Scielo RSS <![CDATA[Bragantia]]> vol. 75 num. 3 lang. pt <![CDATA[SciELO Logo]]> <![CDATA[Relações lineares entre caracteres de linho]]> RESUMO Os objetivos deste trabalho foram avaliar as relações lineares entre caracteres de linho (Linum usitatissimum L.) e identificar caracteres para a seleção indireta. Em área experimental de 15 × 15 m (225 m2), aos 134 dias após a semeadura, foram selecionadas, aleatoriamente, 300 plantas. Em cada planta, foram mensurados os caracteres altura de planta, número de ramos, número de cápsulas, massa verde de cápsulas, massa verde de parte aérea sem cápsulas, massa verde de parte aérea, massa seca de cápsulas, massa seca de parte aérea sem cápsulas e massa seca de parte aérea. Para cada caractere, foi calculada a média e o coeficiente de variação. Foi investigada a relação linear entre os caracteres por meio de análises de correlação e de trilha. Na cultura de linho, o número de cápsulas tem relação linear positiva com as massas verde e seca de cápsulas e de parte aérea e pode ser utilizado para seleção indireta.<hr/>ABSTRACT The objectives of this study were to evaluate the linear relations among traits of flax (Linum usitatissimum L.) and identify traits for indirect selection. In experimental area of 15 × 15 m (225 m2) 300 plants were randomly collected at 134 days after seeding. The traits plant height, number of branches, number of capsules, fresh matter of capsules, fresh matter of aerial part without capsules, fresh matter of aerial part, dry matter of capsules, dry matter of aerial part without capsules, and dry matter of aerial part were measured in each plant. The mean and coefficient of variation were calculated for each trait. It was studied the linear relation among the traits through correlation and path analysis. In flax, the number of capsules has positive linear relation with fresh and dry matter of capsules and aerial part and it can be used for indirect selection. <![CDATA[A classification proposal for coefficients of variation in <em>Eucalyptus</em> experiments involving survival, growth and wood quality variables]]> ABSTRACT The objective of this study was to present a classification proposal for coefficients of variation (CV) in Eucalyptus experiments, aiming at providing a useful tool for experiments involving growth, survival and wood quality traits. Ninety-four studies were selected from a search for peer-reviewed journals yielding a total of 508 data. The CVs were classified as low, moderate, high and very high. The mean, standard deviation, maximum and minimum values, skewness and kurtosis were estimated to describe the distribution shape. The Shapiro-Wilk test confirmed that all variables satisfied the assumption of normality (p &lt; 0.05). The results indicated that the growth traits had the highest variability, being variables strongly affected by the environment. In contrast, all variables related to wood quality (except extractives) had the lowest range of CVs. In summary, the classification proposed in this report provides a useful tool for researchers interested in estimating the accuracy of their experiments. <![CDATA[Fenotipagem de alta eficiência para vitamina A em banana utilizando redes neurais artificiais e dados colorimétricos]]> ABSTRACT Banana is one of the most consumed fruits in Brazil and an important source of minerals, vitamins and carbohydrates for human diet. The characterization of banana superior genotypes allows identifying those with nutritional quality for cultivation and to integrate genetic improvement programs. However, identification and quantification of the provitamin carotenoids are hampered by the instruments and reagents cost for chemical analyzes, and it may become unworkable if the number of samples to be analyzed is high. Thus, the objective was to verify the potential of indirect phenotyping of the vitamin A content in banana through artificial neural networks (ANNs) using colorimetric data. Fifteen banana cultivars with four replications were evaluated, totaling 60 samples. For each sample, colorimetric data were obtained and the vitamin A content was estimated in the ripe banana pulp. For the prediction of the vitamin A content by colorimetric data, multilayer perceptron ANNs were used. Ten network architectures were tested with a single hidden layer. The network selected by the best fit (least mean square error) had four neurons in the hidden layer, enabling high efficiency in prediction of vitamin A (r2 = 0.98). The colorimetric parameters a* and Hue angle were the most important in this study. High-scale indirect phenotyping of vitamin A by ANNs on banana pulp is possible and feasible.<hr/>RESUMO A banana é uma das frutas mais consumidas no Brasil, sendo importante fonte de minerais, vitaminas e carboidratos na dieta humana. A caracterização de genótipos superiores de banana permite identificar aqueles com qualidade nutricional para cultivo e para integrar programas de melhoramento genético. Porém, a identificação e quantificação dos carotenoides provitamínicos são dificultadas pelo custo instrumental e dos reagentes químicos para as análises, podendo se tornar inviável caso o número de amostras a serem analisadas seja elevado. Assim, objetivou-se verificar o potencial da fenotipagem indireta do teor de vitamina A em banana por redes neurais artificiais (RNAs) utilizando-se dados colorimétricos. Foram avaliadas 15 cultivares de bananeira com quatro repetições, totalizando 60 amostras. Para cada amostra, foram obtidos dados colorimétricos, estimando-se o teor de vitamina A na polpa dos frutos maduros. Para a predição do teor de vitamina A por dados colorimétricos, utilizaram-se RNAs do tipo perceptron multicamadas. Foram testadas dez arquiteturas de rede com uma única camada intermediária. A rede selecionada pelo melhor ajuste (menor erro quadrático médio) teve quatro neurônios na camada intermediária, possibilitando alta eficiência na predição de vitamina A (r2 = 0,98). Os parâmetros colorimétricos a* e ângulo Hue foram os mais importantes neste estudo. A fenotipagem indireta em alta escala da vitamina A por meio de RNAs na polpa de banana é possível e viável. <![CDATA[Potential of calcium silicate to mitigate water deficiency in maize]]> ABSTRACT The aim of this study was to evaluate the potential of calcium silicate to mitigate the effects of water deficiency in maize plants yield. A completely randomized factorial design, consisting of five combinations of calcium silicate (0, 25, 50, 75, and 100%) and five different soil moisture levels (30, 70, 100, 130, and 160%), was adopted. The following parameters were evaluated: soil matric potential, xylem water potential, silicon concentration, leaf dry weight, and dry mass production. Matric potential monitoring confirmed that the irrigation depths employed resulted in different environments for maize plant development during the experiment. Confirming the hypothesis of the study, at the lower irrigation depths, the maize production has accompanied the increase in calcium silicate used as corrective up to the proportion of 50%. These results indicate that silicon mitigated the impact of water deficiency in maize plants and increased the xylem water potential. <![CDATA[Effect of copper carbonate and zinc oxide applied to seeds on copper and zinc uptake by maize seedlings]]> ABSTRACT Seed treatment is an interesting alternative to deliver micronutrients to field crops. The aim of this study was to investigate the uptake of Cu and Zn by maize seedlings, with the application of the water-insoluble sources copper carbonate and zinc oxide as seed treatment. Treatments were composed of a control (untreated seeds), five doses of copper (0.14, 0.28, 0.56, 1.12 and 2.24 mg Cu∙seed–1) and zinc (0.55, 1.10, 2.20, 4.40 and 8.80 mg Zn∙seed–1) as well as five doses of copper and zinc combined (0.14, 0.28, 0.56, 1.12 and 2.24 mg Cu∙seed–1; 0.55, 1.10, 2.20, 4.40 and 8.80 mg Zn∙seed–1). Plants were cultivated in sand, under greenhouse conditions and, at the two-leaf stage (15 days), the root and shoot tissues dry mass and concentration of Cu and Zn were determined, which allowed to calculate accumulation and uptake efficiency of these micronutrients by maize plants. Seed treatment with copper carbonate and zinc oxide increased both root and shoot concentration and accumulation of Cu and Zn in maize seedlings, with two fully expanded leaves. Cu tended to accumulate in roots, while Zn was more evenly distributed among roots and shoots. Combined application of copper carbonate and zinc oxide resulted in lower uptake of both Cu and Zn by maize if compared to individual applications, with Cu uptake reduced in a higher extent. <![CDATA[Crambe affected by biological and chemical seed treatments]]> ABSTRACT Crambe has great potential for cultivation in tropical regions, but its biotic factors may be a limiting aspect for its production. Thus, we aimed in this study to assess the effect of pre‐sowing seed treatments on seedling emergence, root system, production components, and oil. The experiment was conducted during two years in Cascavel, Paraná, Brazil. The experimental design consisted of randomized blocks with six treatments, including a control treatment (no treatment), biological treatments (Trichoderma asperellum and Bacillus subtilis), and chemical treatments (glutamic acid, thiamethoxam and zinc), with four replications. Emergence and growth crambe, as well as production components and oil in the first year were higher due to the contrast in the agricultural years. In the first year, the chemical treatment with thiamethoxam stood out for emergency of plants. Seed treatments did not influence the growth of the aerial parts of the plants, but provided an increase in the root system, especially zinc. Biological (T. asperellum and B. subtilis) and chemical (thiamethoxam) seed treatments led to higher crambe yield when compared to the control treatment; however, the biological treatment with T. asperellum provided less oil. <![CDATA[Adaptabilidade e estabilidade de genótipos de feijão caupi ereto via REML/BLUP e GGE Biplot]]> ABSTRACT The objective of this study was to investigate the association between the GGE Biplot and REML/BLUP methods and select cowpea genotypes that meet simultaneously high grain yield, adaptability and stability in the Mato Grosso do Sul environments. The experiments were carried out from February to July 2010, 2011 and 2012 in the municipalities of Dourados, Aquidauana and Chapadão do Sul. The experiments in Chapadão do Sul were conducted only in the years of 2010 and 2011, totaling eight environments. After detecting significant genotypes × environments (GE) interaction, the adaptability and the phenotypic stability of cowpea genotypes were analyzed by GGE Biplot and REML/BLUP methods. These methods were concordant in the identification of the best cowpea genotypes for the State of Mato Grosso do Sul. The BRS- Tumucumaque and BRS-Guariba cultivars are the closest to the ideal in terms of high grain yield and phenotypic stability, being suitable for cultivation in the State.<hr/>RESUMO O objetivo deste trabalho foi verificar a associação entre os métodos GGE Biplot e REML/BLUP e selecionar genótipos de feijão-caupi que reúnam simultaneamente alta produtividade de grãos, adaptabilidade e estabilidade nos ambientes de Mato Grosso do Sul. Os experimentos foram realizados no período de Fevereiro a Julho de 2010, 2011 e 2012, nos municípios de Dourados, Aquidauana e Chapadão do Sul. Os experimentos em Chapadão do Sul foram realizados apenas nos anos de 2010 e 2011, totalizando oito ambientes. Depois de detectar a interação genótipos × ambientes (GE) significativa, a adaptabilidade e a estabilidade fenotípica dos genótipos de feijão-caupi foram analisadas pelos métodos GGE Biplot e REML/BLUP. Esses métodos foram concordantes na identificação dos melhores genótipos de feijão-caupi para o Estado de Mato Grosso do Sul. As cultivares BRS-Tumucumaque e BRS-Guariba são as mais próximas do ideal em termos de alta produtividade de grãos e estabilidade fenotípica, sendo então indicadas para o cultivo no Estado. <![CDATA[Variabilidade genética e homozigose em uma população F4 de mamoneira por meio de marcadores microssatélites]]> ABSTRACT The objectives of this study were to identify the genetic variability and estimate the level of homozygosity in a castor bean F4 population using microsatellite markers (SSR). To this end, it was performed the genotyping of the population through 53 pairs of SSR primers. Allele frequencies were estimated by number of alleles per locus, expected heterozygosity (He), observed heterozygosity (Ho) and polymorphic information content (PIC). An array of genetic dissimilarity was generated by Nei and Li index, and hierarchical cluster analysis was performed using the Unweighted Pair-Group Method Averages (UPGMA) method. Polymorphism was detected in a total of eight loci (15.09%) of the 53 evaluated, with the presence of two alleles per locus. Allele frequencies varied between 0.71 and 0.53, and the PIC, between 0.32 and 0.37. The average observed heterozygosity Ho (0.30) was lower than the expected heterozygosity He (0.47). Five dissimilar groups were formed, showing that there is genetic variability among the evaluated genotypes. The highest genetic dissimilarity was 0.708 and the lowest, 0.00. The percentages of homozygous genotypes varied from 25 to 75%. These results show that controlled selfing in castor bean raises the level of homozygosity, important for the breeding program.<hr/>RESUMO Os objetivos deste trabalho foram identificar a variabilidade genética e estimar o nível de homozigose em uma população F4 de mamoneira usando marcadores microssatélites (SSR). Para tanto, foi realizada a genotipagem da população por meio de 53 pares de iniciadores SSR, e as frequências alélicas, número de alelos por loco, heterozigosidade esperada (He), heterozigosidade observada (Ho) e conteúdo informativo de polimorfismo (PIC) foram estimados. Uma matriz de dissimilaridade genética foi gerada pelo índice de Nei e Li, e a análise de agrupamento hierárquico foi realizada por meio do método Unweighted Pair-Group Method Averages (UPGMA). Foi detectado polimorfismo em um total de oito loci (15,09%) dos 53 avaliados, com presença de dois alelos por loco. As frequências alélicas variaram entre 0,71 e 0,53, e o PIC, entre 0,32 e 0,37. A heterozigosidade média observada Ho (0,30) foi menor que a heterozigosidade esperada He (0,47). Houve formação de cinco grupos dissimilares, mostrando que há variabilidade genética entre os genótipos avaliados. A maior dissimilaridade genética foi de 0,708 e a menor, de 0,00. As porcentagens de homozigose entre os genótipos variaram de 25 a 75%. Esses resultados mostram que a autofecundação controlada em mamoneira eleva o nível de homozigose, importante para o programa de melhoramento genético. <![CDATA[Uso da metodologia REML/BLUP para seleção de genótipos de algodoeiro com maior adaptabilidade e estabilidade produtiva]]> RESUMO A metodologia máxima verossimilhança restrita/melhor preditor linear não viesado (REML/BLUP) tem sido utilizada para interpretação da estabilidade genotípica e da adaptabilidade de culturas como feijão, canade-açúcar, cajueiro, eucalipto e arroz, porém pesquisas com o algodão ainda são limitadas. O objetivo deste trabalho foi selecionar genótipos de algodoeiro, via modelos mistos, que reúnem simultaneamente adaptabilidade e estabilidade produtiva e verificar se essa metodologia pode ser utilizada nos programas de melhoramento genético do algodoeiro. Foram avaliadas 36 linhagens em três ensaios localizados em Apodi, RN (2013 e 2014), e Santa Helena, GO (2013), em delineamento de blocos casualizados com duas repetições. Os parâmetros genéticos foram estimados pela metodologia REML/BLUP, e a seleção baseou-se no método da média harmônica da performance relativa dos valores genéticos (MHPRVG), com três estratégias: seleção com base no valor genético predito, tendo-se considerado o desempenho médio dos genótipos em todos os ambientes (sem efeito de interação); o desempenho em cada ambiente (com efeito da interação); e seleção simultânea quanto à produtividade de algodão em caroço, adaptabilidade e estabilidade. Os genótipos CNPA 2012-60 e CNPA 2012-65 podem ser cultivados em ambientes similares aos testados, pois reúnem alta adaptabilidade e estabilidade produtiva de algodão em caroço. Houve concordância entre as estatísticas utilizadas na discriminação dos genótipos mais produtivos e com alta adaptabilidade e estabilidade, o que indica que as mesmas podem fazer parte de critérios seletivos na rotina dos programas de melhoramento do algodoeiro.<hr/>ABSTRACT The restricted maximum likelihood/best linear unbiased predictor methodology (REML/BLUP) has been used for the interpretation of genotypic stability and adaptability of crops such as common bean, sugarcane, cashew, eucalyptus and rice, but researches with cotton are still limited. The aim of this work was to select cotton genotypes, via mixed models, which simultaneously meet adaptability and stability and verify if this methodology can be used in genetic improvement programs in cotton. Thirty-six strains were evaluated in three trials located in Apodi, Rio Grande do Norte (2013 and 2014), and Santa Helena, Goiás (2013), in a randomized block design with two replications. The genetic parameters were estimated by REML/ BLUP methodology, and the selection was based on the method of the harmonic mean of the relative performance of the genetic values (MHPRVG), with three strategies: selection based on the predicted genetic value, considering the average performance of genotypes in all environments (without interaction effect); performance in each environment (with interaction effect); and simultaneous selection as to cotton yield, stability and adaptability. The CNPA 2012-60 and CNPA 2012-65 genotypes may be grown in environments similar to those tested, since they present high adaptability and productive stability of cotton. There was agreement among the statistics used in discrimination of the most productive genotypes with high adaptability and stability, indicating that they can be part of selective criteria in the routine of cotton breeding programs. <![CDATA[Efeito do extrato etanólico de sementes de <em>Annona mucosa</em> no desenvolvimento e comportamento alimentar de <em>Spodoptera frugiperda</em>]]> RESUMO No Brasil, a lagarta-do-cartucho Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) é uma praga importante do milho e de outras espécies cultivadas, incluindo cultivos hortícolas, soja, arroz e algodão. Inseticidas botânicos são considerados uma opção interessante para o manejo de S. frugiperda, especialmente em sistemas de produção orgânica, e derivados de Annonaceae constituem uma fonte promissora destes. Diante desse potencial, o efeito do extrato etanólico de sementes de Annona mucosa — ESAM (Annonaceae) no desenvolvimento e comportamento alimentar de S. frugiperda foi avaliado através de bioensaios de exposição em meio artificial (ingestão). ESAM reduziu a viabilidade das fases larval e pupal e o peso de pupa bem como provocou um aumento na duração da fase larval de S. frugiperda. Além disso, ESAM também causou um aumento na proporção de pupas e adultos com alterações morfológicas. Entretanto, ESAM não causou efeito deterrente de alimentação para lagartas de quarto ínstar de S. frugiperda, embora esse extrato tenha ocasionado um decréscimo significativo no consumo ao longo do tempo (toxicidade pós-ingestão).<hr/>ABSTRACT In Brazil, the fall armyworm Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is an important pest of maize and other crops including horticultural crops, soybean, rice, and cotton. Botanical insecticides are an interesting option for S. frugiperda management especially in organic production systems, and annonaceous derivatives have been considered a promising source of them. In light of this potential, we investigated the antifeedant and growth inhibitory effects of ethanolic extract from Annona mucosa seeds — ESAM (Annonaceae) against S. frugiperda using dietary exposure bioassays. ESAM decreased larval and pupal viabilities and also the pupal weight as well as increased the larval phase duration of S. frugiperda. Moreover, ESAM also caused an increase in the proportion of pupae and adults with morphological changes. However, ESAM did not cause antifeedant effect for 4-instar S. frugiperda larvae, though it decreased consumption throughout the time (post-ingestive toxicity). <![CDATA[First record and characteristics of damage caused by the spider mite <em>Tetranychus neocaledonicus</em> André on peanuts in the State of Paraíba, Brazil]]> ABSTRACT The red spider mite Tetranychus neocaledonicus André (Acari: Tetranychidae) is commonly found on cotton and castor bean in Brazil, especially in the northeast, but to date it had not been found damaging cultivated peanut. The objective of this research was to record the occurrence of this mite on peanut plants and describe its damage on this Fabaceae. The peanut plants, when infested by this mite, exhibit initially small whitish spots on the leaves, which quickly develop to chlorotic spots, followed by silvering, drying and fall because of their feeding. The severity of the damage caused to peanut and the adaptability of the mite to warm and dry conditions indicate that this species has potential as peanut pest in northeastern Brazil. <![CDATA[Teor de nutrientes e viabilidade da bananicultura em Cambissolos com diferentes profundidades]]> RESUMO No nordeste brasileiro, a bananicultura é praticada em locais onde há solos de profundidade variável. A dinâmica da água em solos mais profundos pode alterar minerais herdados diretamente da rocha e aumentar a disponibilidade de nutrientes. Neste estudo, objetivou-se avaliar o teor de nutrientes em Cambissolos raso e profundo, bem como o estado nutricional e a produtividade de bananeiras cultivadas nesses solos. Para a fertilidade do solo, foi utilizado o delineamento em parcelas subdivididas com dois tratamentos nas parcelas principais (solos raso e profundo) e seis tratamentos nas subparcelas (profundidades de coleta: 0 – 10, 10 – 20, 20 – 30, 30 – 40, 40 – 50 e 50 – 60 cm). Para avaliar o estado nutricional e a produtividade da cultura, foram considerados dois fatores de tratamento (solos raso e profundo) e 30 repetições. Foram determinadas as concentrações de macro e micronutrientes no solo e no tecido vegetal, outros atributos químicos do solo para avaliação da fertilidade e a produção de frutos. O solo profundo apresentou maiores valores de fósforo (P), potássio (K), sódio (Na), cobre (Cu), ferro (Fe), manganês (Mn), acidez potencial (H + Al), matéria orgânica (MO) e porcentagem de sódio trocável (PST). Teores de MO, valores de soma de bases (SB), saturação por bases (V%), Fe e Mn foram maiores na superfície dos solos. O estado nutricional das bananeiras foi favorecido no solo profundo, principalmente quanto às concentrações de nitrogênio (N), P, K, boro (B), Cu e Mn. Isso levou ao maior peso de cachos e à maior produtividade no solo mais profundo.<hr/>ABSTRACT In the Brazilian Northeastern region, banana cropping occurs in sites where there are soils presenting variable depths. The water dynamics in deeper soils may change minerals directly inherited from rock and increase nutrients availability. In this study, the aim was to evaluate the nutrient contents in shallow and deep Cambisols, as well as the nutritional status and yield of banana plants cropped in these soils. In order to study soil fertility, it was used the split plot design with two treatments in the main plots (shallow and deep soils) and six treatments in the subplots (soil sampling depths: 0 – 10, 10 – 20, 20 – 30, 30 – 40, 40 – 50 and 50 – 60 cm). In order to evaluate the nutritional status and crop yield, two treatment factors were assumed (shallow and deep soils) and 30 replicates. The concentrations of macro and micronutrients in both soil and plant tissue were determined, as well as other chemical attributes of soil for fertility evaluation, and fruit yield. The deep soil presented higher values of phosphorus (P), potassium (K), sodium (Na), copper (Cu), iron (Fe), manganese (Mn), potential acidity (H + Al), organic matter (OM) and exchangeable sodium percentage (PST). Organic matter, sum of bases (SB), bases saturation (V%), Fe, and Mn were higher in the soil surface. The nutritional status of banana plants was favored in the deep soil, mainly regarding contents of nitrogen (N), P, K, boron (B), Cu, and Mn. It resulted in higher weight of bunches and higher yield in the deeper soil. <![CDATA[Substrates and containers for the development of <em>Brassica pekinensis</em> L. seedlings]]> ABSTRACT The aim of this study was to evaluate the development of Chinguensai (Brassica pekinensis L.) seedlings, under different formulations of substrates and sizes of containers, in Fortaleza, Ceará. For this, two studies were conducted in factorial design with randomized blocks and four replicates. The first study was conducted in a factorial (4 × 4) design. Four substrate formulations (powder-type coconut fiber; carbonized rice hull and earthworm casting) had the following proportions: S1 (1:1:1); S2 (0:1:1); S3 (1:0:1); and S4 (0:0:1) by volume basis (v/v) and four evaluation dates (22, 27, 34 and 41 days after sowing — DAS). The second study was conducted in a factorial (3 × 4) design with three types of containers with different cell volumes (31, 18 and 11 cm3) and four evaluation dates (22, 27, 34 and 41 DAS). The fresh and dry weight of the shoot and root systems was evaluated. Both studies showed no interaction between the variables, with differences noted for substrate factors, containers and times in all traits. In the first study, the earthworm compost resulted in the highest yield of fresh and dry seedling weight. In the second study, the container with 31 cm3 of cell volume showed the highest production of fresh and dry weights. The results showed that the substrate composed solely of earthworm humus and with the use of trays with 31 cm3 of cell volume provided seedlings of Chinguensai with the optimal production for transplanting 41 DAS. <![CDATA[Eficiência de uso do Nitrogênio em cultivares modernas de trigo]]> ABSTRACT The nitrogen use efficiency (NUE) is defined as the capacity of a given genotype in take advantage of the applied nitrogen (N) and transform it in biomass and grains. The objective of this study was to evaluate 12 wheat cultivars as to the NUE and its components. The experiment was conducted in a controlled environment, in a randomized block design with three replications. Twelve wheat cultivars were submitted to four N supply levels (0, 80, 160 and 240 kg of N∙ha–1). The data were submitted to analysis of variance, means multiple comparison, polynomial regression, and path analysis. The nitrogen remobilization efficiency (NRE) was the main NUE component of the evaluated cultivars, in both low and high conditions of nitrogen fertilization. In the cultivars average, the nitrogen utilization efficiency (NUtE) presented reduction tendency as the N supply was increased, tending to stabilization at the dose of 231 kg of N∙ha–1. The wheat cultivars Mirante, TBIO Itaipu, BRS Parrudo, and TBIO Iguaçu were the most efficient on the N use, and the first two were also efficient in remobilizing the N from the phytomass to the grains.<hr/>RESUMO A eficiência de uso do Nitrogênio (EUN) é definida como a capacidade de determinado genótipo em aproveitar o Nitrogênio (N) aplicado e transformá-lo em fitomassa e grãos. O objetivo deste estudo foi avaliar 12 cultivares de trigo quanto à EUN e seus componentes. O experimento foi conduzido em ambiente controlado, em delineamento de blocos ao acaso, com três repetições. Doze cultivares de trigo foram submetidas a diferentes doses de N (0, 80, 160 e 240 kg de N∙ha–1). Os dados foram submetidos a análise de variância, comparação múltipla de médias, regressão polinomial e análise de trilha. A eficiência de remobilização do Nitrogênio (ERN) foi o principal componente da EUN das cultivares avaliadas, tanto na condição de baixa quanto na de alta oferta de adubação nitrogenada. Na média das cultivares, a eficiência de utilização do Nitrogênio (EUtN) apresentou tendência de redução à medida que se elevou a oferta de N, tendendo à estabilização na dose de 231 kg de N∙ha–1. As cultivares de trigo Mirante, TBIO Itaipu, BRS Parrudo e TBIO Iguaçu foram as mais eficientes no uso do N, e as duas primeiras também foram eficientes em remobilizar o N da fitomassa para os grãos. <![CDATA[Plant density and mineral nitrogen fertilization influencing yield, yield components and concentration of oil and protein in soybean grains]]> ABSTRACT There are few studies on the interaction between soybean plant density and nitrogen fertilization. This research aimed to assess the effect of mineral nitrogen associated to different plant densities on yield, yield components and oil and protein concentrations of soybean grains. Two experiments were conducted in the 2013/2014 and 2014/2015 growing seasons, with randomized complete block design, in a split plots scheme, with six replications. Four sowing densities (150, 300, 440 and 560 thousand viable seeds∙ha–1) were allocated in the plots, and two nitrogen levels (0 and 45 kg N∙ha–1, applied at V2, using ammonium sulfate) were allocated in the subplots. There was no interaction between soybean plant density and the application of mineral nitrogen on yield, yield components and oil and protein concentrations in soybean grains. Higher plant population reduced the number of pods per plant and the contribution of branch sinks to the grain yield, but the effects on yield differed among the growing seasons. The mineral nitrogen fertilization did not increase yield and protein and oil concentrations in the grains, thus it was unnecessary. <![CDATA[Light spectrum on the quality of fruits of physalis species in subtropical area]]> ABSTRACT The aim of this study was to analyze the effect of colored-shade nets on the physicochemical characteristics of physalis in subtropical area. The experimental design was the randomized blocks with a 4 × 5 factorial, being four species of physalis (Physalis peruviana, P. pubescens, P. minima and P. ixocarpa) and four net colors (white, blue, red and black), besides the control under full sun. Titratable acidity (TA), pH, vitamin C, soluble solids (SS), SS/TA relation, total phenolics, anthocyanins and antioxidant capacity were evaluated. It was observed that P. peruviana and P. pubescens have more acid fruits, and P. minima shows vitamin C content higher than the other species. In general, fruits of P. peruviana and P. pubescens have better quality when grown in white, blue or black shade net; fruits of P. minima are physicochemically superior when produced under full sun or under white or blue shade net; finally, fruits of P. ixocarpa have low quality when produced under black net.