Efficiency of maize cultivars in the absorption and use of nitrogen in a greenhouse environment<br>Eficiência de cultivares de milho na absorção e uso de nitrogênio em ambiente de casa de vegetação

The objectives of this study were to evaluate corn cultivars for efficiency in the absorption and use of nitrogen (N) levels of efficiency through the use of nitrogen in contrasting levels of this nutrient in the greenhouse. The experiment was carried out in a greenhouse and the experimental design was in randomized blocks, with 20 treatments and four replicates, in a 10 x 2 factorial arrangement. All 10 maize cultivars were represented by local varieties and commercial hybrids, and the applied N levels were 100 and 400 mg dm-3. Plots were represented by 8L pots containing 4 plants each, which were harvested in phenological stage V8. The evaluated characteristics were dry matter weight and N level of shoot and roots. The nutritional efficiency of cultivars was also evaluated. The studied cultivars had distinct characteristics concerning N use and absorption efficiency in environments of high and low nitrogen levels. The contrasting N levels allowed the occurrence of differences needed to distinguish the most efficient cultivars. Genotypes efficient for N use and responsive to its application can be selected based on the indexes used in this work. Os objetivos deste trabalho foram avaliar cultivares de milho quanto à eficiência na absorção e uso de nitrogênio (N) através de índices de eficiência de utilização de nitrogênio, em níveis contrastantes desse nutriente em ambiente de casa de vegetação. O experimento foi conduzido em casa de vegetação e o delineamento experimental utilizado foi o de blocos casualizados, com 20 tratamentos e quatro repetições, dispostos em um esquema fatorial de 10 x 2. As 10 cultivares de milho foram representadas por variedades locais e híbridos comerciais e as doses de N aplicadas foram de 100 e 400 mg dm-3. As parcelas foram representadas por vasos de 8 L, os quais continham 4 plantas por vaso, sendo colhidas no estádio fenológico V8. As características avaliadas foram o peso de matéria seca e teor de N da parte aérea e raízes. Também foi avaliada a eficiência nutricional das cultivares. As cultivares estudadas apresentaram características distintas quanto à eficiência no uso e absorção de N nos ambientes com alto e baixo nível de nitrogênio. Os níveis contrastantes de N utilizados permitiram que ocorressem diferenças necessárias para distinguir as cultivares mais eficientes. Genótipos eficientes para uso de N e responsivos a sua aplicação podem ser selecionados pelos índices utilizados nesse trabalho

ATRIBUTOS FÍSICOS E QUÍMICOS DE UM NEOSSOLO QUARTZARÊNICO SOB DIFERENTES SISTEMAS DE USO E MANEJO

The removal of the original vegetation and deployment of crops, combined with inadequate management practices, usually cause the deterioration of the physical and chemical quality of the soil. The aim of this study was to evaluate the changes in the physical and chemical attributes of a Typic Quartzipsamment from different land use systems and soil management. Four agroecosystems were selected: eucalyptus forest, extensive grazing, crop-livestock integration and integrated crop-livestock-forest, and an ecosystem preserved vegetation of native cerrado, located on Fazenda Modelo II in Ribas do Rio Pardo, MS. Soil samples were col-lected at depths of 0-5, 5-10 and 10-20 cm in a completely randomized design, with six plots of 150 m2 on each system. The integrated crop-livestock and integrated crop-livestock-forest provided the biggest contribution in the improvement of soil fertility. There was an antagonistic relationship between physical and chemical soil as sustainability evaluation, and chemical attributes had to be more affected than physical

Respostas morfofisiológicas entre procedências de canafístula submetidas a diferentes condições hídricas e nutricionais

This study aimed to evaluate morphological and physiological characteristics of different canafistula progenies (Peltophorum dubium) under different soil water and nutrient availability. The experiment was conducted in greenhouse, under completely randomized design with 12 treatments and four replications, in a factorial scheme 3 (provenance) x 2 (fertilization) x 2 (irrigation). Plant height, stem diameter and SPAD index (soil plant analysis development) were collected throughout the experiment every 15 days. At the end of the experiment, we determined shoot, root and total dry weight, ratio of shoot and root dry matter, leaf water potential and Dickson quality index. Provenances from Serra da Bodoquena and Serra de Maracaju had greater ability to resist water and nutritional stress in relation to Ivinhema, MS provenance. Differences among provenances were intensified when canafistula seedlings were not under water deficit. Water stress imposed on canafistula seedlings causes more morphophysiological damage than stress from lack of nutrients.O objetivo desse trabalho foi avaliar características morfofisiológicas entre diferentes procedências de canafístula (Peltophorum dubium) submetidas a ambientes distintos quanto à disponibilidade de água e nutrientes no solo. O experimento foi conduzido em casa de vegetação, em delineamento experimental inteiramente casualizado, com 12 tratamentos e quatro repetições, dispostos em esquema fatorial 3 (procedências) x 2 (adubações) x 2 (irrigações). Foram coletados dados de altura de plantas, diâmetro do colo e índice SPAD (soil plant analysis development) ao longo do experimento em intervalos de 15 dias. Ao final do experimento foi aferido o peso da matéria seca da parte aérea, de raízes e total, quociente entre matéria seca de parte aérea e matéria seca de raízes, potencial hídrico foliar e índice de qualidade de Dickson. As progênies oriundas da Serra da Bodoquena e Serra de Maracaju demonstraram maior capacidade de resistir ao estresse hídrico e nutricional em relação às progênies da região de Ivinhema, MS. As diferenças entre procedências são intensificadas em ambientes que não proporcionam déficit hídrico para as mudas de canafístula. O estresse hídrico imposto às plantas de canafístula causa mais danos morfofisiológicos do que o estresse por falta de nutrientes

Luminosidade, ácido indolbutírico e comprimentos de miniestacas na propagação de Peltophorum dubium (Sprengel) Taubert

The need for recovering degraded lands and the increased demand for forest products have been raising interest on Brazilian plant species and forest plantation technology. We aimed to evaluate the influence of mini-cutting length, indole-3-butyric acid (IBA) concentration and different environments on the propagation of copperpod (Peltophorum dubium). The experiment was conducted in a mini clonal garden at the Silviculture sector of FCA/UFGD. We tested: (1) four mini-cutting lengths (3.0; 4.5; 6.0; and 7.5 cm) in the absence and presence of 2,000 mg L-1 IBA for 100 days; and (2) two environments (shade and full sun) with three doses of IBA (0; 3,000; and 6,000 mg L-1) for 80 days. We evaluated stem diameter, number of leaves, fresh and dry weight of roots and shoots, weight of total fresh and dry matter, shoot length, and the Dickson quality index. Data was subjected to analysis of variance and quantitative means were evaluated by regression while qualitative variables were compared by Tukey’s test, both at 5% probability. According to the studied parameters of plantlet production, we observed that mini-cuttings 7.5 cm long are the most suitable for vegetative propagation of copperpod, with no need for exogenous application of IBA. Mini-cuttings 6.0 cm long yield plantlets with higher values of the evaluated quality parameters when cultivated in full sun and with exogenous application of 6,000 mg L-1 IBA.A atual necessidade de recuperação de áreas degradadas e a demanda por produtos de origem florestal têm aumentado o interesse sobre as espécies brasileiras e tecnologias de plantios florestais. Entretanto pouco se conhece sobre a propagação vegetativa em espécies florestais nativas. Assim, o trabalho objetivou avaliar diferentes comprimentos de miniestacas, ambientes e concentrações de AIB em canafístula (Peltophorum dubium). A implantação do minijardim clonal foi conduzida no viveiro de mudas do setor de Silvicultura da FCA/UFGD. Foram estudadas quatro alturas de miniestacas (3,0; 4,5; 6,0 e 7,5 cm) na ausência e presença de AIB (2.000 mg L-1), assim como dois ambientes (sombreado e pleno sol) em três doses desse hormônio (0; 3.000 e 6.000 mg L-1). Foram avaliadas a altura da parte aérea, diâmetro do coleto, número de folhas, peso da matéria seca da parte aérea e sistema radicular, matéria seca total, as relações entre essas variáveis e o índice de qualidade de Dickson. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste Tukey, a 5 % de probabilidade. A partir dos resultados obtidos, conclui-se que: entre os tamanhos de miniestacas, as de comprimento 7,5 cm são as mais indicadas para a propagação vegetativa de canafístula, independente da ausência ou presença de AIB; quanto menor o tamanho das miniestacas, maior a necessidade de hormônio para promoção do enraizamento; para miniestacas de 6,0 cm, o ambiente a pleno sol e a aplicação exógena de 6.000 mg L-1 de AIB proporcionam melhores parâmetros de qualidade de mudas

In vitro pollen viability of maize cultivars at different times of collection

ABSTRACT: In the present study, we aimed to assess the in vitro viability of pollen grains from maize cultivars collected at different times and days in the field. Four cultivars (Sol da Manhã, XB 6012, XB 8010, and BRS 2020) were evaluated from the second to fifth day of anthesis in three times. Pollen samples were evaluated for their in vitro viability through standard germination test in liquid and solid media and tetrazolium staining. The experimental design was completely randomized, in 4x4x3 split-split plots with four replicates. Data were subjected to analysis of variance followed by a means clustering test and linear regression analysis. The average percentage of viable pollen varied according to the day, collection time, and cultivar. In general, XB 8010 and BRS 2020 had the highest frequency of viable pollen. The highest percentages of viable pollen were observed on the second day of anthesis at 10:00h