Belém, Brazil
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Pereira F.B.,Engenheiro Agronomo | DoVale J.C.,Federal University of Tocantins | Carneiro P.C.S.,Federal University of Viçosa | Fritsche-Neto R.,Federal University of Viçosa
Revista Ceres | Year: 2013

The genetic improvement of N (EUN) and P (EUP) use efficiency is a less expensive and more sustainable way to obtain satisfactory grain yields. However, the lack of knowledge about the relationship among the determinant characters of nutrient use efficiency has made the use of early and indirect selection difficult. Therefore, the objective of this study was to identify the relationship among the determinant characters of nitrogen and phosphorus use efficiency in maize. In this study, 14 lines and 39 single-cross hybrids were tested in two experiments with low and high N and P availability, in a completely randomized simple factorial design with two replications. The experiments were conducted in a shade house. Were used PVC cylindrical tubes with 4 dm3 capacity filled with two types of substrate, according to the experiment. The nutrient solutions were provided from the seventh day after transplanting, applying 250 ml tube- 1 every two days. Plants were harvested at the stage of six fully expanded leaves (V6) to evaluate the traits: shoot dry mass, specific root area, lateral and axial root length and the two components of EUN and EUP, i.e., the utilization (EUt) and uptake efficiency (EAb). According to the analyses of variance and path analysis of the collected data, EUN and EUP were not significantly influenced by the root traits. The main determinant character of EUN and EUP is shoot dry mass, regardless of the nutrient availability.

Cardoso A.D.,State University of Southwest Bahia | Alvarenga M.A.R.,Federal University of Lavras | Melo T.L.,Engenheiro Agronomo | Viana A.E.S.,State University of Southwest Bahia | Matsumoto S.N.,State University of Southwest Bahia
Revista Ciencia Agronomica | Year: 2011

With the purpose of assessing the leaf greenness of potato under application times and doses of nitrogen and potassium, this experiment was carried out in the municipality of Mucugê-BA.Three doses of N and K were used (75% of the recommended dose; the recommended dose according to soil analysis; 125% of the recommended dose). Five application times (100% upon planting; 1/3 upon planting and 2/3 upon tuberization; 50% upon planting and 50% upon tuberization; 1/3 upon planting, 1/3 upon tuberization and 1/3 25 days after tuberization; 1/4 upon planting, 1/4 upon tuberization, 1/4 25 days after tuberization and 1/4 50 days after tuberization were utilized. The experimental design was factorial (5 x 3), with plots arranged in randomized blocks with four replications. Tubercles from Ágata, Monalisa and Vivaldi cultivars, uniformly budded, were planted with spacing of 0.8 x 0.3m on a prepared soil as recommended for the culture. Was measured, throughout the cycle, the leaf greenness of potato, 30, 55 and 80 days after planting, using the indirect chlorophyll meter SPAD. The doses of N and K did not influence SPAD index, in potato cultivars over the cycle. The SPAD index can be used as a tool to indicate the most correct time for tubercule potato harvest.

Machado V.J.,Engenheira Agronoma | de Souza C.H.E.,Engenheiro Agronomo | de Andrade B.B.,Engenheiro Agronomo | Lana R.M.Q.,Engenheira Agronoma | Korndorfer G.H.,Engenheiro Agronomo
Bioscience Journal | Year: 2011

The availability of soil Phosphorus is a factor that directly interferes with its absorption by plants. This availability may be influenced by the texture, dose of phosphate fertilizer applied and the time that this nutrient is in the ground. In general, higher clay content in the soil, greater is the adsorption of P and lower is its availability, and as longer as the time P remains in the soil, lower is its availability. The experiment was conducted in the laboratory Laboratório de análises de fertilidade do solo do UNIPAM (CeFert), located on the campus of Centro Universitário de Patos Minas, in Minas Gerais. The experiment aimed to quantify the levels of available P after incubation of soils withdifferent textures. The treatments were control (no P2O5 application) and increasing doses of P2O5 (50, 100, 200 and 400 mg dm-3). Was used as the source of P2O5 monoammonium phosphate fertilizer-MAP, in soils with clay texture, medium and sandy. In the sandy soil liming was performed with commercial limestone (filler), aiming mix pH, increasing it to 6.0. After 30, 60 and 90 days of application of phosphate fertilizer were analyzed P-available by Mehlich-1. The results demonstrated that the sandy soil showed the highest P availability as a function of the applied dose and medium-textured soil showed a higher absorption and lower availability of nutrients, depending on the dose applied.

Juliatti F.C.,Federal University of Uberlandia | del Bianco Jr. R.,Engenheiro Agronomo | Martins J.A.S.,Federal University of Uberlandia
Bioscience Journal | Year: 2011

This study aimed to evaluate the incidence of fungi in cotton seed and its effect on the germination and vigour and seedling emergence under field conditions. Seeds were obtained in oil producing regions of Minas Triangle and the South of Goiás, Brazil. To compose the treatments, seeds were with their respective district producer: IAC-20-MG Centralina, IAC-20-MG Capinópolis, IAC -20 Grupiara-MG, IAC-21 Capinópolis, IAC-21-GO ofBom Jesus, IAC-22 B. Jesus, of Delta Pine Centralina, Delta Pine de Cachoeira Dourada, GO and Redemption of Capinópolis. The tests were performed in the laboratory (Health, germination and vigour) and field (emergency). From theresults, we concluded that the genotypes and sites evaluated influence the incidence of fungi in seeds; redenção cultivar had the highest incidence of Botriodiplodia theobromae; the city of Grupiara stood out for higher quality seeds produced; Botryodiplodia theobromae indirectly reduces the germination and vigor to cause the death of seeds, since the bacteria do not affect germination but affect the force represented by the emergence, while saprophytic fungi directly reduce the germination and vigor represented by the stress caused by the accelerated aging of seeds.

Agronomic performance of sorghum, millets, maize, black oats, wheat, barley, brachiaria grass, forage turnip, grain amaranth, quinoa, kenaf, sesame, sunflower, wild sunflower, pigeon pea and Crotalaria spectabilis was evaluated in sowings after summer cropping and winter, under irrigation in the Brazilian Savannah high lands. The study aimed at biomass production with impacts on soil protection and management, and source of forage, added value grains and raw material. Experiments in complete randomized blocks were conducted at three locations, with previously selected genotypes. Evaluations were based on the following parameters: plant cycle (number of days between emergence and maturity), plant height, biomass production and grain yield. Some species showed more yield stability, such as Brachiaria brizantha, sorghum, pearl millet and kenaf, and the difference for the two locations may be related to soil fertility. Plant growth and biomass production showed no effect of photoperiod, except for sesame. Grain yield indicates the potential for added value in less exploited crops for the Brazilian agriculture, such as quinoa and grain amaranth.

The objective of this study was to determine the effects of calcium on the growth of common bean plants (Phaseolus vulgaris L. cv. Talismã) in nutritive solution in the presence of aluminum. The experiment was performed in a greenhouse in the Centro de Ciências Agrárias da Universidade Federal do Espírito Santo in the municipal district of Alegre-ES. The bean plants were cultivated for 45 days in nutritive solution with increasing doses of calcium, in concentrations of 0, 25, 50, 100 and 200 mg dm-3 and a unique dose of aluminum of 15 mg dm-3. The design used was completely random, with five treatments and three repetitions. The level of 100 mg dm-3 calcium favored the development of the radicular system and the above-ground part of the bean plants, inhibiting the toxicity of the aluminum.

Schanoski R.,Engenheiro Agronomo | Righi E.Z.,Federal University of Santa Maria | Werner V.,Federal University of Santa Maria
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2011

The goal of this work was to evaluate the losses on the cutting platform, the separation and cleaning systems and total losses in mechanical harvesting of soybeans in the municipality of Maripá-PR considering the age of the combines, displacement speed and operator training. 39 machines in 25 farms were evaluated. It was observed that 79% of the machines lost more than 60 kg ha-1. The air humidity, the untrained operators and deficient maintenance and regulations were the most important factors in defining the losses. The machines with longer timer of use presented tendency of more losses in the harvest.

Rezende F.C.,Federal University of Lavras | Arantes K.R.,Engenheiro Agricola | Oliveira S.R.,Engenheiro Agronomo | de Faria M.A.,Federal University of Lavras
Coffee Science | Year: 2010

An experiment was carried out in Lavras/MG aiming to evaluate the effects of different irrigation periods on total yield, volumetric yield, and bean ripening uniformity from coffee (Coffea arabica L.) (Cv. Topazio, MG1190) that was submitted to a severe pruning 65 months after planting. The orchard was implanted in 1.8 x 0.7m spacing and was drip irrigated. A complete randomized experimental design with six treatments and four replications was implemented. Treatments corresponded to six different irrigation periods. Applied irrigation depth was equivalent to 100% of the balance including the evaporation depth from a class "A" pan and the precipitation depth measured during the time interval between two successive irrigations (ECA-P). Fertilization with nitrogen and potassium was split in 4 applications under canopy throughout the period from October to March. Data from the 2002/2003 2003/ 2004 harvest, were analyzed. Results indicated that accumulated productivity tends to be larger under the treatments receiving irrigation from April to July but retard coffee bean maturation. Irrigation increases the volumetric yield. Coffee quality (bean size and defects) from the first harvest was better than second harvest.

Garcia R.A.,Federal University of Goais | Juliatti F.C.,Federal University of Uberlandia | Barbosa K.A.G.,Federal University of Goais | Cassemiro T.A.,Engenheiro Agronomo
Bioscience Journal | Year: 2012

Considering the importance of white mold, caused by the pathogen Sclerotinia sclerotiorum, to soybeans (Glycine max) and the lack of studies about alternative control ways of plant pathogens, this study evaluated the effect of vegetable oils and extracts on the mycelial growth of S. sclerotiorum. Concentrations of 25, 50, 75 and 100 μg a.i. mL-1 of azadiractine, obtained from neem (Azadirachta indica A. Juss), were evaluated associated with the doses of 0, 1/3, 1/6, 1/8 or 1/10 of Karanja (Pongamia glabra) oil in the experiment with essential oils. Vegetable extracts of the species Schinus molle L., Ageratum conyzoides L., Ocimum gratissimum L., Artemisia absinthium L., Syzygium cumini (L.) Skeels, Ruta graveolens L., Manihot esculenta Crantz, Melia azedarach L. and Piper aduncum L. were evaluated in the concentration of 30%. Oils and vegetable extracts were incorporated, separately, into PDA culture medium and poured in 9-cm diameter petri plates, over which a PDA disk containing mycelium of the fungus was placed. The plates were incubated at 22 ± 3°C and 12 hours lighting. The evaluations consisted of daily measurements of colony diameter for two days. The greatest mycelial growth inhibition was directly proportional to the concentration increase of neem and Karanja oils. Azadiractin concentration corresponding to 100 μg a.i. mL-1 with 1/3 Karanja oil was the most effective on reducing mycelial growth, with 63% inhibition. Among the vegetable extracts, fruits of long pepper were the most promising for reducing mycelial growth, with 43% inhibition.

Garcia R.A.,Federal University of Goais | Juliatti F.C.,Federal University of Uberlandia | Cassemiro T.A.,Engenheiro Agronomo
Bioscience Journal | Year: 2012

The sclerotias are fundamental in the life cycle of Sclerotinia sclerotiorum because they are the precursor of hyphae and apotecia and, consequently, ascospores. The sclerotias production, in the laboratory, is required for studies involving this pathogen. Thus, two experiments were done, one of them was to evaluate diferents vegetables based culture media, and the another one was to evaluate the effect on cornmeal, tapioca meal and wheat meal concentrations added to common beans seeds culture medium, on the profit and the number of sclerotias production. The vegetables used in the first experiment were: carrot and sweet potato roots, leaves of cabbage, seeds of soybean, sunflower and common beans, blooms of cauliflower, fruit of tomatoes, pumpkin, snap beans and tubers potatoes, with or without the addition of cornmeal. In the second experiment evaluated the concentrations of 0, 5, 20, 35, 50, 65, 85 or 100% cornmeal, tapioca meal or wheat meal, added individually to a medium containing beans. Five mycelium disks were added to each medium in Erlenmeyer flasks after autoclaving. The flasks were incubated at 22 ± 3°C and 12 hours lighting, for 30 days (first experiment) or 45 days (second experiment). The media containing cornmeal were the most promising ones, and those containing beans seeds and sunflower seeds the ones presenting the best yield and number of sclerotias. The media containing beans, supplemented with cornmeal or ground wheat, at the concentration 20% were the best for sclerotias production.

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