Search

This study aimed to identify the main fungal and phytonematode genotypes associated with the main tropical forage seeds used in integrated systems and to distinguish seeds with high physiological and sanitary quality, for which two experiments were conducted. In year 1 (2017/18 crop year), the first experiment (experiment 1) was conducted with seeds produced in the 2017/18 crop year, in a randomized open design with four configurations and four replications. In year 2 (2018/19 crop year), the study (experiment 2) was replicated with the experimental conditions of the first experiment (randomized automatic design, with four sessions and four replications), but using samples from the 2018/19 crop year. The seeds were produced in the 2017/18 and 2018/19 crop years, with the same origin, and were purchased within commercial packages. The treatments of experiments 1 and 2 were the same and consisted of seeds of Brachiaria ruziziensis and the Brachiaria brizantha cultivars Marandu, Xaraés, and BRS Piatã. The same variables were evaluated for each experiment: water content, physical purity, viability, germination rate index, first germination count, germination percentage, crop value, dormancy, accelerated aging, and incidence of fungi and phytonematodes. Cladosporium sp., Fusarium sp., Rhizoctonia sp., Meloidogyne sp., Filenchus sp., Aphelenchus sp., Aphelencoides sp., and Rotylenchulus sp. are the main phytopathogens associated with seeds of the main tropical forage species used in integrated systems. The seeds of B. ruziziensis present high physiological quality, whereas the seeds of the B. brizantha cultivar Xaraés grass present high sanitary quality

The sunflower has adaptation for cultivation in Brazilian conditions and the main product is the oil extracted from the seeds. This study aimed to verify the impacts of meteorological attributes on agronomic characteristics of sunflower genotypes cultivated as a second crop, in Mato Grosso, Brazil. The experimental design was randomized complete block design (RCBD), cultivating the two sunflower genotypes, M734 and Hélio, in three years (2009, 2011, 2012) with four replications. The agronomic characteristics evaluated were: plant height, capitulum diameter, weight of a thousand achenes, yield of achenes, oil content and oil yield. Then, water deficit and the maximum crop yield are estimated for correlation analysis between meteorological attributes and agronomic characteristics. In both genotypes studied there was a very strong correlation between plant height with evapotranspiration (r=0.99*) and very strong negative correlation (r=-0.99*) with water deficit. For mass of a thousand achenes, there was a very strong negative correlation with the maximum (r=-0.98*) and minimum (r=-0.96*) temperatures, and with evapotranspiration (r=-0.98*) in the Helio 358. In addition, effect of the water deficit on the oil yield (r=-0.98*) was verified for the same genotype. Very strong negative correlation was found between maximum temperature and oil content (r=-0.96*) in genotype M734. In sunflower cultivation in Mato Grosso, Brazil, water deficit reduces plant height, capitulum diameter and oil yield. The oil content of the achenes reduces when the maximum temperature increases, during the cultivation. For those reasons, the use of sunflower genotypes with shorter cycles and the earlier sowing could benefit the crop developing, by suiting the management, to avoid unfavorable climatic conditions that can cause reduction in production parameters.

Integrated production systems were developed to preserve productive resources and maintain the profitability of agribusiness. However, the use of seeds of low physiological and sanitary quality and the implantation of agricultural and forage crops in production fields of low sanitary quality may favor the dissemination and proliferation of phytopathogens such as fungi. Therefore, using the scientific literature, this work aimed to identify the fungi associated with the main agricultural and forage crops that cause damage to the integrated production systems of Brazilian tropical regions and their control measures. This work was based on a literature review in the Scielo, Scopus and Google Scholar databases, with data obtained between 1999 and 2019. The keywords employed were “fungus”, “tropical grass”; “agricultural crops”; “ICLS” (Integrated Crop-Livestock); and “ICLF” (Crop-Livestock-Forest) and their respective terms in Portuguese, under different combinations. For the inclusion criteria, publications (papers, books, theses, dissertations, and scientific communiqués) from 1999 to 2019 which fit the study aim were selected, both in the Portuguese and English languages. The publications that did not meet the criteria of this study and were repeated in databases were considered as exclusion criteria. The main fungi associated with forage and agricultural crops and soils of integrated systems of Brazilian tropical regions are Bipolaris sp., Curvularia sp., Exserohilum syn. Helminthosporium sp., Phoma sp., Fusarium sp., Macrophomina sp., Pythium sp., Rhizoctonia sp. and Sclerotium sp. The main methods of fungal control are the use of quality seeds, crop rotation, resistant cultivars, and chemical seed treatment.

The integrated crop-livestock system (ICLS) is a model of sustainable cultivation that allows the recovery of degraded pastures and the intensification in pasture and grain production. However, the presence of pathogens in the production fields has hampered the employment of these systems. In order to minimize or eradicate the phytonematodes in the production fields and the seeds used in CLIS, it is necessary to know the nematofauna. Based on this, this work aimed to perform a literature review describing the main forages and agricultural crops used in integrated crop-livestock systems in tropical regions, the major phytonematodes associated with these crops and their control measures. This work was based on a literature review from the Scielo, Scopus and Google Scholar databases, with data from 1999 to 2019. The initially used keywords were "tropical weeds"; "Agricultural crops"; and "ICLS" and their respective terms in the Portuguese language. From the initial results, we used the keywords "Brachiaria syn. Urochloa sp. "; "Phytonematodes"; "Millet"; "Maize"; "Panicum sp."; "Soy"; "Sorghum", and "ICLS" and their respective terms in the Portuguese language. Publications that did not meet the criteria of this study (analyzed by titles and abstract) were considered as exclusion criteria, as well as repeated works in the databases. Based on the literature, the cultivation of forages belonging to the genera Brachiaria syn. Urochloa sp. and Panicum sp., along with and soybean, maize, sorghum and millet are predominant in the ICL system of tropical regions. The phytonematodes Meloidogyne sp., Pratylenchus brachyurus, Heterodera glycines, Rotylenculus reniformis, Aphelenchoides sp., Ditylenchus sp. and Filenchus sp. cause greater severity of damage to the main cultures used in ICL. No control method can eradicate the phytonematodes. The most effective control for the studied phytonematodes is through integrated pest and disease management.

This study aimed to evaluate the bromatological traits of Brachiaria brizantha cv. Piatã submitted to different cutting heights and nitrogen (N) rates. A randomized complete block design with sixteen treatments and four replications was used. The treatments arranged in 4x4 factorial arrangement, comprised four cutting heights (8, 16, 24 and 32 cm) and nitrogen rates (0, 100, 200, 300 kg N ha-1). N rates were applied after a standardization cutting. Agronomic traits comprised number of tillers, dry mass, leaf blade pseudocolus ratio and amount of senescent material. Bromatological traits of morphological components leaf blade and pseudostem comprised crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and mineral matter (MM). In the first and second cuttings, maximum yields were obtained at 16 and 32 cm cutting heights combined with N rates of 180.5 and 230.5 kg ha-1, respectively. No interaction was observed between N rates and cutting heights. It was concluded that 16 and 24 cm cutting heights combined with N rates of 200 and 300 kg ha-1 improved agronomic and bromatological traits of Brachiaria with a better efficiency in pasture system.

The present work aimed to evaluate the correlation of the agronomic characteristics of sunflower genotypes grown for seven years in the state of Mato Grosso, Brazil, as an aid for the indirect selection of genotypes. The data were obtained from experiments conducted in the period from 2009 to 2017, in the municipality of Campo Verde, Mato Grosso state, Brazil, using different sunflower genotypes. Pearson correlation analysis was performed between the following agronomic characteristics: Initial flowering (IF), physiological maturation (PM), plant height (PH), thousand achene weight (TAW), achene yield (AY), oil content (OC) and oil yield (OY). A strong positive correlation (r = 0.75*) was observed between IF and AY, and a moderately strong positive correlation (r = 0.67*) between PM and AY. There was a negative correlation (r = -0.51*) between TAW and OC, as well as between plant height and achene yield (r = -0.32*) and oil yield (r = -0.34*). Late-cycle genotypes showed a positive correlation with achene yield and oil yield. Smaller plants favor productive parameters. Further studies and the anticipation of the crop sowing season in the second crop are suggested due to the local edaphoclimatic conditions.

The quantification of soil nematodes is of great importance for the management and evaluation of the efficiency of control methods, considering the damages caused in crops of economic interest. The present work aimed to quantify and identify plant parasitic nematodes in pasture areas in the municipality of Santo Antônio do Leverger, Mato Grosso state, Brazil. For that purpose, 25 soil and root samples were collected in four plots, consisting of the following forage grasses: Brachiaria humidicola cv. Common (Plot 1), Panicum maximum cv. Tanzania (Plot 2), Brachiaria brizantha cv. Marandu (Plot 3) and Panicum maximum cv. Massai (Plot 4). The nematode extraction from the soil and root samples was performed, followed by the quantification and identification of nematodes genera. The nematodes classified as free-living were observed in all plots, with population densities varying from 230 to 1180 specimens. The genus Pratylenchus presented the lowest population level, with 40 specimens, in the area where the Brachiaria humidicola cv. Common is cultivated. The following phytoparasitic nematodes genera were observed: Pratylenchus and Paratrichodorus associated to the Humidicola grass, and Heterodera and Criconemoides associated to the Tanzania grass.

Considering that nitrogen is the main macronutrient limiting pasture productivity, the aim of this study was to investigate the most appropriate day for nitrogen fertilization of the grasses Brachiaria brizantha BRS Piatã and Panicum maximum BRS Quênia. The experiment was conducted in a greenhouse in the city of Rondonópolis, located in the state of Mato Grosso, Brazil, using a completely randomized design. The treatments consisted of five nitrogen fertilization periods: 0; 2; 4; 6 and 8 days after defoliation. The dry mass of the leaf blade (DMLB), dry mass of stem + sheath (DMSS), dry mass of residue (DMRES) and root dry mass (RDM) were evaluated. The non-structural carbohydrate of the grass roots was also quantified. The later nitrogen fertilization after defoliation reduced DMLB (P< .01) and DMSS (P< .01) of the BRS Piatã palisadegrass, and DMRES of both grasses (P< .01). Higher levels of water soluble carbohydrates were observed when nitrogen fertilization was performed on grass cutting (day 0). Nitrogen fertilization of the BRS Piatã palisadegrass close the time of defoliation is recommended. For Quênia guineagrass, nitrogen can be applied between the cutting day and the eighth day after defoliation. For the root system, there is a higher content of water soluble carbohydrates in the BRS Piatã palisadegrass and greater accumulation of starch in the BRS Quênia guineagrass.

Data regarding the mixing of palisade grass seeds with fertilizers are scarce and contradictory. The aim of this study was to evaluate the maximum contact time without significant damage on physiological quality of Piatã grass seeds when mixed with 05:25:15 NPK fertilizer. The experiment was conducted in a completely randomized design with six treatments and four replications. Treatments consisted of six contact times of the seeds with the fertilizer: 0, 24, 48, 72, 96 and 120 hours. The variables following variables were evaluated: water content, germination percentage, first germination count, seed viability, eletrical conductivity, accelerated aging, emergence percentage and emergence speed index. Except for the water content, there was an effect of the fertilizer contact times with the seeds over all variables. There was a decreasing linear effect of the contact time of the seeds with the fertilizer for all variables, except for electrical conductivity. The average water content of 10.09% was observed. After 120 hours of the fertilizer/seeds mixture, a reduction of 36.4% was observed in germination, of 36.7% in the first germination count, of 25.0% in seed viability, and of 65.0% in the germination of seeds subjected to the accelerated aging. There was an increase of 170.0% in the electrical conductivity of the Piatã grass seeds. The minimum standard of 60% germination, viability or emergence, required for the commercialization of forage seeds, should be maintained to ensure the ideal forage population in the establishment of the crop. Based on the emergence and viability tests, the commercialization levels can be maintained by performing the fertilizer/seeds mixture up to 63 hours before sowing. After 63 hours of seed and fertilizer mixing, a reduction of the initial vigor of the seeds can be observed, although not compromising the crop establishment or causing degradation of soil. Therefore, Piatã grass seeds can be mixed with the 05:25:15 NPK fertilizer up to 63 hours before sowing.

The aim of this study was to evaluate the effects of Brachiaria seed contact time with 05-25-15 fertilizer (N-P2O5-K2O) on the seed’s physiological quality. The experimental design was a completely randomized design with four replicates. Treatments were arranged in a 5x4 factorial, being: five seeds contact times with fertilizer (0, 24, 48, 72 and 96 hours); four forages: Marandu palisadegrass, Piatã palisadegrass, Xaraés palisadegrass and Ruziziensis grass. The performed tests were: water content, germination (first count and germination percentage), tetrazolium (viability), electrical conductivity, accelerated aging, sand emergency and emergence speed index. Contact time of 05-25-15 fertilizer with Brachiaria seeds reduces linearly: Germination, emergence and emergence speed index of Brachiaria seeds; Piatã and Xaraés palisadegrass seeds viability; vigor (electrical conductivity), except in Ruziziensis grass seeds; and seeds germination of Piatã palisadegrass submitted to accelerated aging test (vigor). Piatã palisadegrass is the least recommended, among the analyzed grasses, for intercropping in simultaneous sowing.

This study aimed to evaluate the effects of the contact of Brachiaria seeds with the fertilizer 05-25-15 on the sanitary quality of the seeds. The experimental design was completely randomized, in a (2x5) factorial design, with four replications. The treatments consisted of five contact times (0, 24, 48, 72 and 96 hours) of the fertilizer with seeds of ruziziensis grass and marandu grass. After the contact times of the Brachiaria seeds with the fertilizer, the seeds from each species were separated and the following analyses were performed: water content, germination, seed health ("Blotter Test"), and accelerated aging, with later germination test and sanitary analysis of seeds. Data were analysed for variance and regression analysis at the significance level of 5% and descriptive analysis was used for the results of the sanitary analysis. The contact time reduces the incidence of pathogens in the seeds of ruziziensis grass and marandu grass treated with the fertilizer due to the salinity and acid pH of the fertilizer. The fungi related to the reduction in germination were Aspergillus sp. and Fusarium sp. The disinfestation process increased the incidence of Fusarium sp., under high internal infestation of this fungus in palisadegrass seeds.

This study aimed to evaluate the plant growth regulator application, in different doses, on priming, with and without water restriction, in corn seeds. Evaluations were carried out in two periods (0 to 30 days of storage), with treatments consisting of seeds primed in water (0.0 MPa) and polyethylene glycol 6000 solution (-0.4 MPa), with or without plant growth regulator added in different doses, plus a control group. The amount of plant growth regulator was standardized by the gibberellic acid concentration in the commercial product, adopting the doses zero, 1, 2 and 3 mg of gibberellic acid. L-1 solution. After priming, the seeds were dried in an oven with forced air circulation for nine hours, and evaluated for water content, percentage and first count of germination, percentage of abnormal seedlings and non-germinated seeds, cold test, seedling length and dry weight and vigor index. Priming with water restriction -0.4 MPa, in solution of polyethylene glycol 6000, improves the vigor; however, the addition of plant growth regulator in priming does not provide increase in corn seeds quality. Corn priming in water, regardless the addition of plant growth regulator, reduces the ability of the seeds to withstand storage. Resumo Objetivou-se avaliar a aplicação de regulador vegetal em diferentes doses via condicionamento fisiológico, com e sem restrição hídrica, em sementes de milho. Foram realizadas avaliações em dois períodos (0 e 30 dias de armazenamento), sendo os tratamentos compostos por sementes condicionadas em água (0,0 MPa) e em solução de polietilenoglicol 6000 (-0,4 MPa), com ou sem adição de regulador vegetal em diferentes doses, mais o controle. A quantidade de regulador vegetal foi padronizada pela concentração de ácido giberélico no produto comercial, adotando as doses zero, 1, 2 e 3 mg ácido giberélico. L-1 solução. Após o condicionamento as sementes foram secas em estufa, por nove horas, e avaliadas quanto ao teor de água, porcentagem e primeira contagem da germinação, porcentagem de plântulas anormais e sementes não germinadas, teste de frio, comprimento e massa seca de plântulas e índice de vigor. O condicionamento fisiológico com restrição hídrica -0,4 MPa, em solução de polietilenoglicol 6000, melhora o vigor, entretanto, a adição de regulador vegetal no condicionamento fisiológico não proporciona aumento na qualidade das sementes de milho. O condicionamento de milho em água, independente da adição de regulador vegetal, reduz a capacidade das sementes resistir ao armazenamento.

Data regarding the mixing of palisade grass seeds with fertilizers are scarce and contradictory. The aim of this study was to evaluate the maximum contact time without significant damage on physiological quality of Piatã grass seeds when mixed with 05:25:15 NPK fertilizer. The experiment was conducted in a completely randomized design with six treatments and four replications. Treatments consisted of six contact times of the seeds with the fertilizer: 0, 24, 48, 72, 96 and 120 hours. The variables following variables were evaluated: water content, germination percentage, first germination count, seed viability, eletrical conductivity, accelerated aging, emergence percentage and emergence speed index. Except for the water content, there was an effect of the fertilizer contact times with the seeds over all variables. There was a decreasing linear effect of the contact time of the seeds with the fertilizer for all variables, except for electrical conductivity. The average water content of 10.09% was observed. After 120 hours of the fertilizer/seeds mixture, a reduction of 36.4% was observed in germination, of 36.7% in the first germination count, of 25.0% in seed viability, and of 65.0% in the germination of seeds subjected to the accelerated aging. There was an increase of 170.0% in the electrical conductivity of the Piatã grass seeds. The minimum standard of 60% germination, viability or emergence, required for the commercialization of forage seeds, should be maintained to ensure the ideal forage population in the establishment of the crop. Based on the emergence and viability tests, the commercialization levels can be maintained by performing the fertilizer/seeds mixture up to 63 hours before sowing. After 63 hours of seed and fertilizer mixing, a reduction of the initial vigor of the seeds can be observed, although not compromising the crop establishment or causing degradation of soil. Therefore, Piatã grass seeds can be mixed with the 05:25:15 NPK fertilizer up to 63 hours before sowing. Made available in DSpace on 2019-07-05T00:53:30Z (GMT). No. of bitstreams: 1 MaximumcontacttimeofPiata.pdf: 257710 bytes, checksum: 26ba63d6c2def5c06ffe3bd5d60e6274 (MD5) Previous issue date: 2019