Programa de Pós-graduação em Agronomia

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Modelagem matemática da variação espaço-temporal da temperatura média diária e do ciclo do algodoeiro herbáceo no Estado de Goiás
(Universidade Federal de Goiás, 2009-08-14) ANTONINI, Jorge Cesar dos Anjos; OLIVEIRA, Virlei Alvaro de; http://lattes.cnpq.br/0739376049142731; OLIVEIRA, Luiz Fernando Coutinho de; http://lattes.cnpq.br/5499109407814908; GRIEBELER, Nori Paulo; http://lattes.cnpq.br/2953067359172793
The regional climatic conditions in the State of Goias Brazil are favorable for herbaceous cotton (Gossypium hirsutum L. r. latifolium hutch) cultivation. However, for achieving the best productivities, it is important that both the planting date and the fruiting period be matched with the adequate soil-water availability as well as that the period from open bull to harvesting be coincident with the dry period. Thus, the knowledge of cotton cycle as function of planting location is very important for choosing the optimum planting date. In this context, the air temperature is one of the climatic variables that mostly influence the cotton growth. Nevertheless, the low density of meteorological stations with capability for measuring temperature has restricted the modeling studies for estimating cotton cycle. This work was carried out with the objective of developing and validating mathematical models to estimate average daily air temperature and based on the degreesday theory, the cycle of herbaceous cotton in the State of Goias, considering altogether its variations in space and time. Both models were based on a linear combination of elevation, latitude, longitude, and the daily time variation, represented by an incomplete Fourier series. The parameter models were adjusted to the data from 21 meteorological stations available in the State of Goiás and Federal District of Brazil, using multiple linear regressions with observations varying from eight to twenty four years. In the case of modeling degrees-day, the maximum and minimum temperature data were limited between 15°C and 40°C, which were taken as the lower and upper threshold temperatures, respectively. The air-temperature model was validated against the measured data from three meteorological stations from different elevations: high (1100 m), medium (554 m) and low (431 m). The coefficients of determination obtained from fitting the models for both daily air-temperature and daily degrees-day were 0.82 and 0.84, respectively, resulting in a medium performance for both low and high altitudes and very good for intermediate altitudes. The validation of the degrees-day model was conducted by comparing the period duration running from crop emergence to 90% open bulls observed from cotton cultivars, cropped in commercial fields. The results showed an overall performance index of 0.85, which was considered as very good. The models developed in this study adequately estimated the average daily air temperature and the cycle of herbaceous cotton cultivars in the State of Goias
Quantificação de machos e fêmeas de Heterodera glycines (Ichinohe, 1952) em cultivares de soja resistentes e suscetíveis
(Universidade Federal de Goiás, 2009-11-17) ARAÚJO, Fernando Godinho de; ROCHA, Mara Rúbia da; http://lattes.cnpq.br/4660306671671575
Soybean cyst nematode, Heterodera glycines Ichinohe, is one of the major phytopathological problems affecting the soybean, in the major producing countries of this legume. Eradication of H. glycines from contaminated areas is practically impossible. Thus, the soybean growers have to adapt control measures in order to maintain low population levels. The main control measures are crop rotation, soil management and use of resistant cultivars. With the purpose to evaluate the development of H. glycines and male/female ratio on soybean resistant and susceptible cultivars two trials were conducted during the years 2007 and 2008. Susceptible cultivars BRS Aracu, BRSGO Jatai, BRSGO Luziania, BRS Favorita RR, BRS Valiosa RR, BRS Silvania RR and resistant cultivars BRSGO Ipameri e BRSGO Chapadoes were evaluated. Soybean seedlings were transplanted to pots containing naturally infested soil with H. glycines, race 14, and, 10 days later, part of the plants remained in the pots to evaluate the females, while the other part was removed for hydroponic growth to evaluate the males. In the trial of 2008 the plants were divided in three lots, with the last one having the roots stained to count the juveniles and to evaluate survival rate. Resistant cultivars always maintained a small number of females and males, except for cultivar BRSGO Ipameri that had high countings of males. Only cultivars BRS Favorita RR and BRS Silvania RR had the expected sex ratio 1:1. All other susceptible cultivars had greater number of males than females, with ratios varying from 5:1 to 11:1. Survival rate was nil for both resistant cultivars, and varied from 6.75% to 35.00% for the susceptible cultivars. Regarding the number of cysts in 100 cc of soil the only cultivar that differed significantly from the others was the BRSGO Jatai on experiment conducted in 2007. The number of eggs per cyst varied, in both experiments, and the resistance did not influence the averages found
Eficiência agronômica de um fertilizante fonte de micronutrientes nas culturas da soja e milho
(Universidade Federal de Goiás, 2010-08-03) BARBOSA, Juliano Magalhães; FERNANDES, Eliana Paula; http://lattes.cnpq.br/7324619074753727; LEANDRO, Wilson Mozena; http://lattes.cnpq.br/9052207260053937
The present work aimed to value the agronomic efficiency of different doses of a fertilizer fount of micronutrients applied through the soil in soy culture and the residual answer in culture rotation with the corn, by the determination of chemical attributes related with the productivity. The study was performed in field s condition in a Distrofic Red Latosoil in the experimental area of the School of Agronomy and Food Engineering, in Goiânia Goiás. The experiment was performed in the harvests 2007/2008 and 2008/2009 in randomized complete blocks design with five treatments and four repetitions. Fertilizer was used as fountain of micronutrients in the form of powder containing 6,8% of manganese (Mn), 3,9% of zinc (Zn), 2,1% of iron (Fe), 1,2% of copper (Cu) and 1,1% of boron (B), in four doses and as reference the testimony: D 0 0 kg ha-1, D 0,5 33,33 kg ha-1, D 1 66,66 kg ha-1, D 2 133,32 kg ha-1 and D 1C - 66,66 kg ha-1 plus 1,4 t ha-1 of calcium oxide. The fount of micronutrient was applied only in the harvest 2007/2008 associated to the soil preparation, in the harvest of 2008/2009 there was no reapplication and the system of planting was direct, without the soil preparation. The geeting of soil and leaf were carried out in the florescence of the cultures. It can be concluded that the cultures appears to be responsive to the fertilizer by considering the productivity of both the soy and the corn and that the fertilizer doses of 128,63 kg ha-1 and 69,08 kg ha-1 showed to have the best efficiency for the productivity of the soy to the corn, respectively.
Interação entre herbicidas e cultivares de soja sobre o desenvolvimento populacional de Heterodera glycines em campo
(Universidade Federal de Goiás, 2010-11-29) BARBOSA, Kássia Aparecida Garcia; ROCHA, Mara Rúbia da; http://lattes.cnpq.br/4660306671671575
This study evaluated the effect of herbicides on the population density of H. glycines in soybean cultivars, (one resistant and three susceptible) in natural infestation conditions. Experiments were done in Campo Alegre de Goiás and Gameleira de Goiás, agricultural year 2006/07, using randomized blocks, with three repetitions. The treatments were arranged in a factorial design 4 x 4 + 1, with four cultivars (BRSGO Ipameri, BRSGO Luziânia, BRSGO Jataí BRS Silvânia RR), four forms of weed control (hand weeding, chlorimuron-ethyl + lactofen, chlorimuron-ethyl and haloxyfop-methyl), and additional treatment represented by the combination of transgenic cultivar BRS Silvânia RR and herbicide glyphosate. In agricultural year 2009/2010, another test was conducted in Gameleira de Goiás, with four repetitions, in a factorial design 2 x 4 + 2, involving two cultivars (BRSGO Chapadões and BRSGO 8360), four forms of weed control (hand weeding, lactofen, chlorimuron-ethyl; haloxifop-r), and two additional treatments represented by the combination of transgenic cultivar BRS Valiosa RR with control manual weed and chemical control via herbicide glyphosate. In the agricultural year 2006/07, in Campo Alegre de Goiás, eighty days after planting, there was less formation of viable cysts in cultivar BRS Silvânia RR associated with the application of clorimuron + lactofen, compared to manual control. In Gameleira de Goias, it was found, forty days after planting, increase in the number of viable cysts using herbicides, compared with manual control, in cultivar susceptible BRSGO Luziânia, BRSGO Ipameri, resistant to H. glycines, the number of viable cysts was lower when applied herbicides clorimuron+lactofen or haloxyfop, compared the application of clorimuron. The herbicides had no effect on the number of females in susceptible and resistant cultivars in the year 2009/10. In cultivar susceptible BRSGO 8360, the herbicide haloxifop led to a smaller number of females, in comparison with clorimuron, 45 days after sowing. The herbicide lactofen, in the cultivar BRSGO Chapadões (resistant) was associated with increase in the number of viable cysts 45 days after sowing. This herbicide affects negatively the biomass of leaves, fresh green beans and dry bean in the cultivars BRSGO Chapadões and BRSGO 8360.
Efeitos da aplicação de glifosato na química de solos alagados
(Universidade Federal de Goiás, 2010-09-10) BELTRÃO, Danielle Silva; FERNANDES, Eliana Paula; http://lattes.cnpq.br/7324619074753727; CAMPOS, Alfredo Borges de; http://lattes.cnpq.br/3249635044992714
This study aimed to evaluate the effects of the herbicide glyphosate in the chemistry of the flooded soils in two humid tropical areas included in the Brazilian savanna, observing these effects in the solid fraction and the soil solution. We used soil from an area of lowland irrigated rice cultivation and a preserved area of path, constituting, respectively, a disturbed area under agriculture and a preserved area with natural vegetation. The soils were subjected to varying periods of saturation, and applying different doses of glyphosate. The treatments were: a) Dosage: Dose 0, dose 1 (1.6 mg L-1), Dose 2 (16.0 mg L-1), Dose 3 (1600.0 mg L-1) and b) periods of saturation solutions: 1, 7, 15, 30 and 60 days. The soils were previously saturated with solutions of glyphosate prepared with distilled and deionized water, and only distilled and deionized water to dose 0, for 2 hours. After that time the volume was completed with distilled deionized and deoxygenated water. At the end of each period of saturation of soil redox potential was determined in intact experimental units, as well as the pH of the solutions after separation by centrifugation. Proceeded to freezing at - 20 ° C of the soils and soil solutions for chemical analysis and a fraction of the solutions was wrapped and refrigerated at 4 º C for later, perform the analysis of dissolved organic matter. The freezing and cooling were performed to inhibit the biological activity in the degradation of glyphosate and organic matter according to the literature. Before the analysis of the solutions we proceeded to filter membrane syringe filter to 0.45 mm in PVDF (polyvinylidene fluoride), 33 mm in diameter. Chemical analysis of soil were taken for determination of pH 0.01 M CaCl2, micronutrients (Cu, Fe, Mn and Zn), P, K, available Ca and Mg, Al, H + Al and organic matter. Chemical analysis of the solutions were limited to the determinations of Cu, Fe, Mn, Zn, K, Ca, Mg and Al and was carried out to determine the E4/E6 ratio for the humification of DOM in UV-Vis spectrometer. The different effects of glyphosate were used as the ground, showing the influence of soil characteristics and attributes in the interaction with the herbicide. The solid fraction in the analysis highlighted the effects of doses 2 and 3 in lowland soil and dose 3 in solo path. Glyphosate conferred resistance to the reduction of metals in soil and floodplain had the highest effect on the availability Eh redox sensitive elements as Fe and Mn. In the path the herbicide soil favored the reduction of metals from soil and has provided these elements. In soil solution, for the more concentrated doses, there was decreased solubilization of Fe and Mn and other elements, and affect differently the organic matter in soils, occurring in the path of higher aliphatic DOM, ie, less degradation of biological effect of dose 3. The two three doses of glyphosate and, occasionally, the first dose, influenced the chemistry of the lowland soil. The dose 3 showed more significant effects on the soil of trail. The effects of doses 1 and 2, corresponding to the doses used in the field, are highlighted as important outcomes of this study.
Volatilização de amônia e produtividade do feijoeiro irrigado adubado com diferentes fontes de nitrogênio
(Universidade Federal de Goiás, 2011-12-16) BERNARDES, Tatiely Gomes; SILVEIRA, Pedro Marques da; http://lattes.cnpq.br/4242408931816325
In the bean crop nitrogen (N) is the nutrient required in greatest quantity, being related to increases in common bean yield. As the source of this nutrient urea fertilizer is used more in the world due to its low cost per unit of N, however, its use can result in high losses due to ammonia (NH3) volatilization. This work was developed from three experiments performed in the field, conducted in the winter crop in the years 2009 and 2010, at Embrapa Arroz e Feijão, Santo Antonio de Goiás, GO, Brazil. The objective was to evaluate N by NH3volatilization loss, using different sources of nitrogen fertilizer applied to irrigated common beans. The first experiment was a randomized block, with four replications, in a factorial 3 x 4, consisted of three sources of nitrogen fertilizer, urea, urea + NBPT and gradual release N fertilizer, and four rates of N, 0; 50; 100 and 150 kg ha-1, on side-dressing fertilization. In the second experiment, the design was a randomized block, with four replications. The treatments consisted of four different amounts of straw tifton (Cynodon spp. Cv. Tifton 85) on the soil surface, 0; 5; 10 and 20 Mg ha-1, and side-dressing fertilizer nitrogen with two sources, urea and gradual release N fertilizer. The third experiment was in randomized block design, with five repetitions. The treatments consisted of the application of five sources of nitrogen fertilizer, urea, urea + NBPT, urea + polymer, ammonium sulphate and ammonium nitrate at sowing and in coverage, more control (without N). The N rates had a positive influence on grain yield of common bean. Urea caused higher NH3 volatilization, however, the conditions of the present study these losses were relatively low. Less accumulated volatilization occurred in soil with 20 Mg ha-1 straw tifton soil surface, due to higher soil water storage. The urease activity in soil was not influenced by the sources and rates of N. The common bean grain yield was not influenced by sources of nitrogen fertilizer.
Aplicabilidade do sistema de avaliação da aptidão agrícola das terras frente à realidade do processo produtivo agropecuário goiano
(Universidade Federal de Goiás, 2008-02-27) BORGES, Lino Carlos; OLIVEIRA, Luiz Fernando Coutinho de; http://lattes.cnpq.br/5499109407814908
There are several works which aim to equate the agricultural production in function of the best use of natural resources as soil and water, in the attempt of obtaining the maximum of effectiveness in the productive system, and upon this context the evaluation of the potential of using the lands has major importance for a correct planning of agricultural activities. The elaboration of maps of agricultural aptitude is of extreme importance for the sustainable use of soil and water, it should be the first and more important instrument of agricultural planning. Because of this, the elaboration of those maps should be accompanied of a discerning methodological process, focused mainly in the socioeconomic aspects aiming to adequate it to the various levels of soil handling present nowadays. This work has as objectives: 1) Research the applicability of the evaluation system of the lands agricultural aptitude regarding the actual conditions of the agricultural productive process for two areas of the State of Goiás, basin of drainage of Córrego das Pedras and of Ribeirão Jurubatuba (nascent of Ribeirão João Leite) and of the immediate surrounding of the National Park of Emas; 2) Look for latent factors responsible for the large variability of the lands aptitude in the studied areas, and detect the similar samples considering this clustering, using for this multivariate techniques of factor analysis of principal components and discriminative. The work considers quantifying and comparing the elements of production among the various classes of agricultural aptitude, establishing qualitative differences among those aptitude classes and the handling levels, comparing the theoretical model proposed in the studies against the several realities of the researched areas. The data related to the soil types, agricultural aptitude and handling levels recommended were gathered from maps elaborated for the two areas being studied. Data regarding productivity, production costs, land value, gross revenue and local adopted technology were obtained from personal visits and direct interviews with a sample of 52 farm properties for the agricultural year of 2006/2007. Based on the information found in the 52 analyzed samples, the use of factor analysis was shown to be promising, for this study area, being an innovative aspect in the interpretation of data related to the agricultural aptitude. Two techniques of statistical multivariate analysis were used: factor analysis aiming to reduce the columns of the original matrix (variables in study) through the identification of latent factors, synthesizing the common information over all variables; and the discriminant analysis with the objective of classifying the observations, with known data. These analyses indicated that productivity and production cost are related and that a possible explanation for it may be due to the levels of handling and technology, as with the gross income it may be explained by other elements as the business opportunity, market value for the products, and not necessarily with the level of technology. It was verified also a need for establishing greater and more meaningful details regarding the handling levels for the cases of pasture and forestry. Because of the peculiarities and diversity of production systems found in the basin of Ribeirão João Leite, the system of agricultural aptitude of the lands proposed by Ramalho Filho & Beek (1995) was considered insufficient, for suggesting only three handling levels, while the dispersion of the data regarding production, productivity, production cost and gross revenue, demonstrates the need of better discrimination or hierarchization of the handling levels. For the area of the immediate surrounding of the National Park of Emas the system of agricultural aptitude was shown to be more appropriate on the handling levels recommended. The system proposed by Ramalho Filho & Beek (1995), in a certain way, plasters or limits the expectations one could have relative to the potential of certain cultures, soils and used labor force, regarding the productivity and profitability of some agricultural and forestry activities. It was verified also that the handling levels are extremely important, and they should be in greater number and more detailed than the existing 3 handling levels (A,B and C) proposed by Ramalho Filho & Beek (1995).
Correção do solo e sistemas de rotação de culturas sobre a absorção de nutrientes e produção de soja
(Universidade Federal de Goiás, 2011-02-25) CAETANO, Jeander Oliveira; CARNEIRO, Marco Aurélio Carbone; http://lattes.cnpq.br/4868736525994145; PEREIRA, Hamilton Seron; http://lattes.cnpq.br/4532276726985491
Crop rotation and the increase in straw on the soil are among the main requirements for the implementation and maintenance of no-tillage in the Cerrado. The use of integrated crop and livestock production, coupled with the introduction of Brachiaria in agricultural areas has helped to maintain this coverage and increased amounts of plant species as alternatives to rotation. Thus, there is a need to evaluate these cover crops and forms of fertility management which are widely used by farmers in Brazil. The aim was to evaluate the effect of two forms of soil correction, four types of soil cover and four levels of KCl on production and nutrient content of aerial part dry biomass of soil cover types, the yield and content soybean leaf nutrient and chemical attributes of an Oxisol. The experimental was arranged in a randomized block design, with four replications, the field was laid out in 2x4x4 and arranged in strip-split plot design. Was evaluated the forms of soil correction initial total and annual installment (main plot), the types of soil cover Brachiaria brizantha, B. ruziziensis, sorghum crop residues and spontaneous vegetation (subplots) and the levels of KCl correspondents to 0 kg ha-1, 20 kg ha-1, 40 kg ha-1 e 60 kg ha-1 of K2O (subsubplots). On the soil, for the depths 0-20 cm and 20-40 cm analyzed the pH CaCl2, organic matter, exchangeable Ca, Mg, K and Al, H+Al and the contents of available P, Fe, Mn, Cu and Zn. In the leaves were determined N, P, K, Ca, Mg, Fe, Mn, Cu and Zn. Was collected dry biomass of soil cover and estimated soybean yield. The forms of soil correction initial total and annual installment not influence soybean yield. B. brizantha produces highest biomass, which occurs in the highest soybean yield. Potassium is the nutrient of greatest accumulation in leaf of B. brizantha and B. ruziziensis. The increasing levels of KCl do not affect the soybean yield. The soybean yield is more affected by the kind of cover crops than by the form of correction and levels of potassium.
Uso de nitrogênio no cultivo de arroz irrigado e seus efeitos no solo, na planta e na emissão de óxido nitroso
(Universidade Federal de Goiás, 2011-02-15) CARVALHO, Glaucilene Duarte; FAGERIA, Nand Kumar; http://lattes.cnpq.br/1794909905335127; CAMPOS, Alfredo Borges de; http://lattes.cnpq.br/3249635044992714
In wetland soils are countless electrochemical changes, among the most influenced by anaerobic conditions is nitrogen. The rice crop also determine changes in the process, either by the nutrient uptake or by changes in the rhizosphere. The nitrogen can guarantee high yields of rice, however, due to the inadequate use of nitrogen can have nitrous oxide, which is a greenhouse gas. In this context, the research aimed to determine the effects of nitrogen fertilizer in flooded lowland soils in soil chemistry and soil solution on the plants and the emission of nitrous oxide. The experiment was conducted in pots at Embrapa Rice and Beans. The treatments consisted of two rice genotypes (BRS Tropical and BRA 051130) and three nitrogen (0, 150 and 300 mg N kg-1 soil). The experimental design was randomized blocks with split plots. The flooding of the vessels took place on the fifteenth day after planting. The collection solution was given 1, 3, 7, 14, 28, 39, 59, 67, 102 days after flooding. The collection system consisted of a perforated plastic pipe and secured in the vessel walls, being closed at the ends. The solution was suctioned through a syringe and then analyzed on Ca, Mg, K, P, Fe, Mn, NO3 -, NH4 +, pH and Eh (directly to the pots). After the experiment was made at the soil sampling vessel, comprising all the other treatments being performed analysis of Ca, Mg, K, P and soil pH. The yield components studied were: plant height, tiller number, panicle number per plant, panicle length, spikelet sterility, dry weight of 1000 grains, shoot dry weight, root dry mass, grain yield, root length, grain harvest index, the contribution of the shoot dry weight total contribution of root dry weight total. The method of collection of nitrous oxide was a closed chamber in PVC material. Collections were undertaken throughout the rice cycle and N2O concentration was measured by reading in a gas chromatograph. The results were subjected to analysis of variance, treatment means compared by Tukey test. The pH, exchangeable Ca, Mg, K and P in soil increased after the implementation of the experiment. The values of Eh in soil solution decreased with time of flooding and consequently the pH increased. The concentration of Ca and Mg in soil solution increased with time of flooding and the K, Mn, NO3 -, NH4 + declined over the period. The rice genotypes showed differences in dry weight of 1000 grains. The dry weight of shoots showed responses to nitrogen fertilization, since the height of the trees showed responses to genotypes and N levels The total emission of N2O showed differences in nitrogen use and for the rice genotypes. We observed that the genotype BRA 051130 showed significantly higher total emission in relation to the treatment without plants.
Produção de óxido nitroso de solo cultivado com feijoeiro comum irrigado em sistema plantio direto no cerrado
(Universidade Federal de Goiás, 2011-02-24) COSTA, Adriana Rodolfo da; MADARI, Beata Emoke; http://lattes.cnpq.br/0302689027695014
The loss of nitrogen from the soil-plant system has economic and environmental repercussions, especially when nitrous oxide is emitted to the atmosphere. The aim of this study was to evaluate the emission of nitrous oxide (N2O) in the production system of irrigated commom beans under no-tillage, with brachiaria grass as cover plant (green manure), as affected by the application of different N sources. The experiment was conducted at Embrapa Rice and Beans, in a clayey Haplic Ferralsol. Six areas planted with common beans in no-till system, with sprinkler irrigation, center pivot, were evaluated in the fall/winter period of 2009. In each area (150 m2) a different source on N (treatments) was applied. The total area of the study was 1000 m2. The treatments were: no N (control), urea, ammonium sulfate (A.S.), urea + urease inhibitor (Ur.+Inhi.), urea combined with charcoal (Ur.+Car.), biological fixation nitrogen (B.F.N.), Cerrado (Cer). One hundred kg of N ha-1 was applied in all areas: 20% at sowing together with the seed at the same depth and 80% as top dressing, 25 days after planting. Periods, whose N2O fluxes were more important, were selected for more detailed study, including soil biological variables. The N2O concentration was determined by gas chromatography. Concurrently, soil moisture, temperature, water filled pore space (WFPS), pH and parameters related to the microbial biomass were also measured. The variables that influence soil N2O fluxes during the growing cycle of the bean are: the levels of nitrate in the soil, pH, moisture and WFPS, indicating conditions that favor the denitrification process. The highest emissions of N2O, occur in the following treatments: urea with urease inhibitor, biological nitrogen fixation and urea associated with charcoal, 70%, 36% and 32% higher then that observed in the control, respectively. The emission factors observed in this study are below the lowest levels suggested by IPCC (Intergovernmental Panel on Climate Change). After fertilization at sowing, the variables that control the emission of N2O are basal respiration, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), total organic carbon (TOC), soil moisture and WFPS. The charcoal combined with urea provides better conditions for microorganisms, increasing MBC and microbial quocient. After topdressing N2O fluxes are lower than at sowing, possibly due to higher N losses through volatilization or increased demand for N by the plant and consequent higher N uptake by plants. The ammonium sulfate source shows the highest N2O fluxes in this period. The variables that control N2O emission in this period are: MBN, pH, moisture and WFPS. During the senescence of the bean plants urea combined with urease inhibitor and biological fixation nitrogen are the treatments that most emitt N2O. The variables that controll the fluxes are soil temperature and TOC.
Epidemiologia da ferrugem asiática da soja em ambientes do Estado de Goiás: efeito de fungicida e época de semeadura
(Universidade Federal de Goiás, 2005-02-28) CRUVINEL, Adriane Reis; OTTONI, Giselle; http://lattes.cnpq.br/4584420838543565
During the last crops, the soybean rust has been appeared as one of the most important problems in the national agriculture. The direct loses on the production and in the costs with fungicides have been increased the damages on this crop. Aiming to understand better the disease epidemiology, this work searched for answers by epidemic progress in two locations, the time of planting effect, the cycle of planting, the use of fungicide, and by different cultivars. The experiments were assembled in Experimental Stations from Agência Rural in Senador Canedo and in Anápolis. For each place were used three times of planting, six cultivars on the three crop cycles (Monsoy 6101 and BRSNina premature cycle; Emgopa 315 and BRSGO Santa Cruz middle cycle; Emgopa 313 and BRSGO Paraíso late cycle), with and without fungicide action, have been evaluated on the three parts of the plant (lower, middle and upper). Each time, to each one of the places, have been considered as an experiment with spli-split-plot. After the disease symptom observations, the split under chemical control were freaked each 21 days using pyraclostrobin+epoxiconazole on 66,5 g + 25 g a.i. ha-1. The evaluations, after the first symptom observation, have been done weekly up to the complete leaves took away. With the periodic severity data the Area Under Progress Disease Curve (AUPDC) and Relative Area Under Progress Disease Curve (RAUPDC), that is the area divided by the epidemic time duration, were calculated. The parameters were productivity, thousand-grains weight (TGW) and small grains percent (%SG). The delay on the start of the disease on Anápolis, comparing with Senador Canedo, increases the discussion on the results. The previous disease occurrence in Senador Canedo and the high level inoculate presented can be associated to the fact of experimental site in Senador Canedo has soybean cultivate all over the year. The delay on the start of the disease on Anápolis, compared to Senador Canedo has been resulted on productivity increase and fungicide effect decrease. Comparing the time of planting in both planting places, the second one presented the highest level of severity, but the highest level of productivity even. The use of fungicide decrease significantly the AUPDC, increase the productivity, the TGW and decrease the %SG. The premature cycle cultivars presented lowest disease severity. The cultivar Emgopa 315 although be a medium cycle presented results equals premature cycles cultivars. On each site the time of planting were differentiated. On high pressure inoculate condition the difference between evaluated factors was lower. On lower inoculate pressure the evaluated factors expressed better the changes. As conclusion we have: a) how early the disease appears higher is your effect on productivity; b) using premature cultivars the escape effect decrease the disease damages when compared to medium and late cycle; c) the disease decrease the soybean cycle by the defoliation; d) although all the cultivars presented susceptibility to rust, related to lower severity on partial resistance; e) the fungicide utilization pyraclostrobin+epoxiconazole on de 66,5 g + 25 g a.i. ha-1, used on first symptom and in 21 on 21 days decrease the disease progress and the effects on productivity; f) the disease progress decrease by fungicide utilization is better in late planting; g) under the fungicide effect pyraclostrobin+epoxiconazole with 66,5 g + 25 g a.i. ha-1 there s no variation time planting and site; h) under high inoculate pressure the variation between time planting on disease progress and productivity is lower; i) the time of planting must be considered but not lonely, always in association with others factors of fungus action; j) the use of RAUPDC is necessarily when there is variation the time of soybean cycle, affecting the rust epidemic duration; l) the highest disease level occurs on the part of the plant near the soil and the defoliation difficult the disease evaluation on this part of the plant; m) the most effective disease occurs on the highest parts of the plant.
Manejo da irrigação do feijoeiro cultivado em plantio direto no sistema integração lavoura-pecuária
(Universidade Federal de Goiás, 2009-02-26) CUNHA, Paulo César Ribeiro da; NASCIMENTO, Jorge Luiz do; http://lattes.cnpq.br/1613681986702987
The water is becoming a resource more and more scarce, with growing strategic importance in the sections environmental, economical, social and political. The irrigated agriculture is responsible for considerable portion of the agricultural production, however, it is the activity that more it demands water. In the irrigated areas, one of the most important factors is the determination of the water levels for replacement of the losses happened in function of the evapotranspiration, with consequent it gets better of the productive efficiency. Inside of this context he becomes evident the need of administration of the applied water for the irrigation. The objective of this work was to evaluate the acting of three irrigation management methods in beans crop cultivated in direct planting in the system integration farming-cattle; the methods were appraised as for the estimate of the evapotranspiration, levels and irrigation frequency, productivity of grains and their components. It was also evaluated in the periods annual, dry and rainy season, the acting of methods of determination of the coefficient of the class A pan (Kp), and still, the possibility of adoption of a fixed value for such variable. The evaluation was made within the dear evapotranspiração with class A pan using the appraised coefficients and the dear for the standard method Penman-Monteith (FAO 56). The work was driven in the experimental area of Capivara farm, Rice and Beans Research Center in Santo Antônio de Goiás, Goiás State, Brazil. In the evaluation of the irrigation management methods the common bean crop was used (Phaseolus vulgaris L.) cv. BRS Supremo; the appraised methods were tensiometry, class A pan and Penman-Monteith. There were significant differences as for the productivity, number of grains for plant and height of plants in relation to the irrigation management methods, tends the class A pan propitiated the obtaining of larger yield, due to the largest total water, and of the largest irrigation frequencies, the management for tensiometry caused reduction of 40% in the total demand of water of the beans crop, however, with significant reductions in the productivity, tends the class A pan overestimated and of the underestimated tensiometry the total water esteemed by the standard method FAO 56 Penman-Monteith. Independent of Kp, the method of the class A pan overestimated the evapotranspiration obtained with Penman-Monteith. For the climatic conditions in which he took place the work, the best method of determination of Kp, for the estimate of ET0 in the annual period was it of Pereira et al. (1995). For the dry season it was it proposed by Cuenca (1989). In the rainy season all of the methods presented low actings, however, Pereira et al. (1995) method it was shown more efficient. It was observed that the method of the class A pan is not efficient to esteem ET0 in the rainy season. The analyses showed that the adoption of a fixed and constant Kp in 0,70 showed in high acting, mainly in the annual and dry seasons.
Otimização da detecção de raquitismo da soqueira e escaldadura das folhas em cana-de-açúcar utilizando PCR
(Universidade Federal de Goiás, 2012-03-02) DIAS, Vanessa Duarte; DIANESE, Erico de Campos; http://lattes.cnpq.br/2503998782869167; CUNHA, Marcos Gomes da; http://lattes.cnpq.br/2006008625763742
The sugarcane production areas are increasing in Brazil due to increased ethanol consumption by flex fuel cars. The planted area is growing, but productivity has been declining in recent years, and factors such as incidence of diseases in the crop may be contributing to this situation. Among the diseases, bacteria such as scald of the leaves and ratoon stunting disease, are of great importance to the crop because they can reduce productivity by up to 30% and the symptoms are not always displayed in the field, thus requiring advanced techniques to detect such bacterial diseases. Among the most used techniques for diagnosis serological tests are quite common, which has as main advantage the capacity of quantitative detection of the presence of bacteria in the culms. However, this detection is only possible if the bacterial title is relatively high. The PCR technique method is more sensitive for detecting low levels of bacteria in stems, but the DNA extractions should be performed in order to purify the DNA to reduce the presence of inhibitory substances in the extract. Thus in this study five different methods of DNA extraction of Xanthomonas albilineans and Leifsonia xyli subsp. xyli were tested and performed in three steps: pure bacteria, bacteria inoculated directly in the extract from five different varieties of sugarcane, and extract from a stem knowingly infected with these bacteria. The results indicate that the amplifications occur more frequently when the products and repeatability of the extractions are diluted by 10-4 in the Leaf Scald. Without this diluition steps, the amplification does not occur, even with the method of DNA extraction considered as a standard. Thus, it is concluded that the detection does not happen if the DNA extraction product is not diluted at least 1000 times, which should prevent the action of inhibitory factors that can hinder the PCR reactions. As for the ratoon stunting disease additional studies are needed to enable its detection by PCR.
MÉTODOS DE PREDIÇÃO E ESTIMAÇÃO DE VALOR GENOTÍPICO E ESTRATIFICAÇÃO AMBIENTAL PARA AVALIAÇÃO E RECOMENDAÇÃO DE CULTIVARES
(Universidade Federal de Goiás, 2008-06-13) FELIPE, Cristiane Rachel de Paiva; DUARTE, João Batista; http://lattes.cnpq.br/4117228759548186
This research had the objective of evaluating the effects of different statistical approaches for the selection and ranking of genotypes, in the context of maize varieties trials. For that, data from real trials designed in lattice were used, in the Goiás State, Brazil, in the growing seasons of 2002/2003, 2003/2004, 2004/2005 and 2005/2006, as well as data from simulated experiments, aiming to cover situations related to that reality. The study also intended to quantify the effects of the genotype by environment interactions (GxE) from the real trials, aiming for the environmental stratification for the maize cultivation in the State, pointing out the cultivar evaluation and recommendation. Considering those objectives, the study is divided in three scientific articles. In the first one (Chapter 3), the effects of approaches of fixed model (FF), mixed model with random effect of blocks (AF), mixed model with random effect of treatments (FA), random model (AA), and James-Stein s estimator (JS) were evaluated on the selection and ranking of genotypes tested on the maize varieties trials, coordinated by the Agência Goiana de Desenvolvimento Rural e Fundiário (AgenciaRural Goiás). The experiments, in number of 47, were installed in lattice design, with three replications, during the four cited harvest years. In the second article (Chapter 4), the same approaches were evaluated, in terms of accuracy, mean predictive deviation and precision of their estimates/predictions, considering the simulated trials, also in lattice. Forty-eight cases were considered, corresponding to the combinations of different experimental sizes (15, 54, 105, and 450 treatments), genotypic determination coefficients h2' (6%, 15%, 25%, 48%, 63% and 82%), and two probability distributions for the generation of genotypic effects (normal and uniform). One thousand trials were simulated for each case, reaching the total of 48,000 experiments. The third and last article (Chapter 5) refers to the study of the GxE interaction, emphasizing the already mentioned environmental stratification, where the winner genotypes approach in association with the AMMI analysis (additive main effects and multiplicative interaction model) was adopted. Among the results and conclusions achieved through this study, it is possible to point out: i) the adoption of statistical approaches with shrinkage effect on the genotypic means results in the selection of a lower number of genotypes, especially in those trials whose mean of the check cultivars (baseline to the genotypic selection) is higher than the experimental grand mean; this fact reduces the number of genotypes with low yield potential in the next cycles of the selection program; ii) the use of models with fixed effects of treatments leads to a higher percentage of selected genotypes, mainly in the experiments whose check varieties mean overcomes the experimental grand mean; iii) among the shrinkage statistic approaches evaluated, the AA model must be preferred for the selection of genotypes, due to its capacity for better predicting the parametric genotypic effects (higher accuracy and lower mean predictive deviation), no matter if these effects are normally or uniformly distributed; iv) on the other hand, the FF model shows the worst relative performance, except for the situations where the variability among the genetic treatments is high (h2 ®1,0); v) considering low values for h2 (6%), the FA model shows efficiency similar to the AA model; vi) two established environmental strata showed to be consistent throughout the years, even when the tested genotypes were altered from one harvest season to the other: Ipameri, Inhumas and Senador Canêdo (stable to four years), and Porangatu and Orizona (stable along three years); vii) considering the obtained clustering, it is possible to reduce, at least 16%, the number of test locations currently used, and/or substitute the redundant locations by test places which better represent the recommended target region, aiming to increase the evaluation efficiency of the GxE interaction, in the scope of the genetic plant breeding program; viii) the ALBandeirante variety presents high yield potential and adaptability to the maize cultivation conditions in the Goiás State.
Reação de genótipos de soja e milho ao nematóide das lesões radiculares Pratylenchus brachyurus
(Universidade Federal de Goiás, 2010-03-01) FERREIRA, Anderli Divina; ROCHA, Mara Rúbia da; http://lattes.cnpq.br/4660306671671575
The soybean crop (Glycine max L. Merr.) is present in practically every Brazilian state occupying an area of 23 million ha. The Central West Region is considered the greatest grain producer. The annual losses due to diseases are estimated around 15% and 20%. Among the main crop diseases in the Cerrados region, the ones caused by nematodes, especially H. glycines and P. brachyurus, are very important. Occurrence of P. brachyurus has been increasing, especially in areas of no till and pastures. The corn crop usually planted in crop rotation with soybean is also susceptible to P. brachyurus, which makes more difficult the nematode management. The use of genetics resistance is one of the most important control strategies due to its compatibility with other practices and for not being environmentally harmful. The purpose of this study was to evaluate the soybean and corn genotypes reaction to the nematode P. brachyurus, aiming the identification of resistance that could be of immediate use for growers in crop rotation system or to identify sources of resistance that could be used in plant breeding programs. The reaction of 50 soybean genotypes and 38 corn genotypes to P. brachyurus was studied under naturally infested field conditions. The experiments were conducted in 2008/09 in a randomized block design with split plot scheme, with evaluations at 30 and 60 days after emergence (DAE). Soybean experiment had eight replications and corn experiment, ten replications. The root samples were collected and taken to the laboratory for nematode extraction. The results were expressed as number of nematodes/ 10 g of roots. The reproduction factor (RF) was calculated considering the evaluation at 30 DAE as the initial population and the evaluation at 60 DAE as the final population. The soybean cultivars were separated into two groups with high and low susceptibility to P. brachyurus. Twelve genotypes presented interaction with the evaluation timing. Ten out of these twelve genotypes had the P. brachyurus population reduced from 45% to 70% at 60 DAE. The cultivars BRSGO Luziania RR, BRS Juliana, M-Soy 7211 RR, M-Soy 8411, TMG 103 RR and Emgopa 316 had 70%, 62%, 61%, 58%, 58% and 57% reduction in the population densities at 60 DAE. The cultivars were also separated into to groups according to the RF. The corn genotypes were separated into three groups. Seventeen corn genotypes had significant interaction with the evaluation timing and only the genotype Agromen 30A06 had the population density reduced (57%) at 60 DAE. All the other 16 genotypes had the nematode population increased between 30 and 60 DAE with increasing variation from 42% to 85%. The genotypes with lowest population density at the final evaluation (60 DAE) were: P 30F80, P30S31, Agromem 30A06, AS1575, DKB 499, GNZ 2500, DKB 350, DG 501 e NK Impacto. The soybean and corn genotypes that presented lower population density and RF along the evaluation period must be preferred for planting in infested areas and can be considered for future investigation for genetic resistance.
Produção de frutos e entomofauna associada ao pequizeiro (Caryocar brasiliense CAMB.) no cerrado do estado de Goiás
(Universidade Federal de Goiás, 2007-09-21) FERREIRA, Gislene Auxiliadora; NAVES, Ronaldo Veloso; http://lattes.cnpq.br/2740049203016314; CHAVES, Lázaro José; http://lattes.cnpq.br/9990967290797379; VELOSO, Valquíria da Rocha Santos; http://lattes.cnpq.br/7952914949535819
The Brazilian Savannah is rich in biodiversity and possess high number of fruitful species with potential of use for human consumption. The pequizeiro is a native species of the Savannah with economic and cultural importance for Midle-Western Brazil, needing, however, techniques that make possible the implantation of orchards, its conduction and the harvest of fruits, aiming at to reduce the pressure on the natural environment, as well as the maintenance of the regional culture. The present work considers to characterize the production of pequizeiros of natural occurrence in fifteen dispersed populations in five regions of the State of Goiás; to study the occurrence, behavior and bioecology of entomofauna present in the plants of the pequizeiro in sixteen populations of pequizeiro of the State of Goiás; e to evaluate the occurrence of Eunica bechina in fourteen locations of this State with raised natural occurrence of pequizeiros and its potential of plague. The criterion of election of the populations considered the biggest space dispersion of these, the bigger production of fruits, and the relative nucleation of the trees of pequizeiro in each population. The studied pequizeiros had presented averages: production (132,28 fruits/plant), diameter in the base (0,40 m), diameter in the height of the chest (0,35 m), total height (7,64 m), height of the pantry to the ground (2,97 m), projection of the area of the pantry (83,34 m2), with 1,58 average frutos.m-2 of projection of the area of the pantry in the ground. Promising plants for future programs of improvement of the pequizeiro exist. The production of the pequizeiro is irregular in the State of Goiás between harvests, plants and population, being considered on average low. There is one raised group of organisms interacting with the pequizeiro , being distinguished the insects that can contributed for the production. The species gotten with the percentages of occurrence in the different populations belonged to the orders, respectively: Hemiptera (25.64%), Coleoptera (17.95%), Lepidoptera (16.67%), Hymenoptera (15.39%), Díptera (11.54%), Orthoptera (6.41%), Neuroptera (2.56%), Isoptera (1.28%), Thysanoptera (1.28%), Psicoptera (1.28%). The joined species in the sixteen pequizeiro populations had more frequently been: Eulechriops sp. (100%), Atta laevigatta (93.75%), Eunica bechina (93.75%), Lyriomisia sp. (93.75%), Edessa rufomarginata (100%) and Rhodoneura intermedia (100%), Phydotricha erigens (81.75%). The species T. tibiali, A laevigatta, R. intermedia, Carmenta sp., E. rufomarginata and E. bechina can be considered potential plagues of the pequizeiro in the Savannah of the State of Goiás. It is needed more studies on the contribution of the fauna, illnesses, the one grass-of-bird and of the insolation in the production of the pequizeiro . It is necessary the establishment of sustainable measures of handling for the extractive and the plantation, conduction and production of fruits of the pequizeiro .
Eficiência do inseticida thiamethoxam aplicado no momento da colheita da cana-de-açúcar para controle de Mahanarva fimbriolata (Stål.,1854) (Hemiptera: Cercopidae) e seus efeitos na produtividade
(Universidade Federal de Goiás, 2009-06-29) FERREIRA, Henrique de Jesus; FERNANDES, Paulo Marçal; http://lattes.cnpq.br/9497281141847296
The objective of this study was to evaluate the efficacy of the insecticide thiamethoxam in simultaneous application with sugarcane harvest, under mulch, using a mounted sprayer system in the harvester machine and manual application method to control of Mahanarva fimbriolata. The experiments were carried out in the municipal district of Goianésia, Goiás State, in the period from October 2007 to September 2008. Two experiments were carried out set up side by side, in the same area. One experiment was applied using the sugarcane harvester, with a mounted sprayer system set up behind of the harvester, spraying the insecticide over the crop line and covering with mulch right after. The second experiment was applied in the manual method using a backpack sprayer pumped by CO2. The trials were set up in randomized blocks with six replicates. It was tested four rates of thiamethoxam, commercial brand named Actara 250 WG®. The tested rates were: 0 (untreated check), 100, 150 e 200 grams of active ingredient per hectare. The root froghopper infestation in the experiments was evaluated at 35, 75, 127 e 191 days after application. The parameters evaluated at the harvest timing were stalks diameter and yield increase. It was adopted the biometry method to estimate the yield. The M. fimbriolata infestation fluctuated during the evaluated period and the higher infestation level occurred in December and April. It was observed a negative significant correlation between the rates of thiamethoxam and the infestation level of M. fimbriolata to the two application modality. Thiamethoxam provided significative reduction of M. fimbriolata until 191 DAA for all rates, compared to untreated check (dose 0). Regarding the influence of the insecticide in stalks diameter it was observed a significant increment of 10,46% at rate of 100 g of active ingredient per ha when applied in the harvester machine. The treatments did not affect the yield (t ha-1). The application modality of insecticide under mulch, at harvest timing, using a mounted sprayer in the harvester machine showed to be a viable option in the sugarcane crop.
Características fitotécnicas e acúmulo de nutrientes em cultivares de crisântemo para vaso, em Goianira - GO
(Universidade Federal de Goiás, 2009-03-19) FERREIRA, Luciana Domingues Bittencourt; NASCIMENTO, Jorge Luiz do; http://lattes.cnpq.br/1613681986702987
The market of chrysanthemum has grown in recent years, mainly due to its versatility as a product, which gives color and shape varied, and affordable to many consumption patterns. But there is a need for adequacy of technical and scientific information on culture, especially depending on the opening of new producing areas in Brazil and the introduction on the market of new cultivars. The objective was evaluate the performance of three cultivars of chrysanthemum in pot grown in the Goianira - GO between the months of August and October 2007. Plant characteristics were evaluated, quality, and determined to the nutrient uptake rate of the cultivars. Worked with the cultivars White Diamond, Eugene Yellow and Durban in five phenological stages, 20, 34, 48, 62 and 76 days after the planting - DAP. Treatments were arranged in a 3x5 factorial in completely randomized design with five replications. The results found that the cultivar White Diamond presented the lowest dry matter accumulation in all plant organs analyzed. Eugene Yellow showed the highest dry matter accumulation of leaves and stems, and accumulated more in Durban and plant flowers. With respect to phenological stages, the dry matter accumulation in different organs has been growing throughout the production cycle, reaching accumulations of 6.02, 8.75 and 9.55 for g.plant-1 White Diamond, Eugene Yellow and Durban, respectively. The scale of marks for the classification standard of quality, the cultivars had values within the limits pre-established by standards. The accumulation of nutrients in various organs of the plants differed between cultivars. In cultivar White Diamond, the N, K and S are accumulated in larger quantities by inflorescences, P, Ca, Mg and Mn in leaves and Cu and Zn in the stems. The highest accumulation of nutrients in Eugene Yellow were N, K, Mg, Mn and Zn in leaves, P, Ca and Cu in stems and flowers in S. Cultivar in Durban, the largest accumulation of N, P, K, Mg and S were observed in the inflorescences, and Ca in the leaves. Demand for nutrients has been increasing throughout the production cycle with the maximum observed 76 DAP. The total accumulation of macronutrients for the cultivars showed the following order: K> N> Ca> P> Mg> S. And to cultivate White Diamond and Eugene Yellow was the sequence of micronutrientes Mn> Zn> Cu.
Adubação potássica via solo e foliar na produção e qualidade da fibra do algodoeiro
(Universidade Federal de Goiás, 2006-08-15) FREITAS, Roberto José de; LEANDRO, Wilson Mozena; http://lattes.cnpq.br/9052207260053937
Cotton as a crop in Brazil has undergone significant changes in production technology and geographical location in recent years. Cultivation has shifted from traditional producing zones in the southeast of Brazil and the south region of the State of Goiás to the cerrados of the country's central-western region and the western part of Bahia. These technological changes were triggered by the adoption of exotic cultivars (American and Australian), with higher yield potential, better fiber quality, but also greater nutritional requirements. During this process, more demanding cultivars were consequently adopted, concurrently with the occupation of soils of lower natural fertility. During this period, a productivity increase in excess of 100% was verified. The conjunction of these factors has disorganized the fertilization recommendation practices adopted for this crop, since they were no longer adequately supported by the existing calibrations, generated under different soil conditions and at a different technological level. The use of fertilizers was then greatly intensified, in a most disorderly manner. Within this context, potassium was the nutrient whose use increased the most, due to the specific characteristics of this nutrient on the plant's metabolism and to its high degree of absorption by cotton plants. The potassium fertilization of cotton in the cerrados has therefore been performed in the various producing areas with great variation in rates and application modes, from total applications in the soil at pre-planting, to split applications in the soil, to supplementary foliar applications, still without the proper support from current experimental results. In this work, we evaluated the effect of combined soil and foliar applications of potassium on the productivity and quality of ginned cotton, under the cerrado conditions of the State of Goiás, by the installation of two experiments, combining different potassium rates in both application modes, organized in random blocks with split-plots. One assay was installed in Ipameri, with the application of five treatments to the soil (0, 60, 120, 180, and 240 kg ha-1 K2O ha-1) combined with four foliar treatments ( 0; 7.2; 14.4; and 21.6 kg K2O ha-1). Another assay was installed in Santa Helena de Goiás, in which four potassium levels were evaluated in the soil (0, 80, 160, and 240 kg K2O ha-1), combined with foliar rates similar to those used in the Ipameri assay. Significant productivity gains were observed for the soil applications in both assays, and for the foliar applications in the Ipameri assay. No interactions were observed between application modes. Also, no significant potassium fertilization effects were observed on the technological quality of the fiber.
Caracterização biológica e fisiológica de populações de Sclerotinia sclerotiorum e avaliação da resistência genética em cultivares de soja
(Universidade Federal de Goiás, 2012-06-29) GARCIA, Riccely ávila; CUNHA, Marcos Gomes da; http://lattes.cnpq.br/2006008625763742
The soybean (Glycine max L. Merril) is the main cultivated species on the country, having an average productivity of 3,106 kg.ha-1 in an area of 24.2 million hectares, giving to Brazil the second place in world production. Among the factors that limit the yield, the profitability and the successful production of this legume, diseases are a highlight. Among them, the white mold, caused by Sclerotinia sclerotiorum (Lib.) of Bary, is gaining importance in the soybean fields on the Brazilian Cerrado . The control of this disease is being considered difficult due to the absence of resistant cultivars, fungus survival in soil during long periods, range of hosts, large number of ascospores produced by apothecium and their fast dissemination on relatively long distances from the source and survival in seeds on mycelial dormant form or sclerotia, contaminating the batches. This work had the aim to study the genetic variability of S. sclerotiorum populations; evaluate the aggressiveness of isolates in soybean culture; evaluate the sensitivity of isolates to fungicides, temperatures and light regime; select an inoculation method of S. sclerotiorum in soybean plants, efficient and practical and; characterize soybean cultivars for reaction to S. sclerotiorum. The experiments were conducted on the Escola de Agronomia e Engenharia de Alimentos da Universidade Federal de Goiás . The collection of isolates was obtained by collecting sclerotia in soybean plants in eight municipalities of the Brazilian Central Region, Silvânia GO, Anápolis GO, São Miguel do Passa Quatro GO, Água Fria GO, Montividiu GO, Chapadão do Sul MS, Uberlândia MG and Patrocínio MG. The tests of mycelial compatibility were performed in MPM (Modified Patterson s Medium) and in PDA (Potato Dextrose Agar) medium, having the mycelial reactions of compatibility and incompatibility evaluated seven days after incubation. Analyzes of mycelial compatibility were performed in each sampled municipality, with a number of 25 isolates, as well as among groups of mycelial compatibility of each municipality, totaling 31 isolates. To evaluation of aggressiveness, 21 isolates representing each group of mycelial compatibility, found in each studied locality, were inoculated by the tip method on the petiole in the cultivars M-SOY 7908 RR and BRSGO 7760 RR. The evaluations of lesion length on stem were made three and seven days after inoculation. The same 21 isolates used on aggressiveness experiments were evaluated for sensibility to fungicides fluopyram, boscalid, thiophanate methyl, carbedanzim, dimoxystrobin + boscalid, procymidone and fluazinam. Those isolates were also evaluated for sensibility on temperatures 10oC, 15oC, 20oC, 25oC and 30oC, in light regime conditions of 12 hours and continuous darkness. For selection of a inoculation method both efficient and practical, four inoculation methods were used in soybean cultivars M-SOY 7908 RR and BRS 7760 RR using only one isolate. The characterization of soybean cultivars regarding reaction to S. sclerotiorum was made by means of an aggressive isolate, selected on aggressiveness experiments, and by the tip method. In this experiment forty cultivars were evaluated in totally randomized design with 3 repetitions. In intrapopulation analysis, was verified that the genetic variability in S. sclerotiorum was low, while in interpopulation analysis, eight compatibility groups were found, one of the groups more aggressive than the other ones. There was significant difference among isolates for the aggressiveness in the two cultivars, being the M-SOY 7908 RR cultivar the most susceptible. The isolates were highly sensible to fungicides boscalid, carbendazim, dimoxystrobin + boscalid, procymidone, fluopyram and fluazinam, only the isolate SSUB 18 was moderately sensible to the fungicide fluopyram. Most of isolates had insensibility to the fungicide thiophanate methyl. The best temperature for mycelial growth of isolates was 25oC, regardless the light regime. The tip method of inoculation in petiole was efficient and practical for characterization of soybean cultivars for their reaction to S. sclerotiorum. There is varietal difference among soybean cultivars for resistance to white mold, being cultivars BRSGO 8460RR, BRSGO Ipameri and P98Y11 the most resistant ones, on the present study conditions.

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