou acondicionados nas embalagens Xtend e armazenados nas temperaturas de 25 ± 3 ºC e 12 ± 1 ºC, por 21 dias. A cada sete dias foram realizadas avaliações quanto à perda de massa, firmeza do fruto, sólidos solúveis totais, acidez total titulável e vitamina C dos frutos e concentração de CO2 nas embalagens. Verificou-se que o armazenamento refrigerado retardou a velocidade das reações de degradação, auxiliando na conservação de mangas ‘Tommy Atkins’. O revestimento dos frutos com cera de carnaúba e embalagem Xtend, sob refrigeração, possibilitou o seu armazenamento por 21 dias a 12 ± 1 ºC, reduzindo a concentração de CO2, a perda de massa e a diminuição da acidez dos frutos e preservando a firmeza. | ABSTRACT For climacteric fruits, such as mango, losses have been reported from harvest to fruit consumption. Thus, controlled refrigeration and passive modified atmosphere have been used in combination with edible and biodegradable coatings or plastic packaging to minimise these losses. The present study aimed to evaluate the influence of carnauba wax and Xtend plastic packaging film, with and without refrigerated storage, on the post-harvest preservation of 'Tommy Atkins' mangoes. The fruits were coated with carnauba wax and/or wrapped in Xtend bags and then stored at 12 ± 1 and 25 ± 3 °C for 21 days. The weight loss, fruit firmness, total soluble solids, titratable acidity, vitamin C content, and the CO2 concentration inside the package were determined at 7-day intervals. Cold storage was observed to slow down the rate of degradation and to reduce adverse degradation reactions. By coating the fruits with carnauba wax, packaging them with Xtend plastic and keeping them under refrigeration, it was possible to store the mangoes at 12 ± 1 °C for 21 days. In this way, the CO2 concentration was reduced, mass loss and acidity were decreased, and the fruit firmness was preserved.

ABSTRACT The objective of this work was to evaluate the biomass production and antioxidant enzymatic system activity of irrigated forage sorghum with saline aquaculture effluent under different leaching fractions. The experiment was conducted in the Caatinga Experimental Field of the Embrapa Semiarido, in Petrolina, State of Pernambuco, Brazil. The experimental design was a complete randomized block in a split-plot arrangement with four replications, consisting of three forage sorghum varieties (Volumax, F305 and Sudan) and four leaching fractions (0, 5, 10 and 15%). The vegetal materials were collected when the plants were at the soft-dough stage. The biomass production and activity of the enzymes superoxide dismutase, catalase and ascorbate peroxidase were evaluated. Irrigation with saline aquaculture effluent with leaching fraction of 15% results in low salinity level in the root zone and higher biomass production of forage sorghum Sudan and F305, in semiarid conditions. The antioxidant system was activated in the three sorghum varieties to prevent accumulation of reactive oxygen species, with the synchrony between the enzymes superoxide dismutase and catalase resulting in a better productive response of the varieties Sudan and F305. | RESUMO Objetivou-se com este trabalho avaliar o desempenho da cultura do sorgo forrageiro irrigado com efluente salino da piscicultura sob diferentes frações de lixiviação em relação à produção de biomassa e a atividade do sistema enzimático antioxidativo. O estudo foi realizado no Campo Experimental Caatinga, pertencente à Embrapa Semiárido, em Petrolina - PE. O delineamento experimental foi blocos ao acaso, com quatro repetições, em parcelas subdivididas, composto por três variedades de sorgo forrageiro (Volumax, F305 e Sudão) e quatro frações de lixiviação (0; 5; 10 e 15%). A coleta do material vegetal foi realizada quando os grãos da porção central da panícula apresentaram aspecto leitoso a pastoso. Foi avaliada a produção de biomassa e a atividade das enzimas superóxido dismutase, catalase e ascorbato peroxidase. O uso de 15 % de fração de lixiviação para irrigação com efluentes salinos da piscicultura proporciona um menor nível de salinidade da zona radicular e promove uma melhor produção de biomassa do sorgo forrageiro Sudão e F305 em condições semiáridas. O sistema antioxidativo foi ativado nas três variedades de sorgo para evitar o acúmulo de ROS, sendo a sincronia entre as enzimas superóxido dismutase e catalase que refletiu numa melhor resposta produtiva das variedades Sudão e F305.

RESUMO Tendo como objetivo responder ao questionamento de como o raleamento da cobertura vegetal de uma floresta tropical seca, caatinga, pode interferir no coeficiente de escoamento superficial, desenvolveu-se este estudo em três anos hidrológicos (2008, 2011 e 2013). O experimento foi conduzido no município de Iguatu no estado do Ceará, Brasil. No ano de 2008 a cobertura vegetal era caatinga em regeneração há 30 anos. A vegetação foi submetida ao manejo de raleamento em 2009, 2011 e 2013, eliminando-se as árvores com diâmetro inferior a 10 cm a altura do peito. Para investigar a resposta hidrológica em função da altura pluviométrica diária, tendo-se por base a distribuição de frequência acumulada, os eventos foram divididos em três classes pluviométricas (CP): CP ≤ 30 mm, 30 < CP ≤ 50 mm e CP > 50 mm. Para identificar se os coeficientes de escoamento gerados antes e após o raleamento da vegetação apresentavam diferenças significativas, aplicou-se o teste “t” de Student ao nível de 1%. Antes do raleamento (2008), a CP ≤ 30 mm registrou o maior percentual do coeficiente de escoamento diferindo estatisticamente ao nível de 1% de significância dos outros anos. Para eventos de grande magnitude (CP > 50 mm), os resultados apontam que o escoamento apresenta uma maior dependência das características da chuva e das condições de umidade do solo. O maior desenvolvimento do estrato herbáceo devido ao raleamento resultou em uma redução do fluxo do escoamento superficial. | ABSTRACT The objective of this work was to assess the effect of vegetation on the runoff coefficients of a Caatinga dry tropical forest before and after thinning. Thus, an experiment was conducted with evaluations in three hydrological years (2008, 2011 and 2013) in Iguatu, State of Ceará, Brazil. In 2008, the vegetation consisted of a 30-year regenerating Caatinga forest. The vegetation was subjected to thinning in 2009, 2011 and 2013, removing trees with less than 10-cm diameter at breast height. Hydrological responses were evaluated as a function of daily precipitation water depths, based on cumulative frequency distribution, by dividing precipitation events into three classes (CP) (CP≤30, 30<CP≤50 and CP>50 mm). Significant differences between runoff coefficients before and after vegetation thinning were assessed through the Student's t-test (p<0.01). Before thinning (2008), CP≤30 mm showed the highest runoff coefficient, differing statistically (p<0.01) from the other years. The results of precipitation events of great magnitude (CP>50 mm) indicate that the runoff is greatly dependent on rainfall characteristics and soil moisture conditions. The greater development of herbaceous vegetation due to thinning reduced the surface runoff.