Abstract in English:ABSTRACT. The present study aimed to review the advances in the production of temperate fruits to determine future research directions that improve production in the tropics. Temperate fruits are no longer only produced in regions characterized by a cold winter period. These fruits are also produced in the sub-tropical and tropical regions characterized by mild winter or even the absence of chilling conditions often required by the tree to break dormancy. Currently, temperate fruit production is possible in certain regions of South America, Africa and Asia that are near to the Equator. However, temperate tree fruit production in tropical regions requires modified techniques to overcome dormancy and allow adequate flowering, growth and productivity. The main approaches taken are the development of cultivars with low chilling requirement, chemical induction of budbreak, interruption of irrigation during the winter period, defoliation, orchard densification, and double pruning. Breeding has become a key tool in the advancement of temperate fruit growing in the tropics, especially with the development of low chilling requirement cultivars.
Abstract in English:ABSTRACT. The Discussion is the hardest section of a scientific article to write, as cognitive skills must be used to properly contextualize the findings of a study. In this article, we guide scientific writers, particularly unexperienced ones, on how to structure a Discussion section based on an article by Docherty and Smith (1999). According to these authors, a discussion should be prepared by organizing information in the following order: (a) statement of principal findings; (b) strengths and weaknesses of the study; (c) strengths and weaknesses in relation to other studies, discussing particularly any differences in results; (d) meaning of the study: possible mechanisms and implications; and (e) unanswered questions and future research. Each component of this sequence is discussed in detail with examples drawn from the literature.
Abstract in English:ABSTRACT. We investigated regression models with mixed effects using generalized linear statistics to evaluate germination data from Stevia rebaudiana (Bert) Bertoni. Estimates and validation of statistical parameters were conducted using the “gamlss” package in the R software. Generalized linear mixed effects followed the binomial, the beta-binomial and the multinomial distribution with the logit link to explain data based on the following explanatory variables: seed germinator, plastic tray position on every tier of shelves, illuminance conditions (light and darkness) and seed lots. We did not find differences in proportional responses from seed germinators, but we did find differences in the illuminance conditions, plastic tray position on the tiers of shelves in the seed germinators and seed lots. The estimates of the generalized Akaike information criterion (GAIC), Akaike information criterion (AIC), global deviance (GD) and Bayesian information criterion of Schwarz (BIC) indicate similar goodness-of-fit for the binomial and beta-binomial models. All of the models indicate that the position of the germination tray on every tier of shelves and illuminance conditions affected the proportions of normal seedlings. The seed germination in the plastic tray on the uppermost position under fluorescent day light lamps had an effect on the proportion of normal seedlings of Stevia.
Abstract in English:ABSTRACT. The present work has aimed to assess the consideration of the appropriate variation sources of the statistical model and their impacts on the conclusions plant breeding. The Value for Cultivation and Use test was conducted to assess three common locations (Lages, Ponte Serrada, and Canoinhas) and four non-common locations (Chapecó, Guatambu, Urussanga, and Campos Novos). The grain yields of six bean genotypes were evaluated in order to represent the imbalance between the common and non-common locations. The statistical analysis considered two situations: i) union of the location factors and cultivation years, with a single variation source called environment and ii) decomposition of the mean square values of the two factors, location and year. According to the simplified analysis (environmental variation source), the F test for the genotype factor was highly significant (p = 0.0006). On the other hand, the hypothesis test for the genotype factor was not significant (p = 0.7370) when the decomposition of mean squares was used. The simplified analysis presents some erroneous points, such as the use of a mean residue to test the hypothesis of the genotype factor, since this factor is composed of several sources of variation, and there is no exact F test. However, approximate F tests can be obtained by constructing linear combinations of average squares. This fact notes the relevance of considering the appropriate sources of variation within the statistical model, with a direct impact on the conclusions and recommendations of cultivars with superior performance.
Abstract in English:ABSTRACT. Statistics is the main science by which researchers validate the results of scientific work, and the choice of an inadequate statistical method may lead to conclusions that are considered questionable by reviewers. This study had the objective of describing the characteristics of the statistical methods used in the papers published in Acta Scientiarum. Agronomy from 1998 to 2016 as part of a a critical analysis of the journal to pinpoint possible failures in the application of these methods. All scientific articles (n = 1,237) published in the journal were surveyed, of which 54.1% addressed areas of crop production. The mean comparison methods were the most commonly used (75.5%) and, consequently, they represented the highest proportion of errors (60.8%) of the authors in the journal.
Abstract in English:ABSTRACT. The aim of this study was to model the individual height and volume of eucalyptus wood in two integrated crop-livestock-forest systems (ICLF1 and ICLF2) in Campo Grande, a city in the state of Mato Grosso do Sul, Brazil. Classic nonlinear growth models were adjusted for height (Logistic, Gompertz, Richards, Weibull, Van Bertalanffy, Brody, Mitscherlich, and Chapman and Richards) and volume (Shumacher-hall nonlinear, Takata, Honner, Logistic, Gompertz, and Weibull) in two structural arrangements: ICLF1, with a spacing of 14 x 2 m and density of 357 trees ha-1, and ICLF2, with a spacing of 22 x 2 m and density of 227 trees ha-1. Diameter at Breast Height (DBH) measurements were performed in 100% of trees, with measurements of the total height of some individuals and a rigorous scaling procedure in diameter classes. According to the calculated value of Student's t-test, there was no significant evidence that DBH and the average height of the trees were different between ICLF1 and ICLF2. Based on the Akaike information criterion (AIC), the corrected Akaike information criterion (AICC) and the Bayesian information criterion (BIC), the Richards model was selected to estimate heights and the Takata model was selected to estimate the volume.
Abstract in English:ABSTRACT. GenomicLand is free software intended for prediction and genomic association studies based on the R software. This computational tool has an intuitive interface and supports large genomic databases, without requiring the user to use the command line. GenomicLand is available in English, can be downloaded from the Internet (https://licaeufv.wordpress.com/), and requires the Windows or Linux operating system. The software includes statistical procedures based on mixed models, Bayesian inference, dimensionality reduction and artificial intelligence. Examples of data files that can be processed by GenomicLand are available. The examples are useful to learn about the operation of the modules and statistical procedures.
Abstract in English:ABSTRACT. The identification and interpretation of discrepant observations in sensory experiments are difficult to implement since the external effects are associated with the individual consumer. This fact becomes more relevant in experiments that involve blends, which scrutinize coffees with different qualities, varieties, origins, and forms of processing and preparation. This work proposes a statistical procedure that facilitates the identification of outliers while also evaluating the discriminatory powers of a sensory panel concerning the differentiation of pure blends and coffees. For this purpose, four experiments were performed that tested coffees with different qualities and varieties. The results suggest that the statistical procedure proposed in this work was effective for discriminating the blends relative to the pure coffees and that the effects of the concentrations and types of processing did not interfere with the statistical evaluations.
Abstract in English:ABSTRACT. Estimation of reference evapotranspiration (ETo) is very relevant for water resource management. The Penman-Monteith (PM) equation was proposed by the Food and Agriculture Organization (FAO) as the standard method for estimation of ETo. However, this method requires various weather data, such as air temperature, wind speed, solar radiation and relative humidity, which are often unavailable. Thus, the objective of this study was to compare the performance of multivariate adaptive regression splines (MARS) and alternative equations, in their original and calibrated forms, to estimate daily ETo with limited weather data. Daily data from 2002 to 2016 from 8 Brazilian weather stations were used. ETo was estimated using empirical equations, PM equation with missing data and MARS. Four data availability scenarios were evaluated as follows: temperature only, temperature and solar radiation, temperature and relative humidity, and temperature and wind speed. The MARS models demonstrated superior performance in all scenarios. The models that used solar radiation showed the best performance, followed by those that used relative humidity and, finally, wind speed. The models based only on air temperature had the worst performance.
Abstract in English:ABSTRACT. The recent exploration of autonomous robotics tasks in agro-industry has permitted the integration of theories of artificial vision and mobile robotics with tasks in precision agriculture. Artificial vision allows for the classification of weeds and crops from images of plantations. With 3D-image processing systems, the location of the weeds is determined, and then the movement of the tool responsible for eradication is proposed. This article presents the solution for finding weeds within a crop field using classifiers and the integration of a 3D-vision system that builds a point cloud featuring the plants to safeguard, the weeds and the free space using Zed technology. With this information, search techniques such as A* (A star) and RRT (Rapidly exploring Random Tree) are used to determine the trajectory that the weed-removal tool must follow. The last feature is an integral part of an XYZ-positioning system, and this is part of a mobile robot dedicated to precision agriculture tasks.
Abstract in English:ABSTRACT. The leaf area index (LAI) is relevant in studies of phenomena at different scales, such as for the leaf to canopy scale and the calculation of the extinction coefficient of photosynthetically active radiation (kPAR), providing input for the parameterization of physiological basis models. The objective of this work was to verify the variation of the LAI and the coffee kPAR subjected to different drip irrigation levels (130, 100, 70, and 40%) and to compare the data obtained from radiation bar linear sensors (SunScan) in the plants that received full irrigation with the values found by other LAI estimation methodologies. The study was conducted in Piracicaba, São Paulo State, Brazil, using the species Coffea arabica cv. Red Catuaí IAC 144; a drip irrigation system was adopted, with the irrigation controlled by tensiometry. The mean LAI values were higher in the L130 (irrigation level of 130%) and L100 (irrigation level of 100%) treatments than those with deficit irrigation depths. The mean kPAR values were lower for the L130 and L100 treatments than the values found in the deficit irrigation depth treatments. When comparing SunScan to other methodologies, the mean error (ME) and absolute mean error (AME) were high.
Abstract in English:ABSTRACT. New grain drying techniques have been improved to reduce post-harvest losses. The electric air dehumidifier (UTA 60®) is an example; it was installed at the ELLITT Seed Company for drying soybean seeds (TEC 7849) with random sample collection (DIC). Our objective was to evaluate the immediate and latent effects of the dehumidified air on the vigour of the seeds. Our vigour analysis method was based on the Rules for Seed Analysis (RAS), and our results showed an immediate significant difference in seedling percentage, but the germination level did not have an effect at 5% (Dunnett's test). In latent effects, at 5% (Tukey test), there was a reduction in the germination percentage and emergence rate, but it was not possible link such variations to the drying process. The germination potential was classified as "highest vigour", and it was possible to conclude that dehydrating drying air with UTA constituted a method capable of maintaining seed quality and germinative vigour.
Abstract in English:ABSTRACT. Orange rust caused by the fungus Puccinia kuehnii greatly affects sugarcane and causes millions of tons of losses in production. This condition was first reported in Brazil at the end of 2009. The disease is currently present in most of the countries that produce this crop. The aim of this research was to develop risk maps of P. kuehnii infection using temperature and relative humidity data, provided by 389 automatic weather stations throughout the country. A spatial distribution analysis was carried out to assess the number of daily hours of favorable conditions for spore germination in each region. In the central-south region, where the main sugarcane producing states are concentrated, two distinct periods were observed during the three years studied. Higher favorability occurred from October to April, and lower favorability occurred from May to September. The opposite relation was observed on the coast of the north-eastern region, where conditions were more favorable to the disease from May to September. The validation data were confirmed by the results of Pearson’s correlation between sugarcane orange rust infection under field conditions and the proposed maps. In conclusion, risk maps obtained using data from automatic weather stations could contribute to the monitoring of the risk of infection by sugarcane orange rust.
Abstract in English:ABSTRACT. Natural biological control is an important alternative for the control of insect pests using natural enemies that occur naturally in agroecosystems. The potential of these insects can increase when they are adequately managed. Thus, the objective of this study was to quantify the populations of natural enemies in soybean cultivars with different growth habits planted in different arrangements. The experiment consisted of eight treatments: four planting arrangements and two soybean cultivars, with four replicates. The populations of natural enemies were evaluated from the vegetative stage V3 to crop harvest using a shaking-cloth. A population survey of the beneficial arthropods present on the soil surface was performed in the reproductive stages R2 and R3 with the installation of modified pitfall traps. The main natural enemies that occurred in the culture were Class Arachnida, Order Heteroptera, Order Hymenoptera, Order Coleoptera and Order Dermaptera. The populations of the natural enemies assessed using the shaking-cloth did not show significant differences. However, in the evaluations with the modified pitfall traps in the reproductive stage R3 in the crossed arrangement, the populations of the Coleoptera and Dermaptera orders were higher in the determinate cultivar than in the indeterminate cultivar.
Abstract in English:ABSTRACT. Triazole fungicides have not been effective for managing the wheat blast disease in Brazil. A broad analysis across six geographical populations of Pyricularia graminis-tritici in central-southern Brazil indicated a high level of resistance to triazole fungicides. Since P. graminis-tritici is also associated with others poaceous species, here, we analyzed whether triazole-resistant isolates of the blast pathogen could be recovered from other poaceous hosts that are invasive of sprayed wheat fields. In addition to P. graminis-tritici (Pygt), we also evaluated the levels of sensitivity of three other grass-associated blast pathogens, which included P. grisea (Pg), P. pennisetigena (Pp), and P. urashimae (Pu). Resistance to the triazole fungicides tebuconazole and epoxiconazole was assessed phenotypically based on EC50 values and molecularly by analysis of the presence of mutations in the CYP51A gene, which encodes for the target enzyme 14-alpha-demethylase. We detected triazole-resistant Pyricularia spp. (Pg, Pp, Pu and Pygt) that is associated with Avena sativa, Cenchrus echinatus, Chloris distichophylla, Cynodon sp., Digitaria horizontalis, D. sanguinalis, Panicum maximum or Urochloa spp. The major outcome from our study was the evidence that invasive poaceous species from wheat fields could be an important source of triazole resistant fungal inoculum for the initial phases of the wheat blast epidemics.
Abstract in English:ABSTRACT. Waterlogging stress is one of the abiotic factors which causes damage to crops affecting yield components and grain quality of wheat and barley. On the other hand, Fusarium poae is one of the most common Fusarium species isolated from wheat and barley. The aim of this study was to evaluate the effects of waterlogging and F. poae on disease parameters, yield components and grain quality of durum and bread wheat and barley. The experiment was carried out using pots under greenhouse conditions. Four treatments were applied: control/control (W0F0), control/F. poae (W0F1), waterlogging/control (W1F0) and waterlogging/F. poae (W1F1). The results showed that incidence, severity and FHB index of F. poae were higher in W0F1 compared to W1F1 suggesting that waterlogging treatment would be generating no favorable conditions for fungal growth. Therefore, yield components and grain composition and quality were significantly affected by the Fusarium presence and waterlogging treatment which could induce changes in parameters mainly related to the industrial quality of wheat and barley. These results highlight the behavior of wheat and barley under the combination of abiotic and biotic stress.
Abstract in English:ABSTRACT. The Brazilian popcorn has low genetic variability and the successful development of advanced lines, new popcorn cultivars with high grain yield (GY) and expansion volume (PE) is dependent on parental selection and precise determination of heterotic groups. The aim of this study was to evaluate genetic variability and identify heterotic groups in synthetic populations of popcorn, using diallel crosses. Thus, nine synthetic populations were crossed using complete diallel scheme. The GY and PE traits of 36 hybrids and reciprocals were evaluated in a randomized complete block design with 72 treatments and two replicates in two years. The effects of non-additive genes were the most important in the genetic control of these traits, indicating a favorable situation to produce hybrids. The reciprocal effect is mainly due to non-maternal effects for GY and PE. The highest GY values were obtained for the 02 x 08, 04 x 09, 05 x 09, and 01 x 09 crosses and the highest PE were obtained for the 07 x 01 and 03 x 04 crosses. The exploitation of synthetic populations from S3 lines can be an alternative to increase the genetic variability for grain yield and popping expansion in popcorn breeding programs.
Abstract in English:ABSTRACT. This study presents self-organizing maps (SOM) as an alternative method to evaluate genetic diversity in plant breeding programs. Twenty-five genotypes were evaluated in two environments for 11 phenotypic traits. The genotypes were clustered according to the SOM technique, with variable topology and numbers of neurons. In addition to the SOM analysis, unweighted pair group method with arithmetic mean clustering (UPGMA) was performed to observe the behavior of the clustering when submitted to these techniques and to evaluate their complementarities. Genotype ordering according to SOM was consistent with UPGMA results, evidenced by the basic structure of UPGMA groups being preserved in each group of the maps. Regarding genotype arrangement and the group neighbors, maps involving five neurons presented inferior organization efficiency compared to the six-map arrangements in both environments. It was observed that the organization pattern among the rice genotypes evaluated by the maps was complementary to the UPGMA approach, as observed in all scenarios. It can be concluded that self-organizing maps have the potential to be useful for genetic diversity studies in breeding programs.
Abstract in English:ABSTRACT. This paper aims to present the features of the new soybean cultivar UFUS Milionária, which was developed by the Soybean Improvement Program of the Federal University of Uberlândia (UFU) through crossing between IAC-100 and Cristalina RCH cultivars, using the Single Seed Descent (SSD) method. UFUS Milionária is resistant to many diseases caused by the fungus, bacteria, and virus. In addition, it also has been proved well-adapted to many Brazilian states, showing high yield even under water deficit conditions and Asian-rust infection; average yield was 4,451 kg ha-1 in 2015/16 growing season.
Abstract in English:ABSTRACT. Canonical correlation analysis allows conclusions to be drawn about the occurrence and magnitude of associations between two groups of characteristics. This study estimated the magnitude of association and interdependence between two trait groups of clones of two varieties of Vitis vinifera grapes. The study was based on the mean data of eight characteristics from two experiments to test the performance of these clones: the first experiment provided data from seven clones of Cabernet Sauvignon, which evaluated in the northern San Joaquin Valley, California, United States, and the second data set was from six clones of the Chardonnay variety, which were evaluated in the Napa Valley, California, United States. The canonical correlations among the two varieties were significant, indicating that the two groups of characteristics were related or not independent. The quality and quantity of the raw material required for fine-wine production were inversely proportional and specific to each variety. For Cabernet Sauvignon, the high number of berries per bunch and high number of bunches per plant resulted in fruits with a high °Brix level and increased pH. For Chardonnay, the increase in the bunch weight and number of berries decreased the fruit pH.
Abstract in English:ABSTRACT. The development of melon lines resistant to gummy stem blight (GSB) is an important strategy for decreasing losses caused by this disease. Thus, selecting the best parents for such a goal is essential. We evaluated the general (GCA) and specific (SCA) combining abilities of lines and accessions to guide the selection of the most promising parents to develop GSB-resistant lines. Six genotypes representing two groups (group I - susceptible: group II - resistant) were crossed in a partial diallel mating design. The genotypes were evaluated for disease expression using a rating scale from 0 (resistant) to 4 (susceptible). Estimates of GCA were negative and significant for the accessions PI 420145 and PI 482398, which can be suggested for crosses aimed at obtaining melon lines resistant to GSB. There is a reciprocal effect for the resistance of melon genotypes to Didymella bryoniae, especially when PI 482398, PI 420145, and PI 140471 are crossed with JAB-20. Such results indicate that maternal effects may be involved in the resistance to gummy stem blight.
Abstract in English:ABSTRACT. The aim of this study was to obtain information for the genetic improvement of kale through repeatability and phenotypic stabilization studies and to compare methodologies that represent the reliability of the estimated parameters. Thirty-three half-sib progenies were evaluated in a randomized block design with three replicates and six plants per plot. Eight harvests were evaluated in terms of the yield of fresh leaves, number of shoots, number of leaves and average mass of leaves. Then, a phenotypic repeatability and stabilization study was performed, estimating the genetic parameters σ2a, σ²g, σ²e, and the coefficient of environmental variation and repeatability using the frequentist and Bayesian methodologies. To evaluate the reliability of these estimates, intervals were obtained using the frequentist, Bayesian and bootstrap methods. It was verified that the reliable selection of progenies of half-sib of kale can be achieved in four harvests that were realized between 95 and 170 days after planting. It was observed that the frequentist and Bayesian methodologies are better suited to obtain reliable estimates of the genetic parameters evaluated, as the last one provided smaller amplitudes for the obtained intervals. The bootstrap methodologies are not recommended for phenotypic repeatability and stabilization studies in kale.
Abstract in English:ABSTRACT. Maize breeding programs conduct multi-environment trials every year to assess the performance of new cultivars in pre-releasing tests. The data are combined across sites and seasons to perform a joint analysis in order to obtain information that will help breeders to select the best cultivars for different environments. Beyond this, it is essential to understand the different factors that can hamper the selection and genetic progress (i.e., genetic variability, selection intensity and genotype-by-environment interactions). In this study, the genetic progress (GP) was estimated and the adaptability and stability of 81 maize genotypes were evaluated in a series of trials for the value of cultivation and use (VCU) between the 2010/11 and 2014/15 growing seasons. The genotypes were composed of open-pollinated varieties, topcross hybrids, intervarietal hybrids, and single, double and three-way cross hybrids and were assessed in 117 environments in the central region of Brazil, from which 22 presented environmental stresses. For grain yield, an annual GP of 331.5 kg ha-1 was observed, thus showing efficiency in the selection of superior cultivars. Additionally, it was observed that some low-cost seed cultivars showed yield potential, adaptability and stability estimates that were compatible with commercial hybrids, thus making them quite attractive for cultivation in environments with or without abiotic stresses.
Abstract in English:ABSTRACT. There is a demand for barley cultivars that are suitable for the malt industry as well as genotypes that are stable and better adapted for irrigation in the Cerrado. This study aimed to estimate the genetic parameters by assessing 69 barley genotypes from different countries, from 2012 to 2014, under irrigation in the Cerrado. Six agronomic characteristics were assessed: grain yield, plumpness kernel, thousand seeds weight, plant height, degree of plant lodging and days to heading. Analysis of variance, cluster test and phenotypic, genotypic and environmental correlations were performed. Significant effects were observed for genotypes, years and the G x E interaction. High values of broad-sense heritability (> 86%) were found for all the characteristics, which enabled direct selection. The Colombian accession MCU363PI402112 stood out for its agronomic characteristics. Genotype selection based on the phenotypic evaluations was possible due to their good experimental accuracy and precision. Precocious genotypes with high grain yields and homogeneous grain sizes were selected. Due to the environmental influence on the grain yield, additional studies concerning the components of yield in this environment are necessary to facilitate the selection of more productive genotypes.
Abstract in English:ABSTRACT. The objectives of the present study were to construct a cowpea genetic map using the F2 population resulting from the cross IC-1 x BRS Marataoã, based on single nucleotide polymorphism (SNP) markers, and to map the cpi gene, with additional reference to introgression with the consensus map of species, aiming to identify markers for assisted selection to develop more efficient cultivars for BNF. The parents and 89 F2 plants were genotyped with 51,128 SNP markers, of which 910 polymorphic markers were used to construct the map. The results revealed 11 linkage groups, with an average of 82 markers per chromosome and average distance of 1.26 cM between markers. Recombination analysis of the SNPs indicated that markers 2_12850 and 2_00188, located in linkage group 11, flanked the cpi gene at a distance of 6.7 cM and 5.64 cM, respectively. The introgression of linkage group 11 with the cowpea reference map revealed short distances (from zero to 0.6 cM) for these markers, indicating a strong association with the cpi gene. The constructed map and cpi mapping provide basic information that can assist the genetic breeding of more efficient cowpea plants for BNF by marker-assisted selection.
Abstract in English:ABSTRACT. Since 2001, the disease known as 'guava decline', resulting from the interaction between the phytonematode Meloidogyne enterolobii and the fungus Fusarium solanie, has caused direct and indirect economic losses to the entire guava production chain. Given the lack of sources of resistance in guava genotypes, interspecific hybrids of Psidium spp. were obtained for resistance to the nematode M. enterolobii. To classify the level of resistance of the interspecific hybrids, we evaluated the plant classification methodologies proposed by Oostenbrink (1966) and Moura and Régis (1987). Estimates of genetic parameters were obtained using the REML/BLUP approach. Interspecific hybrids resistant to M. enterolobii were selected that can be used as rootstocks or in new crosses for the development of the guava breeding program.
Abstract in English:ABSTRACT. The aim of this study was to verify the resistance of tomato genotypes (crossed with Solanum galapagense) to the green peach aphid, Myzus persicae, and the association of this resistance with glandular trichomes. Leaf trichomes were quantified for seven F2 genotypes of the BPX-486 population derived from crossing S. lycopersicum ‘TOM-684’ and S. galapagense accession ‘LA-1401’, for the commercial controls ‘TOM-584’ and ‘Santa Clara’, and for the accession ‘LA-1401’. After this evaluation, the genotypes were subjected to two nonpreference resistance tests of the green peach aphid in the laboratory, one with choice and the other without choice. Five genotypes (BPX-486-17, BPX-486-62, BPX-486-10, BPX-486-46, and BPX-486-08) and the accession LA-1401 exhibited a high density of type IV glandular trichomes and a lower mean number of nymphs and adults of M. persicae than two genotypes (BPX-486-313 and BPX-486-383) and the controls with a low density of glandular trichomes, in all the evaluations of both tests. Significant negative correlations between the density of type IV glandular trichomes of the tomato genotypes and the preference of M. persicae were found, which confirms the association between this type of glandular trichome and resistance to M. persicae in tomato genotypes.
Abstract in English:ABSTRACT. The objective of this work was to estimate the general combining ability of partially inbred lines under high and low nitrogen (N) conditions and to select promising lines to obtain high yields for both conditions. Fifty-five partially inbred S1 progenies were evaluated using the top-cross method, where the lines were crossed with two testers. The 110 top-cross hybrids were evaluated for grain yield during the off-season of 2012 at two sites in the Brazilian Midwest. Partial diallel analysis was performed with the adjusted means of each of the individual analyses of the top crosses. The combining ability of partially inbred lines and testers as well as their interaction with N levels, was estimated for each site. The coefficient of concordance among 15 partially inbred lines selected by the highest general combining ability estimates for each N level was 0.60. The S1 lines 39, 11, 41, 55, 38, 37, 6, 8, and 14 were selected at both N levels. This indicates that these lines can be used to identify ideal hybrids for growing in the off-season in the Brazilian Midwest.
Abstract in English:ABSTRACT. Modifications were made in the PCR conditions aiming to overcome the problem of non-amplification of the Xanthomonas phaseoli pv. manihotis (Xpm) fragment, using the primer pair XV / XK described in the literature. The objective of this study was to propose changes in the primers already described (XV / XK_MOD) and validate the use of these new primers in identifying Xpm. The validation procedure was carried out with the primer pair XV and XK_MOD, using different strains of Xpm, other plant pathogenic and endophytic bacteria genera and one isolate of X. phaseoli pv. passiflorae. As a control, additional reactions were conducted in multiplex with the universal primers for the 16S rRNA gene of the bacteria together with XV / XK and XV / XK_MOD. Using the forward primer (XV) described in the literature together with the modified reverse primer (XK_MOD), it was possible to achieve amplification from DNA extracted from in vitro cultures and from infected tissue, but no amplification was noticed for the primer pair described in the literature, confirming the effectiveness of the proposed modification.
Abstract in English:ABSTRACT. The flooded environment brings about injuries to soybeans that vary depending on the adaptation ability of the genotype. Oxygen deprivation promotes the induction of the expression of genes related to glycolysis and fermentation pathways to maintain energy metabolism and, in addition to reducing-power consuming processes, act in the formation of adaptive structures and the maintenance of the redox status of the plant. The aim of this work was to evaluate the relative expression of genes related to soil flooding response in two contrasting soybean cultivars. Soybean plants of the sensitive (BRS 154) and tolerant (I27) cultivars at the V1 development stage were submitted to the flooding and control conditions (without flooding) for 0, 24, 48, and 96 hours. The relative expression of genes associated with flooding, including enolase (ENO), alcohol dehydrogenase 1 (ADH1), alanine aminotransferase 2 (ALAT2), hemoglobin 1 (GLB1), LOB41 domain-containing protein (LBD41), xyloglucan endotransglycosylase (XETP) and ascorbate peroxidase (APX2), was evaluated by means of RT-qPCR. The relative expression, in general, increased with flooding, especially in the root tissue. Cultivar I27 responded positively as observed by the expression of the maintenance genes of energy metabolism, structural changes and detoxification, suggesting the presence of three tolerance mechanisms in the flooding response.
Abstract in English:ABSTRACT. Inoculation of corn with diazotrophic bacteria reduces the need for nitrogen fertilization and mitigates environmental contamination risks due to the bacteria’s biological nitrogen-fixation capacity. The aim of the present study was to evaluate the effect of corn seed inoculation with Azospirillum brasilense under different nitrogen levels and post-grazing residual heights. The experiment was performed in two growing seasons and conducted in an integrated crop-livestock system for the 2014/15 and 2015/16. A factorial randomized block experimental design with sub-divided plots and three factors. The main plots varied in post-grazing residual height (0.10, 0.20, 0.30 m, continuous grazing, or no grazing), the subplots varied in inoculation (with or without seed inoculation), and the sub-subplots varied in nitrogen level (0, 75, 150, 225, or 300 kg ha-1 of N). The higher post-grazing residual height associated an A. brasilense and nitrogen fertilization resulted in increased corn biomass and production and yield. At the 300 kg dose of N, the highest grain yield was obtained under different post-grazing heights (10.15 Mg ha-1) and in the absence of the bacterium (10.00 Mg ha-1). Azospirillum brasilense helps plant growth and yield but does not replace the effect of N fertilization.
Abstract in English:ABSTRACT. Inoculation with nitrogen-fixing bacteria (Bradyrhizobium) is an indispensable technology to increase the productivity of the soybean crop. The objective of this study was to evaluate the viability of the inoculation with Bradyrizobium bacteria associated with the osmoprotector coating on different pre-sowing days and the effect of different soil pH on the components of yield, nodulation and grain yield of soybean. Two soybean cultivars were used, sown in two seasons and submitted to soil pH of 5.3 and 6.5. The seeds were inoculated at different pre-sowin periods with Bradyrizobium bacteria in the presence or absence of osmoprotectants. In the cultivar NA 5909RG (pH 5.3), the seeds inoculated with Bradyrhizobium and osmoprotector, at four and seven days of pre-sowing, presented an increase of 10.8% and 8.3% of productivity, in relation to those without osmoprotector. The osmoprotector and the inoculation of Bradyrhizobium increases the number and dry mass of nodules in soil with more acidic pH. The soil of lower acidity is responsible for higher grain yield, compared to the higher acidity, when both were not inoculated. The variable with the greatest explanatory power and contribution in the variability in the data of the experiment is the grain yield.
Abstract in English:ABSTRACT. The objective was to study the processing of Vernonanthura discolor seeds, evaluating their physical and physiological qualities and defining parameters for purity analysis and determine the weight of one thousand seeds. The seeds extracted from the infructescences were processed in a blower, testing combinations of openings of the calibration valve and the side air passage. After processing, the seeds went through water content determination, germination tests, first count of the germination test, purity analysis, weight of one thousand seeds and percentage of full seeds. Compared to the control, seeds processed in a regulated blower with the calibrator valve in position 10 plus three 360° turns of side air passage obtained an approximately three-fold increase in germination and vigour and had 96% purity. We conclude that the processing of V. discolor seeds was best done by combining the rubbing of the seeds on circular sieves (1.8 and 1.6 mm in diameter) and then passage in an adjusted seed blower (calibration valve in position 10 plus three 360° turns of side air passage). The weight of one thousand seeds is 0.500 g, and the working sample for purity analysis must be 1.3 g.
Abstract in English:ABSTRACT. The present study aimed to investigate the effects of pre-storage for 24h and 48h and different modified atmosphere packaging-MAP treatments (using low-density polyethylene - LDPE) on the antioxidant compounds and the postharvest quality of ‘Douradão’ peaches under cold storage. The peaches were submitted to the following treatments: a control (no packaging or pre-storage) and pre-storage for 24h or 48h at 25ºC combined with passive MAP (LDPE 60 µm or 80 µm). After the application of the treatments, the fruits were stored at 0ºC for 30 days plus 3 days at 25ºC to simulate marketing conditions. The results showed that on the simulated marketing period, all the treatments (except for the control) reduced woolliness and internal browning. Furthermore, both pre-storage and LDPE MAP enhanced the polygalacturonase (PG) activity, the levels of phenolic compounds and the antioxidant capacity. Thus, these results suggest that the pre-storage associated with LDPE packaging increases the shelf life of peaches by up to 30 days under cold storage.
Abstract in English:ABSTRACT. Given the high demand for food worldwide, options for maximizing food production with minimum environmental impact are needed. Therefore, the objective of the present study was to evaluate the effect of silicon (Si) and methyl jasmonate (MeJA) in the vegetative development and genetic stability of rice plants, BRSMG Caravera cultivar. The treatments used were T1 - Control group (without Si and MeJA); T2 - Tween foliar; and T3 - Si drench, T4 - MeJA foliar, and T5 - Si drench + MeJA foliar. The use of Si or Si + MeJA promoted an increase in the height, relative chlorophyll index (RCI), and fresh and dry masses, in addition to a greater Si accumulation in the plants. However, there was no difference in the quantity of DNA or in the coefficient of variation (CV) among the treatments, proving the use of silicon separately or in combination with methyl jasmonate contributed to the vegetative development and did not affect the genetic stability of the plants.
Abstract in English:ABSTRACT. The aim of this study was to evaluate the physiological and biochemical changes related to desiccation tolerance loss in millet seeds. The studied points of the germination process were determined according to the seed imbibition curve of the millet hybrid ADRF6010: control (0h), 3h of imbibition, 1 and 3 mm radicle. The seeds were dried on silica gel for 72h at 20°C, followed by pre-humidification at 25°C for 24h. Seed physiological quality was evaluated by electrical conductivity and a germination test, and seed vigor was evaluated with a first germination count and a germination speed index. The experiment was performed in a completely randomized design, and means were compared by the Scott-Knott test at a 5% probability. The enzymatic systems of superoxide dismutase, catalase, peroxidase, and α-amylase, as well as the expression of heat-resistant proteins were evaluated. Enzymatic activity was quantified with the ImageJ® software. Millet seeds lost desiccation tolerance when the radicle reached 1 mm in length. According to enzymatic standards, peroxidase and α-amylase activity, as well as heat-resistant protein activity, were related to desiccation tolerance loss in millet seeds.
Abstract in English:ABSTRACT. An uneven distribution of maize plants at the sowing row can decrease grain yield. This work was carried out to evaluate the effect of an increasing nitrogen rate on maize agronomic performance under different variation coefficients of plant spatial distributions at the sowing row. The experiment was conducted in Lages, Santa Catarina State, South Brazil. Three variation coefficients (VC) of plant spatial distribution (0, 50, and 100%) were tested. At the 0 level, seeds were evenly distributed 17 cm from each other. In the other treatments with uneven spatial distributions, the distances between two neighbouring seeds ranged from 2 to 54 cm. Four nitrogen side-dress rates (0, 125, 250, and 375 kg N ha-1) were evaluated. The increase in VC of plant spatial distribution decreased the leaf area and the relative chlorophyll content of the index leaf at silking, regardless of the nitrogen rate. When the variation coefficient of seed placement was enhanced from 0 to 100%, such behaviour contributed to a decrease in the number of kernels per ear and the grain yield. Therefore, increasing the amount of N was not an efficient strategy for preventing yield losses caused by irregular plant spatial distribution at the sowing row.
Abstract in English:ABSTRACT. The production of forest species that present seedlings with exogenous dormancy is limited by low germination rates, which can be overcome by rupturing or weakening the tegument. This study aimed to evaluate the efficiency of low-cost methods of overcoming dormancy and determine the effect of storage on the seeds of Enterolobium contortisiliquum. Four storage periods were used, freshly collected seeds (0), stored for 6, 12 and 18 months, and four methods were applied, mechanical scarification and immersion in water (EI), mechanical scarification (ES), immersion in water (IM) and control (TE). We obtained the percentage values of seedling emergence (EP) and the mean emergence time (TME). Conductivity and moisture were obtained as indicators of the physical and physiological quality of seeds, respectively. Variations in moisture content and electrical conductivity during storage did not have effect on the percentage of germination. EI treatment was more efficient for overcoming dormancy than the ES was, regardless of storage time. IM and TE treatments did not lead to germination. EI was the most efficient treatment for decreasing the TME. The results indicate that alternative and low-cost methods are efficient at overcoming exogenous dormancy and thus can be used to optimize the process of seedling production.
Abstract in English:ABSTRACT. Plants are often exposed to abiotic stresses such as salinity, which represents a barrier to the cultivation of agricultural species mainly in arid and semi-arid regions. This study evaluated the development of four saccharine sorghum genotypes for tolerance to different salinity levels under greenhouse conditions. The experimental design was a randomized complete block arranged in a 5 × 4 factorial scheme, which corresponded to five levels of irrigation water salinity [electrical conductivities of 0.5 (control), 2.5, 5.0, 7.5, and 10.0 dS m-1] and four saccharine sorghum genotypes (CSF 11, CSF 15, P 76 and P 298), with five replicates. The plants were evaluated for dry mass production, leaf area, height, stalk diameter, leaf gas exchange and relative chlorophyll content. The growth and leaf gas exchange measurements of the saccharine sorghum plants were significantly affected by salinity stress. Among the genotypes, CSF 11 and CSF 15 exhibited smaller reductions in growth, whereas P 298 showed the greatest reduction. These findings show that genotype CSF 11 can be classified as the most tolerant to salt stress, and genotype P 298 is the most sensitive.
Abstract in English:ABSTRACT. Among the most relevant aspects of seed production, mechanical damage may affect seed germination and reduce health and vigor. This study introduces a noninvasive high-resolution imaging procedure for evaluating the mechanical damage to maize seeds and the effects on seed germination. Seeds with different levels of mechanical damage were evaluated using a benchtop micro-computed tomography system (micro-CT) and digital X-ray equipment. The two-dimensional transaxial, coronal and sagittal micro-CT sections were used to inspect the seed anatomy and the mechanical injuries in the internal seed tissue. Germination tests were performed using paper towel rolls (25°C for 7 days) in which the seedling length was evaluated on a daily basis, and the seedling dry biomass was measured at the seventh germination day. The micro-CT cross-sectional images allowed an efficient spatial characterization of the mechanical damage inside the seeds. On average, mechanically damaged seeds produced seedlings with a length 24% shorter and a dry biomass 65% less than that of the undamaged seeds. We concluded that the micro-CT technique provides an efficient means to inspect mechanically damaged maize seeds and allows for a reliable association with germination response.
Abstract in English:ABSTRACT. Elephantopus mollis Kunth (Asteraceae) is an aromatic medicinal species native to South and Central America with hepatoprotective, anti-inflammatory, antitumor and leishmanicidal properties. We evaluated its maturation, ideal harvest moment, processing and seed storage, aiming to contribute to the production of this medicinal plant. We collected flower capitula between 7 and 56 days after anthesis for determination of seed moisture content, seed dry matter accumulation and germination, and correlated these factors with the morphological characters of the capitula. Capitulum processing was conducted with sieves and a seed blower to evaluate the purity, 1,000 seed weight, germination and cultural value of the seeds. The germination potential of seeds stored for 18 months refrigerated and at room temperature and the correlation of these results with those of an accelerated aging test were determined. The ideal harvest moment occurs at 49 days after anthesis and can be identified in the field by the brown coloration of the interfloral bracts. Seeds with cultural value above 80% can be obtained with the use of a 0.59 mm sieve and seed blower. The seeds can be stored cold for 12 months, and the accelerated aging test allows estimation of the viability of the seeds during storage for 18 months.
Abstract in English:ABSTRACT. The production of compact plants, which are slightly lacking in vigor and as productive as conventionally sized plants, is a trend in fruit growing. The objective of this study was to evaluate the vegetative performance and fruit quality of Gulfblaze and Reubennel plums intergrafted into two peach genotypes (UFV 186 and UFV 286). The experiment was arranged in a randomized block design using a 3x2 factorial arrangement (interstocks x cultivar) with four replications and one plant per plot. The non-intergrafted treatment was considered the control. Ten fruits were collected per plot for physical and chemical analyses. The evaluations were performed in the years 2014 and 2015. The interstock UFV 286 produced Gulfblaze trees with lower height in the two years of evaluation. When using the UFV 286 interstock, the trunk diameters were 50.2% smaller in Gulfblaze and 44.25% smaller in Reubennel than the control cultivars. Intergrafting had no influence on the fruit mass of Reubennel. In general, the peach genotypes UFV 186 and UFV 286 can be recommended as interstocks for reducing plant size in the plums studied. Intergrafting had no effect on fruit quality of Reubennel plums.
Abstract in English:ABSTRACT. The effects of pulse drip, drip line position and soil mulch on water use efficiency in yields of zucchini cv. Clarinda were evaluated. The experiment was conducted in the experimental area of the Engineering Department of the Federal University of Lavras, Lavras, Minas Gerais State, Brazil, for two years. For the first year of the experiment, the experimental design was a randomized block design with a 2 x 2 x 2 factorial design (continuous and pulse drip irrigation, surface and subsurface dripping, with and without plastic mulch), with four replications. For the second year of the experiment, the design was completely randomized in a 2 x 2 x 2 factorial design with eight treatments and five replications. In relation to the position of the drip line, the subsurface drip line was installed at a 0.15-m depth, and the soil mulch was made with double-sided plastic (white/black). The results indicated that pulse drip irrigation did not affect the yield of zucchini and that soil mulch increased the yield and water use efficiency. In terms of the drip line position, the subsurface drip line increased the yield in the first year, but it had no effect on water use efficiency.
Abstract in English:ABSTRACT. Forage cactus pear is considered a xerophilic plant, so it is adapted to harsh semiarid conditions and is a forage resource of significant importance for animal production in regions that are subject to food shortage and long dry periods. We aimed to evaluate the morphometric and physiologic characteristics and water-use efficiency of ‘Gigante’ forage cactus pear under different settings of irrigation depth and irrigation intervals with saline water. The treatments included seven conditions of water application: rainfed, 5 liters of water per linear meter every 15 days; 7% reference evapotranspiration (ETo) with a 15-day irrigation interval; 15% ETo with a 7-day irrigation interval; 33% ETo with a 3-day irrigation interval; 50% ETo with a 2-day irrigation interval; and 100% ETo with daily irrigation. Likewise, the use of saline water (3.6 dS m-1) as irrigation water on forage cactus pear did not stress the crop even in the presence of salts. The treatment with saline water and 33% ETo with a 3-day irrigation interval increased the plant height, number of cladodes, cladode area index, green mass and dry matter yields of forage cactus pear.
Abstract in English:ABSTRACT. Knowledge on the dynamics of micronutrients in coffee tree assists nutritional diagnosis and fertilization management. Therefore, the objective of this study was to evaluate the concentration and accumulation of micronutrients in the leaves and fruits of Coffea canephora. The experiment was managed in crops propagated for 2.5 years in a split-plot-in-time scheme in which the main plots consisted of fertilized and not-fertilized plants, and the subplots stipulated the evaluation periods. The berries and leaves were collected every 28 days, starting from the first flowering to full maturity. The micronutrient content was determined by laboratory chemical analysis, and the accumulation of nutrients in the fruit (mg) was calculated by multiplying the dry matter of the berry (g) × nutrient concentration (mg kg−1). The results showed that fertilization infers the zinc concentration in the fruits and the concentration for manganese, iron and zinc in the leaves in the determined periods. Micronutrient accumulation curves followed the simple sigmoidal model, with accumulation increasing considerably as a function of fruit growth. Thus, fertilization based on micronutrients must be divided over stages with higher accumulation rates, considering the specific requirement of each nutrient.
Abstract in English:ABSTRACT. The current scenario of increased water scarcity is due to climate change and directly affects food production. It is thus necessary to develop strategies to mitigate the impacts of low water availability. Therefore, the goal of the present study is to evaluate the physiological behaviour of melon cultivars under water stress. The experiment was conducted in a protected environment in the experimental Submedium region of the São Francisco River Valley in the period ranging from October to December. In this study, we used the melon cultivars 'Amarelo' and 'Piel de Sapo'. The experiment was conducted in a randomized block design with three replicates that were subdivided into plots, where the plots were comprised of four irrigation rates (50, 75, 100, and 125% of crop evapotranspiration - CET), subplots were comprised of the two melon cultivars, and sub-subplots were comprised of samplings for physiological analyses (15, 30, and 45 days after transplanting). The parameters evaluated were stomatal conductance, transpiration, net photosynthesis, relationship CI/CA, and accumulated dry matter. Water stress reduced the stomatal conductance, transpiration, net photosynthesis, CI/CA, and accumulated dry matter. 'Piel de Sapo' showed a higher photosynthetic adjustment than 'Amarelo' melon due to the gas exchange behaviour of the former, and it was, therefore, more tolerant to water stress.
Abstract in English:ABSTRACT. The aim of this study was to evaluate the effect of nitrogen fertilization with and without humic acid in barley cultivars on the export of nitrogen, phosphorus and potassium grains. The experiment was performed in the city of Guarapuava, PR, during the 2015 and 2016 growing seasons. The experimental design was in RCB in factorial 5 x 2, with the following sowing fertilization (kg ha-1): 0, 100 NPK, 100 NPK+HS, 250 NPK, 250 NPK+HS and two cultivars, BRS Brau and BRS Elis. The dose of 250 kg NPK with humic substance increased the nitrogen export to barley grains, with the highest levels occurring in the BRS Brau cultivar under favorable climatic conditions. Under favorable climatic conditions, the export of phosphorus to barley grains in the agricultural crop was not influenced by the humic substance, with the highest levels occurring in the BRS Brau cultivar. The dose of 100 kg NPK with humic substance increased the export of potassium to barley grains, with the highest levels occurring in the BRS Brau cultivar regardless of climatic condition. There were correlations between nitrogen and phosphorus levels in grains and between phosphorus content and grain yield.
Abstract in English:ABSTRACT. The density and distribution of soybean plants can interfere in the plant growth stage and yield, as well as phytosanitary management of this crop. Thus, innovations in production systems must be followed by improvements in pesticide application technology. Therefore, this study aimed to evaluate the influence of soybean sowing arrangements on fungicide application technology, with or without air assistance in the spray boom, using qualitative and quantitative assessments of the spray deposits. In the experiments, a randomized block design with split plots was used. Four soybean sowing arrangements: Conventional (CO), Double row (DR), Narrow row (NR), and Crossed rows (CR) composed the main plots, and fungicide application technologies with air assistance (AA) and without air assistance (WA) in the spray boom composed the subplots, with four replications. For the assessment of spray deposits, Brilliant Blue tracer dye was used in the spray solution, and the spray coverage was evaluated using water-sensitive papers. The effects of different soybean sowing arrangements on deposits and spray coverage were limited. However, an increase in spray deposits on the lower part of the soybean plants was observed with air assistance in the spray boom.
Abstract in English:ABSTRACT. Germination metabolism of recalcitrant seeds of Araucaria angustifolia is activated in storage, which complicates the seeds conservation and utilization. This study aimed to identify the changes in the reserve metabolites of A. angustifolia seeds throughout storage in order to understand the processes of hydrolysis caused by germination metabolism. Mature seeds were harvested in southern Brazil and stored in an ambient environment and cold chamber conditions. Biochemical analyses were performed for embryos and megagametophytes from seeds stored for 0, 15, 30, 45, and 90 days. Due to seeds being in advanced germination in storage, they were evaluated at 90 days in different early developmental categories: I - seeds with mature embryos, II - seeds with embryos showing apparent elongation along the embryonic axis, and III - seeds with root protrusion. Higher contents of carbohydrate, protein, and amino acids were observed in embryos compared to megagametophytes, and these metabolites were decreased after onset of germination, especially in the embryo tissue. Mobilization of metabolites in megagametophytes would probably increase in later stages of germination. It is suggested that such alterations are not due to deterioration of reserve components, but instead are based on seed metabolism, which remains active after harvest with hydrolysis of metabolites providing energy for germination.
Abstract in English:ABSTRACT. The objective of this study was to verify the activity of invertases in Estilosantes under the influence of cultivation systems and nitrogen fertilization in two seasons. The experiment was conducted in the Xaraés area, where Estilosantes was planted according to a 2 x 2 factorial scheme with two cultivation systems (monoculture and mixed pasture) in the absence or presence of fertilization (75 kg of N ha-1). A randomized block design with four replications was used. The neutral cytosol (Inv-N), vacuole acid (Inv-V) and cell wall acid (Inv-CW) invertase activity and reducing sugar contents in the leaves and stems were evaluated and analyzed by a 5% probability F-test. The interaction between cultivation systems and nitrogen fertilization was significant for Inv-N in the leaves in the summer, such that greater activity occurred in response to the mixed pasture system and nitrogen fertilization. Nitrogen increased the activity of the Inv-N in the stem in both periods, increased the activity of Inv-V in the leaf in the summer, and decreased the activity of Inv-CW in the fall. This cultivation system influenced the activity of Inv-N regardless of the period of the year and did not interfere with the activities of the acid invertases. The invertases did not show regular changes in relation to nitrogen fertilization.
Abstract in English:ABSTRACT. In most cases, in genetic breeding of Arabica coffee, plot size is defined in an empirical manner. It is often based only on the experience of the breeders and the availability of resources, potentially leading to a reduction in precision. Therefore, the aim of this study was to estimate the size of the experimental plot for evaluation of coffee yield. We evaluated two experiments for validation of cultivars with 12 treatments set up in a randomized complete block design with three replicates and plots composed of 50 plants. Each plant was considered as a basic unit. Estimates of ideal plot size were made by maximum curvature of the coefficient of variation, linear-plateau segmented model and by the resampling methods. We discussed the variations in the parameter estimates for different plot sizes. Divergence was seen among the plot sizes estimated by the different methodologies. Increasing the number of plants per plot led to a higher experimental precision to the point that the increase was no longer significant. The plot size recommended for evaluating coffee production is from seven to 19 plants.
Abstract in English:ABSTRACT. The productive capacity of soybeans is associated with the adaptation of the culture to the cultivation environment. Factors such as a high number of pods, the weight of a thousand grains, and grain number are essential factors in determining cultivars of high productive potential. The launching of new varieties associated with new technologies makes it necessary to know the performance of these varieties in different growing environments. This study aimed to analyze the agronomic performance of transgenic soybean cultivars under Cerrado conditions. The experimental design used completely randomized blocks; six of the twelve cultivars used RR1 technology and the remaining six used RR2BT. The cultivars were grown in five distinct locations in the southwest region of Goiás. The results demonstrated no increments in the grain yield of the RR1 or RR2BT technologies and the precocity of the cultivars also did not favor an increase in grain yield. The localities of Jataí and Rio Verde did not influence the cultivar cycle.
Abstract in English:ABSTRACT. The cotton producers from southern Mato Grosso are currently experiencing control failure with the use of the use of insecticides against the cotton boll weevil Anthonomus grandis Boheman, the main pest species of this commodity. Therefore, the present study was designed to survey insecticide resistance and the associated likelihood of control failure among boll weevil populations in the region. Ten insect populations were sampled during the 2016/2017 season and subjected to time-mortality (contact) bioassays in glass vials impregnated with dried insecticide residues at their respective label rates. The three insecticides most frequently used in the region were surveyed: the organophosphate malathion and the pyrethroids beta-cyfluthrin and zeta-cypermethrin. The survival curves showed estimates of the respective median survival time (LT50) for each combination of insecticide and insect copulation. However, there were no significant differences in susceptibility among populations. The estimates of control failure likelihood for each compound at their respective label rates also indicated negligible risk of control failure with their use. These findings are consistent with time-mortality results indicating the lack of insecticide resistant populations at the surveyed sampling sites, suggesting that the reported field control failures result from other causes such as problems with insecticide application.
Abstract in English:ABSTRACT. Agricultural species are subjected to a variety of biotic and abiotic stresses, which are the main limitations to crop production. In this context, contamination by trace elements is characterized as an abiotic stress that represents an environmental problem. Due to the physical and chemical similarities between cadmium and zinc, these elements may interact in the environment and may cause antagonistic or synergistic effects. In this way, physiological mechanisms to exclude, detoxify or compartmentalize trace elements that are in excess are crucial for plant survival when exposed to high concentrations of these elements. In this way, the aim of this study was to understand the physiological responses of Phaseolus vulgaris plants subjected to increasing doses of Cd and Zn for 21 days in different soil, Cambisol and Latosol. The activity of antioxidant enzymes, such as SOD, CAT, and APX; hydrogen peroxide content; lipid peroxidation; chlorophyll index; photosynthetic rate; stomatal conductance; and transpiration were analysed. The data obtained showed a specific behaviour of Phaseolus vulgaris plants in each soil analysed. Moreover, it was observed that interactions between both elements resulted in a synergistic effect, negatively affecting all of the parameters analysed.
Abstract in English:ABSTRACT. Soils under pastures suffer physical modifications, in greater or lesser intensity, via the action of animal trampling. Thus, the aim was to evaluate the spatial dependence of soil physical attributes under bovine trampling. The trial was performed at Roçadinho Farm, Agreste of Pernambuco, Brazil, in a 40 x 40 m paddock that was managed with continuous stocking by bovines and 12 AU ha-1 stocking rate. Soil samples were collected before and after grazing using a 6 x 6 m grid, totaling 36 sampling points. At each point, the bulk density, total porosity, moisture, soil penetration resistance at 0.00 - 0.10, 0.10 - 0.20, and 0.20 - 0.30 m depth were estimated, as was the hydraulic conductivity on the saturated soil surface. Descriptive statistics and geostatistics supported the data analysis. A normal distribution was verified for all variables, which were scored as either low or high variability in terms of the variation coefficient. The physical attributes (density, total porosity, moisture, soil penetration resistance and hydraulic conductivity) of the soil sampled presented a strong spatial dependence before and after grazing.
Abstract in English:ABSTRACT. We studied the mineralogical properties and chemical composition of different granites using energy dispersive X-ray spectroscopy coupled with scanning electron microscopy to understand the relationship between granite signatures and soil characteristics, including weathering patterns and soil fertility status. The discriminant analysis (DA) was based on soil physical and chemical properties and was used to differentiate soils developed from I- and S-type granites across contrasting climatic conditions in northeast Brazil. The DA identified the highest values of organic carbon, clay and plant nutrients as key variables to recognize soil profiles derived from I-type granites. In contrast, the greater sand contents and Al saturation distinguished soils developed from S-type granites. These results were related to the mineralogical characteristics of each granite type, such as a high percentage of silica-bearing minerals in the S-type granites. The highest concentrations of K, Ca, Mg, and P in I-type granites were found in feldspars, amphiboles, and apatite. These elements account for the majority of nutrients derived in their soil profiles. However, it seems that the harsh conditions of the humid tropical environment equalized the effect of the rocks on weathering rates-the difference in chemical index of alteration is more extreme in the dry region.
Abstract in English:ABSTRACT. In Amazonia, the main causes of deforestation are systems based on slash-and-burn agriculture. The objective of this work was to evaluate temporal changes in the soil chemical attributes after the vegetation has been slashed and burned in an area of native forest in the Western Amazon. For this study, four hectares of forest in Cruzeiro do Sul, State of Acre, Brazil, was slashed and burned. The soil in the study area was classified as Ultisol (Argissolo Amarelo Distrófico típico). Soil samples were collected over the course of one year, the first one being collected 16 hours after the burn and the others at 30, 60, 90, 150, 210, 270, and 360 days after the burn. The soil surface layers were more sensitive to fire action. Ashes from vegetation burn increased pH values, basic cations, and C values only in the first months, resulting in higher basal saturation values (V%). The practice of slash-and-burn after 12 months resulted in lower values of pH, Ca, Mg, K, and P and higher values of Al and H, as well as saturation by aluminum in the soil, indicating this practice contributes to the reduction of soil fertility.
Abstract in English:ABSTRACT. Metal concentrations in suspended sediments of one of the most polluted rivers in Brazil were measured. Concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were determined by inductively coupled plasma while Hg and As were analyzed with hydride generation flow injection atomic absorption spectroscopy. Contamination of As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn was assessed using pollution indices, ecological risk assessment, statistical multivariate techniques and comparison with sediment quality guidelines. Suspended sediments of the upstream portion of the Ipojuca River are moderately contaminated, especially with Mn and As. On the other hand, sediments of the downstream section are highly contaminated, mainly with Zn, Pb, and As. Furthermore, the mean Ei (potential ecological risk) values of Pb and As showed considerable ecological risk in the downstream cross section. The comparison of our data with sediment guideline values indicated that the concentrations of Mn and Pb in the upstream section of the Ipojuca River pose a risk to sediment-dwelling organisms, while Pb and Zn are the metals of concern in the downstream section.
Abstract in English:ABSTRACT. The relationship between soil and health is important for populations that depend on the local environment to meet their nutritional needs. This study aimed to evaluate the concentrations of major and trace elements in the soils, edible parts of crops and urine of farmers in agroecological communities. We collected samples of soil, edible parts of crops and urine of farmers and family members in 23 crop fields in agroecological communities from northeast Brazil. These samples were analyzed to concentrations of Al, As, Ca, Cr, Cu, Fe, Hg, Mg, Zn, and Pb in urine and discriminant analysis and principal component analysis were used to assess the data. Concentrations of potentially toxic elements in soils and crops of agroecosystems were below regulatory levels. Farmers living in agroecological communities present most of the essential and toxic elements in urine within the reference ranges. In general, results showed that urinary concentration of toxic elements among farmers and their families were below allowable limits, which may be due to the agroecological practices.
Abstract in English:ABSTRACT. As the fourth largest importer of olive oil and the fifth largest importer of olives, Brazil is one of the largest importers of olive (Olea europaea L.) products in the world. In recent decades, the introduction and growth of olive cultivars with lower chilling requirements in the south and southeast regions of Brazil have made olive production viable in the country. However, there is a dearth of information about the management of olive crops in Brazil, especially in relation to studies about the nutritional needs of olive trees grown in subtropical regions, which may enable advances in the productivity of this fruit. The aim of this study was to evaluate the growth, dry matter production and nutritional status of the olive tree under the effect of nutrient omissions, as well as to establish visual diagnostic parameters of nutrient deficiencies. We used a completely randomized design with ten treatments and three replicates grown in the Hoagland-Arnon nutrient solution and solutions with individual omissions of N, P, K, Ca, Mg, S, B, Fe, and Zn. The treatments that most limited the growth of olive trees were the N, Ca, and B omission treatments.