This work aimed to evaluate the influence of the sowing speed on the regularity of longitudinal distribution of maize seeds through a pneumatic metering seeder. The experimentation of 4 sowing speeds (4, 6, 8 and 10 km h-1) was performed in randomized blocks design with four replicates. The parameters evaluated were the mean distance between plants, coefficient of variation of the distance between plants, percentage of acceptable, flawed and double spacings, precision index, plant stand, initial population, mean seed deposition depth, and coefficient of variation of the seed Nadin et al.; JEAI, 37(2): 1-8, 2019; Article no.JEAI.49124 2 deposition depth. The increase in the operating speed linearly reduced the percentage of acceptable spacings, plant stand, initial population, and mean seed deposition depth. Conversely, it linearly increased the values of mean distance between plants, coefficient of variation of the distance between plants, percentage of double and flawed spacings, precision index, and coefficient of variation of the deposition depth. Therefore, the increase in the displacement speed of the tractor-seeder set reduced the regularity of the longitudinal distribution of the plants, as well as the sowing quality. Original Research Article

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.

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 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.