Repositório RCAAP

Pesticides can be applied via aircraft, ground-sprayers or through sprinkler irrigation. However, selecting the best option is complicated by the limited number of studies comparing these techniques. Thus, we studied chlorpyrifos insecticide deposition applied via aircraft (30 l ha-1), tractor-mounted sprayer (200 l ha-1) and chemigation (70,000 l ha-1) for the control of Spodoptera frugiperda (J.E. Smith) in two corn populations (70,000 and 100,000 plants ha-1). Active ingredient residue on the leaves of the corn plants was evaluated by gas chromatography immediately after and ten days after treatment. Armyworm numbers in each plot and a control were also evaluated. Aerial and ground applications of chlorpyrifos led to greater active ingredient deposition than did chemigation. Neither plant population (70,000 and 100,000 plants ha-1) affected insecticide deposition. S. frugiperda control was similar for all three application methods. Chemigation, however, resulted in less deposition on the plants and consequently greater insecticide loss to the soil, which should be considered in assessing environmental impact.

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The present study evaluated the hypothesis that application of potassium silicate on leaf, sweet pepper plants Capsicum annuum L. (Solanaceae) is able to reduce the negative effects of water stress under greenhouse conditions. The yield (kg ha-1) and quality (leaf area index, length, diameter, shell thickness and weight of fresh fruits, dry fruits, and number of fruits / plant with and without anomalies) were quantified chili . Sweet pepper plants, hybrid Magali R cultivar, were submitted to four soil water tensions about -15, -25, -35 and -45 kPa and three levels of potassium silicate (K2SiO3) (0.0, 4, 3, 8.6 kg ha-1 of Si) via foliar application. The experimental design was randomized blocks with split plot in a 3x4 factorial design (doses of potassium silicate x soil water tension), totaling 12 treatments with four replications. The stipulated values of soil water tension were formed by sufficient levels ranging from enough water supply to the plant to water deficit, and also intermediate values. The management of irrigation was performed with the help of water retention curves for the soil and tensiometers. It was done weekly applications of potassium silicate with the help of a sprayer, a total of 21 applications. The applications of potassium silicate foliar did not increase uptake and accumulation of Si in the leaves and fruits of sweet pepper, however, there was an increased leaf area and decreased incidence of blossom end rot disease in fruit. The application of potassium silicate showed no increase in efficiency in the use of water by plant and did not interfere in the yield.

Fundação de Amparo a Pesquisa do Estado de São Paulo

Maize (Zea mays L.) cultivation has greatly evolved in several aspects in the past decades. These sets of changes, together with the need for more conclusive and available information about interactions that occur in the plant, are fundamental for the understanding of plant behavior when subjected to environmental challenges. Studies on the effects of maize defoliation, mainly during grain filling, are needed. The objective of this study was to evaluate the effects of maize defoliation on yield and on other agronomic traits. The trials were conducted in Fazenda Pombo, Uberlândia, MG, located at 860 m above sea level, in an area of grain production under no tillage. A randomized block design with 6 replications was used, as an 8 x 3 factorial, with 8 levels of defoliation and 3 hybrids. For defoliation evaluation, T1 was the control, where no leaves were removed, and T2 was the detasseled treatment. The remaining treatments consisted of leaf removal at the R2 stage (grain filling), where: T3 removal of two top leaves; T4 removal of four top leaves; T5 removal of all leaves above the main ear; T6 removal of four intermediate leaves, one above the main ear, the ear leaf and the two below it; T7 removal of all leaves below the main ear and T8 complete defoliation. The hybrids were NB 7253 (single cross HS), NB 6415 (double cross HD) and NB 7376 (triple cross HT). The traits evaluated were yield; density of ear, cob and stalk; 1,000 kernel weight; rotten grains; number of kernels per ear; number of kernels per ear row and number of ear rows; resistance to uprooting and stalk lodging resistance. It was observed that the loss of leaves in R2 stage had a negative impact on all evaluated traits, and that leaf losses greater than 40% significantly jeopardized yield and other production traits, such as number of kernels per ear, number of kernels per ear row and number of ear rows. Moreover, 1000 kernel weight, ear density and stalk and root quality, were affected regardless of defoliation intensity. The top leaves were the main responsible for grain filling. Complete defoliation considerably increased plant susceptibility to lodging and rotten grains. The removal of all leaves above the main ear was the most harmful treatment, leading to 14% yield loss.

Coffee is a perennial plant, of great importance for the national agribusiness. Currently, Brazil is the world's largest producer and the second largest consumer. The state of Minas Gerais produces almost half of the grains of the country, and the Cerrado region contributes positively to this production, according to geographic and climatic conditions favorable for this culture. However, in addition to the volume, it is important to meet the quality desired by consumers, with productivity, and competitive costs. Balancing productivity with quality requires the correct choice of the most suitable cultivar. This study compared the development of eight coffee cultivars (C. arabica) in the Cerrado region of Patrocínio, considering the variables vegetative stem diameter, plant height, crown diameter, number of flowering branches and number of nodes the primary branches. The experiment was installed in São Bernardo, farm located in Patrocínio / MG. Seedling planting was done on 10th and 11th January 2011 and data collection occurred at 6, 9 and 12 months after planting. Cultivars Acauã / FEX 1365; Red Catuaí/IAC 99 and / IAC 144, Topazio/MG 1190; Yellow Catuaí/IAC 62; Tupi/RN IAC 1669-13 (IBC-12), Mundo Novo/IAC 379 -19 and Yellow Bourbon were evaluated. The experimental design was a randomized block design (RBD), with eight treatments and four replications, with plots split in time. The plot consisted of six plants, using the four central plants for data collection. The spacing used was 3.80 m (between rows) x 0.60 m (between plants). Analysis of variance was done by the F test and when significant, averages were compared by the Scott-Knott test. The averages of evaluation times were submitted to the adjustment of the linear regression model and linear correlation coefficient were calculated between the variables. The vegetative characteristics of plant height and number of primary branches were significantly different among the cultivars. The cultivar Acauã/FEX 1365 showed lower vegetative growth in all traits. The cultivar Catuaí Vermelho/IAC 99 performed similarly to the tall cultivars. The correlation was positive and highly significant between all the characteristics. It is necessary to continue the experiment for four more harvests in order to perform the correlation between the vegetative characteristics and productivity.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Soybean [Glycine max (L.) Merrill] is considered one of the most economically important crops. In Brazil, it is grown in considerable diversity of environments. Climate changes have influenced significantly agricultural production. This study aims to evaluate adaptability and stability of soybean genotypes and to select those tolerant to excess water in the shoot in mid northern state of Mato Grosso, Brazil as well to verify check its influence on yield and physiological quality of grains. So that, the study was divided into two chapters: in the first one, the experiment was carried out in Porto Alegre do Norte MT, in a randomized block design involving 25 genotypes and four commercial cultivars evaluated in three replications. Assays were performed in harvests of 2008/2009, 2009/2010 and 2010/2011. In order to evaluate adaptability and stability, we used the following methods: Eberhart & Russell (1966), Lin & Binns modified by Carneiro (1998), centroid (ROCHA et al., 2005) and Wricke (1965). In the second chapter, the experiment was carried out in Sygenta Seeds Research Center, in the city of Lucas do Rio Verde MT in a randomized block design in three replications with 15 treatments: 10 lineages of Sygenta soybean and six control ones (Pintado, MSOY8866, FTS4188, P98Y51, TMG131 e MSOY8888). We conducted a factorial design with seven harvest times (control group: five days first crop; 10 days second crop; 15 days third crop; 20 days - fourth crop; 25 days fifth crop and 30 days sixth crop after R8), one period of rain simulation (T1 - 3h of rain simulation) and three replications. We evaluated the performance of each genotype by measuring the following characteristics: number of days to flowering (NDF); number of days to maturity (NDM), plant height (cm) on flowering (PHF), plant height (cm) on maturity (PHM), height on the first pod (FPH), total weight (TW) and weight of 100 grains (GW). We used germination test to evaluate it. The vigor, viability, damage from moisture and mechanical damages were assessed by the tetrazolium test. We used Nuclear Magnetic Resonance (NMR) method to evaluate the protein and oil content. The results of the first chapter allowed us to verify that all methodologies agreed in detaching UFU-16 as the one with most productive performance and adaptability to favorable environment, but it showed low stability. By the method of Eberhart & Russel and Lin & Binns modified by Carneiro (1998) UFU-1 and UFU-14 lineages showed high average in grain productivity, high stability and were considered as adapted to favorable environment. However, both methods Lin Binns Lin Binns modified by Carneiro (1998 and Eberhart & Russel (1966) agreed on classifying the cultivars concerning to adaptability and stability. In the second chapter, we verified superiority in BRS Pintado cultivar concerning to total grain weight and the 100 grain weight. It was considered tolerant to excess water. Lineage 2 stands out to seed quality, with higher germination and vigor.

This work aimed at investigating the influence of insecticide treatment, seed size, and storage condition in corn quality of hybrid seeds through six experiments conducted at DuPont do Brasil S. A. Pioneer Seed Division Plant, located in Itumbiara, GO. Seedling emergence field test took place in Campo Alegre Farm, in the municipality of Morrinhos, GO. The six experiments embraced all insecticide seed treatment, with two of them in cold storage at 12oC temperature and 55% humidity control; other two in storage warehouse; and two not stored at all. In both storage conditions, the experiments were different in terms of seed size, including flat seeds also known as C1 (8,92 mm width) and round seeds or R2 (8,13 mm diameter). All experiments were performed in a completely randomized design, with three replications for treatment. The treatments were also distributed in a factorial split plot 5x12, the first factor being formed by the four insecticides treatment and the no insecticide treatment; and the second factor including the 12 commercial corn hybrids. Warm germination test and cold test (vigor) were performed at a quality lab, and the percentage of emerged plants was evaluated at the field during V1 and V2 growth stages. It was concluded the following: the 15-day storage of treated seeds decreased seed germination and vigor, especially in warehouse environment; seed size affects germination and vigor of treated seeds; rounded seeds are more sensitive; corn hybrid seed treatment using carbamate active ingredients doesn t impact on germination neither on field emergence so that to impede seed commercialization; and carbofuran is the most harmful insecticide to the corn seeds, above all when seeds are not planted in the same day of the treatment.

Among the factors affecting wheat grain yield and quality, insects are notorious by the degrading effects, which can be reduced by silicon use. Despite the knowledge of silicon effects on the increase of antibiosis and non-preference of plants to apterous aphids, studies on the species Sitobion avenae (Fabricius) (Hemiptera: Aphididae) and the effect of silicon on the biology and preference for the host plant by alate aphids are scarce. This research determined the effect of silicon on the biology of alate and apterous forms of S. avenae; and the non-preference of alates for wheat plants with or without silicon fertilization. Antibiosis tests were conducted on wheat detached leaf over agar-water 1% solution in climatized chamber at 23 ºC. Non-preference tests were performed in climatized room at 23 ºC with alate aphids on vegetative and reproductive stage wheat plants. Silicon content in plants fertilized or not fertilized with silicon was analyzed. Silicon fertilization did not influence immature S. avenae mortality and development time. The greatest total fecundity was observed for apterous females on the control treatment. Silicon reduced fecundity, reproductive period and longevity of apterous females, but did not affect these biological traits of alate females. The greatest net reproductive rate (Ro) was observed for apterous on the control treatment, showing that silicon reduced fecundity of these insects. However, for alates, silicon did not affect this trait. The mean generation time (T), for both apterous and alate aphids reared on silicon treated plants, reduced. Silicon application did not affect the net rate of population increase (rm). The greatest values of the finite rate of original population increase (λ) were observed for apterous aphids, in both control and silicon fertilization. Non-preference testes of S. avenae for wheat, in vegetative and reproductive stages, showed that plants receiving silicon on its fertilization had lower number of insects than the control. Wheat plants subjected to silicon fertilization had silicon content two times greater on leaves and ears than control plants. The biology of apterous adults was negatively affected by silicon application, while the biology of alate forms was not. Silicon fertilization via soil induced resistance mechanism by non-preference on wheat plants to alate forms of S. avenae.

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Morphological markers are useful tools for identifying off-type (atypical plants) in seed production fields. However, environmental factors can cause changes in certain individuals phenotype, turning molecular markers into useful tools for verification of possible genotypic differences between these individuals and the variety studied. The aim of this study was to evaluate the efficiency of SNP markers in identifying off-type based on genotypic and phenotypic (false positive) discrimination in soybean field production. Ten lines developed by Syngenta Breeding Program located in Cascavel-PR, Uberlândia-MG and Lucas do Rio Verde-MT were used. Each line was planted in its adaptation environment in the summer season / 2009-10. Data was collected from 22 morphological features for each line. After properly describing each line, field increases of these ten lines were carried out in Planura-MG, in the winter season / 2010. In the growth stages R6 and R7 the plants phenotypically atypical for each line were collected and evaluated, to which were considered only characteristics controlled by complex genetics. The DNA of the collected plants was analyzed using SNP markers. Twenty SNP assays were used, where each marker represented one soybean chromosome in order to cover the entire genome. Among the plants considered phenotypic off-type using visual morphological traits analyses, only 27.64% were confirmed by molecular tool as genetically distinct from the standard population, with a confidence interval between 19.7% and 35.5%. The use of molecular tools is effective for the discrimination of off-type genotypic and phenotypic (false positive) process due to environmental factors, preventing the write-off of seed lots that may meet the high genetic standards.

Micronutrients are required in small amounts by plants and are essential for their development; however, micronutrient content in soil often is not sufficient to ensure high productivity, which creates the need for its application through fertilizers. This study compared availability of boron, copper, manganese and zinc to the soil, their absorption, accumulation and effect in developing maize plants, supplied from a physical mixture of NPK granules and micronutrients or from a granulated mixture NPK coated with these micronutrients. Two experiments were conducted in a greenhouse, one with Oxisol soil and AG1051corn hybrid for the first experiment and the other with an Ustox typical soil and DKB 390 VTPRO corn hybrid used in the second experiment. The formulation used was 04-30-10 (N-P2O5-K2O) with 0.1% B, 0.2% Cu, 0.2% Mn and 0.3% Zn. In both experiments, a randomized block design with four replicates were used and the formula NPK doses used were 0, 150, 300, 600, 1200 or 2400 kg ha-1. To ensure that all treatments received the same NPK amount, complementary doses of 04-30-10 without micronutrients were applied so that all treatments received the equivalent of 2400 kg ha-1 of formulated and therefore the same doses of nitrogen, phosphorus and potassium, varying only the micronutrients doses. Coating NPK granules with micronutrient was better than the physical mixture of granulated micronutrient with NPK when comparing zinc concentration in the soil; similar increments in boron contents and greater availability of copper were observed. The dry matter production of maize shoots was greatest with micronutrient coated NPK fertilizer. Also the accumulation of boron, manganese, copper and zinc in shoots of maize plants was greater when the granules of NPK fertilizer were coated.

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The place where cotton-plant is cultivated to produce seeds and its sowing time are extremely important, especially due to local climatic conditions. Based on this premise, this work aimed at verifying the influence distinct epochs of sowing in two different places had on the germination of cottonseed genotypes in the season 2007/2008. This study was carried out in two municipalities: Itumbiara, Goiás state, and Uberlândia, Minas Gerais state. Sowing of DeltaOpal, NuOpal, DP90B, DP604B, and Delta Penta genotypes seeds took place in the first half of November and in this first and second half of December. The experimental design was completely randomized in split plot with six replications. Evaluation included genotypes in the plots and sowing epochs in the subplots. After being manually harvested, cottonseeds were processed, delinted with sulfuric acid and then subjected to germination test to verify normal and abnormal (deformed, damaged and deteriorated) seedlings as well as dead seeds. Results statistical analysis allow concluding that in Itumbiara the first and second half of December are the best sowing time to produce cottonseeds from genotypes NuOpal, DP604G, and DP90B; while in Uberlândia the best sowing time were the second half of November and first half of December, no matter the genotype used.

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The use of Azospirillum genus bacteria to fix nitrogen can be useful to obtain such chemical element and, thus, reduce costs of maize cultivation. This study aimed to evaluate changes of morphological components in the production and productivity of maize as a response to application methods and concentration of Azospirillum brasilense. The experiment was carried out at Gloria experimental farm, linked to Universidade Federal de Uberlândia, state of Minas Gerais. Randomized blocks with six replications were used as experimental design. Treatments were arranged in a factorial scheme (3 X 4 + 2). The first factor consisted of two ways of spray application, one in the furrow at the base of the plant, the other at the whole plant area. The second factor consisted of different doses of inoculating (100, 200, 300 and 400 mL ha 1). Additional treatments included seed treatment by Azospirillum brasilense inoculation at 100 mL ha 1 and not inoculated seeds. The development of crop and agricultural practices relating to the management of weeds, pests and diseases were performed by the use of high technology. Evaluation focused on morphological components (plant height, green leaves, cob diameter, dry straw, length, diameter) and production components (initial and final stands, number of rows and of grains per spike, spike length and thousand grain weight and yield). It was concluded that inoculation with Azospirillum brasilense via seed treatment increases maize yield and that inoculum application via spraying and the increasing in dosage do not alter the yield of maize.

The present study evaluated the effects of genotype by environment interaction, adaptability, stability, selection of the best maize hybrids, and to stratify the most suitable environments for selection of genotypes adapted to second harvest in Central Brazil, by the methods AMMI (Additive Main Effects and Multiplicative Interaction Analysis), GGEbiplot (Genotype and Genotypes by Environment Interaction), AF (Factor Analysis) and REML/BLUP. Data from the yield evaluations from Dow AgroSciences, for 25 maize hybrids in 13 locations distributed in the States of Mato Grosso do Sul, Mato Grosso, Goiás and Distrito Federal, in two second harvests, 2011 and 2012 were evaluated .Analyses of variance were performed, followed adaptability and stability analyses. GGE biplot and AMMI analyses associated with the predicted genetic values estimated by REML/BLUP methodology allowed the indication of the best hybrids for cultivation for second harvest. The best hybrids for planting for the second harvest in Central Brazil considering the adaptability and stability were: H10, H17, H07, H05 and H09. The REML/BLUP method provides results that are interpreted directly as genotypic values and presented high coincidence with the average yield data; however, it does not identify specific interactions between genotypes x environments such as in AMMI and GGE biplot. The AMMI, GGE biplot and Factor analyses allowed stratification of environments based on altitude. The locations that have the best potential for selection of superior genotypes for second harvest were Jataí - GO, Montividiu - GO, Campo Novo do Parecis - MT and Campo Verde - MT. The GGE biplot method was superior to the models AMMI1, AMMI2 and Factors Analysis, explaining greater proportion of genotype x environment interactions and those associated with the Critical Difference Percentage (CDP) allowed the reduction of the number of environments for future trials in 23%.

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