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ABSTRACT. The orange variety “x11”, which is a spontaneous mutant of the sweet orange, has a short juvenile period with early flowering. The data used in this paper are from a randomized design experiment that aimed to assess the plants' flowering characteristics when grafted onto two different varieties of lemon rootstock. The plants were pruned in each of the four seasons, and on each pruning occasion, the number of branches on each plant was counted and classified into four mutually exclusive flowering categories. The data presented large variability and many zeros. The statistical analysis included the use of generalized linear mixed models with a Bayesian approach. The results showed that flowering is not equal over the seasons, i.e., there are significant differences in the classification of the branches across the four seasons and the two varieties, with interactions between seasonal and branch effects.

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ABSTRACT. This study was carried out in an Atlantic forest remnant in Southeastern Brazil and aimed to spatially model the soil water content (SWC) and net precipitation (NP) on a monthly time scale and to assess the spatial behavior of these hydrological variables in the different seasons. NP is defined by summing throughfall and stemflow, which have been collected after each rain event and accumulated monthly. Soil moisture measurements were carried out monthly up to a depth of 1.00 m and then integrated to obtain the SWC. The exponential semivariogram model was fitted for both hydrological variables, and the goodness-of-fit was assessed by a cross-validation procedure, spatial dependence degree (SDD) and spatial dependence index (SDI). This model provided adequate performance for SWC and NP mapping according to the cross-validation statistics. Based on the SDD, both variables have been classified as a ‘strong spatial dependence structure’. Nevertheless, when the SDI was assessed, NP showed less spatial dependence, while the SWC maintained almost the same performance. Kriging maps pictured the regional climate seasonality due to higher values of both variables in spring and summer than in autumn and winter seasons. However, correlations between NP and SWC are not expressive in the studied period.

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ABSTRACT. The use of empirical agrometeorological models that can be adjusted to the climatic conditions of different regions has become increasingly necessary to improve water management in grain-producing municipalities. The aim of this work is to examine the correlation between various reference evapotranspiration (ETo) estimation methods and the standard FAO 56 Penman-Monteith method, as well as to determine correction factors, when necessary, for crop-producing municipalities in the northeast of Pará, during both the rainy and dry seasons. We compared simpler methods of ETo estimation to the FAO 56 Penman-Monteith method. For this purpose, meteorological data from Tracuateua, Bragança, Capitão Poço and Castanhal, provided by the National Institute of Meteorology (INMET), were used. The calibration of equations was performed through linear regression. The accuracy of different estimation methods was examined. The Turc, FAO 24 Blaney-Criddle and regression methods presented the best results for all statistical criteria; the Priestley-Taylor, Makkink and FAO 24 Radiation methods presented excellent results after calibration. The methods of Camargo and Hargreaves-Samani produced the worst results for all the criteria.

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ABSTRACT. This study had two objectives - firstly, to analyze the total static and dynamic capacity of agricultural storage in Paraná State, Brazil and secondly, to verify if the storage followed the growth of grain production. The study was performed by mesoregion for the 2013/2014 and 2014/2015 crop years. The methodology used was descriptive from an agricultural database of the Secretariat of Agriculture and Supply (SEAB), of the National Register System of Storage Units (SICARM), interviews were also made with agroindustrial cooperatives and official agencies. It was identified that in Paraná State there is an insufficiency of 17.75% of total static capacity of warehouses to comply with the total grain production (soybean, 1st and 2nd corn crops, and wheat). The results showed that the total dynamic capacity of warehouses is sufficient in the mesoregions of Eastern Center, Southern Center, Northern Center, and Metropolitan. Therefore, storage units vary uniformly in most municipalities, not following the growth of total grain production in the state of Paraná.

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ABSTRACT. Sheath blight, caused by the fungal pathogen Rhizoctonia solani AG-1 IA is one of the most important rice diseases worldwide. The objetives of this study was to determine the predominant reproductive system and the genetic structure of 18 rice-infecting populations of R. solani sampled from China, Japan and the Philippines, the most important rice production countries in Asia. Knowledge about the population genetic structure of the pathogen in Asia is useful in identifying sources of infection and formulating sustainable management strategies for rice sheath blight. From a total of 717 isolates, 423 unique multilocus genotypes were detected based on nine microsatellite loci. The three country populations of R. solani AG-1 IA exhibited a mixed reproductive system, which included both sexual and asexual components. A moderate degree of clonality indicated that the asexual sclerotia represent important source of inoculum. Population subdivision varied within and among countries, fitting the isolation by distance model. While no subdivision was found among populations within Japan or within the Philippines, subdivision was detected among populations within China. Historic migration indicated high influx of immigrants from Japan into Northern, Central and Eastern China populations. Southern China contributed a high number of immigrants to the populations from the Philippines.

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ABSTRACT. Identifying the behavior of natural enemies during the crop offseason is a key tool for integrated pest management. The objective of this work was to evaluate the population density of natural enemies of the plants Chloris distichophylla, Andropogon bicornis, and Erianthus angustifolium and to analyze the influence of the structural complexity of these plants on the present population. During the offseasons of 2014, 2015, and 2016, 150 plants of each species were evaluated and subdivided into different clump diameters. The species Lycosa spp., Eriops connexa, Cicloneda sanguinea, Coleomegilla quadrifasciata, Lebia concinna, and Harmonia axyridis were identified. A. bicornis was the plant with the highest population density, followed by C. distichophylla and E. angustifolium. Plants with greater structural complexities sheltered a higher population density of natural enemies.

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ABSTRACT. Fleabane (Conyza spp.) is an important weed in grain production systems and is currently one of the most problematic weeds in Brazil. An important factor related to weeds such as fleabane is the characteristic of herbicide-resistant biotypes developed under selection pressure, with multiple resistance previously detected for Conyza spp. Thus, the aim of this study was to demonstrate the multiple resistance of Conyza sumatrensis to the herbicides paraquat, glyphosate, and chlorimuron. From the F2 seeds of biotypes with suspected resistance to paraquat, glyphosate, and chlorimuron, dose-response greenhouse experiments were conducted for the three herbicides. Herbicides were applied when the plants had 6-8 leaves that were at a height of 8 cm. At the end of the evaluations, 28 days after application, multiple resistance to paraquat, glyphosate, and chlorimuron was observed, with resistance factors (RF50) for the control of 7.43, 3.58, and 14.35 and for the reduction of dry mass of 2.65, 2.79, and 11.31, respectively. All the established criteria for demonstrating new cases of weed resistance were met; thus, the first case worldwide of a Conyza species with resistance to herbicides with three different mechanisms of action was confirmed.

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ABSTRACT. The development of early and upright common bean cultivars is necessary to meet the demand of producers. The objectives of this work were to evaluate more precise experimental statistics for the selection of early and upright common bean lines and identify the traits that provide better genetic differentiation between lines. For this purpose, 156 common bean lines of different grain colours were evaluated in 23 experiments carried out in the southern region of Brazil between 1998 and 2015. The traits related to earliness (flowering and cycle) and upright plant architecture (lodging, insertion of the first pod and insertion of the last pod) were evaluated with high experimental precision by determining F-test values for genotype (Fc), heritability (h2), and selective accuracy (SA). In the experiments with Fc ≥ 2.00, h2 ≥ 49.00%, and SA ≥ 0.70, the best genetic differentiation of early common bean lines was performed by the cycle; and the best genetic differentiation of common bean lines with upright plant architecture was carried out by the insertion of the first and the last pod.

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ABSTRACT. Varronia curassavica (Jacq.) is a shrub and perennial plant native to Brazil that has therapeutic, anti-inflammatory and cicatrizing properties. The objective of this work was to study the chemical diversity of the native populations of this species maintained in the in vivo germplasm bank from Montes Claros, Minas Gerais, Brazil. The essential oils of 10 accessions analyzed in triplicate were obtained by hydrodistillation. Fifty-five compounds were detected, 46 of which were identified by GC-MS analysis. Essential oil yield ranged from 0.1 (VC-9) to 1.22% (VC-3) among the studied accessions. Three groups were formed by cluster analysis. Group A presented lower relative abundance of the compounds α-humulene (1.4%) and β-caryophyllene (8.5%). Conversely, in Group B, the most abundant compound was α-humulene (31.6%). Group C, with the greatest number of accessions, presented values of up to 6.1 and 41.2% for α-humulene and β-caryophyllene, respectively. Only two accessions (VC-1 and VC-5) presented α-humulene content lower than that recommended for phytotherapeutic production. These results, along with consolidating breeding programs, contribute to the conservation of the species.

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ABSTRACT. This work aimed to present the optimum environment number methodology and propose the optimization of the National Sunflower Trials Network, by means of the environments exclusion that do not provide loss of the environmental variability already established. Grain and oil yield data of 16 genotypes evaluated at 16 environments of the National Sunflower Trials Network, obtained from trials conducted out-of-season in 2012 and 2013 were used. An analysis was proposed to establish the optimum environment number for genotypes evaluation, based on genotype performance in the various environmental combinations. The removal or maintenance of environments in the experimental network was dynamic, since different environmental combinations impacted the representativeness of the complete network in a different way. This analysis also provides a graphical view of the impact of the environment removal from the network. Once detected points below the established correlation, the researcher could infer about the network minimum environment number and, suggest through consistent information of several testing years, the environment exclusion.

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ABSTRACT. The conservation of okra landraces [Abelmoschus esculentus (L.) Moench] in gene banks is essential for the success of their use in breeding programmes. This study evaluated the genetic diversity among okra landraces in Brazil based on morphoagronomic descriptors and AFLP markers. We studied 30 accessions of the vegetable gene bank of the Universidade Federal de Viçosa. To this end, 17 morphoagronomic descriptors and five combinations of AFLP primers were used. Genetic parameters were estimated for the quantitative traits and the accessions were grouped by Ward’s method, using the Gower’s and Jaccard’s distance measures, respectively, for the morphoagronomic and molecular data. Polymorphisms were observed for all qualitative traits, while the quantitative traits were significant by deviance analysis. The genetic parameters confirmed the existence of variability among accessions, and high accuracy and heritability indices were found for the traits related to fruit and plant height. Ward’s grouping showed no relationship between the clusters formed with the morphoagronomic and molecular data and the geographical origin of the accessions. No association between morphoagronomic descriptors and AFLP markers was observed. The lack of correlation suggests that both approaches of characterization are important to understand and differentiate the okra accessions.

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ABSTRACT. The genetic differentiation of grapevine rootstock varieties was inferred by the Artificial Neural Network approach based on the Self-Organizing Map algorithm. A combination of RAPD and SSR molecular markers, yielding polymorphic informative loci, was used to determine the genetic characterization among the rootstock varieties 420-A, Schwarzmann, IAC-766 Campinas, Traviú, Kober 5BB, and IAC-572 Jales. A neural network algorithm, based on allelic frequency, showed that the individual grapevine rootstocks (n = 64) were grouped into three genetically differentiated clusters. Cluster 1 included only the Kober 5BB rootstock, Cluster 2 included rootstocks of the varieties Traviú and IAC-572, and Cluster 3 included 420-A, Schwarzmann and IAC-766 plants. Evidence from the current study indicates that, despite the morphological similarities of the 420-A and Kober 5BB varieties, which share the same genetic origin, two new varieties were generated that are genetically divergent and show differences in performance.

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ABSTRACT. The objective of this study was to evaluate gene expression related to water deficit tolerance in maize lines. For this, lines previously classified as tolerant (91-T and 32-T) and non-tolerant (24-NT and 57-NT) to water deficit were used. The seeds of the four lines were evaluated for emergence and emergence speed index, and the seedlings were evaluated for root and shoot length under two conditions of water availability (70 and 10% substrate water retention capacity). In transcript analysis, the expression of several genes associated with water deficit tolerance, ZmDBP3, ZmALDH9, ZmAN13, and ZmDREB2A, was evaluated by qRT-PCR for the 91-T and 57-NT lines. It can be concluded that soil water deficiency did not reduce root development. However, the shoot length was significantly lower under dry conditions. Through transcript analysis, the genes ZmDBP3 and ZmAN13 were identified as potential markers for the early selection of maize lines tolerant to water deficit.

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ABSTRACT. The breeding program of Urochloa ruziziensis evaluates many genotypes in initial phases. Evaluations through grades might make the selection less costly. The aim of this study was to verify the efficiency of visual selection for green biomass yield in relation to different selection strategies, such as mass selection by phenotypic mean, BLUP (Best Linear Unbiased Prediction) and at random. For this purpose, 2,309 regular genotypes were evaluated in an augmented block design in two cuts. The evaluators gave grades for plant vigor, and later, the plots were measured for green biomass yield. The coincidences of the selected genotypes were estimated by different selection strategies. Then, 254 clones of the genotypes selected in different strategies were evaluated in a clonal test in a triple lattice design in four cuts. The statistical analyses were performed in SAS using the Mixed procedure. The regular genotype level and clone-mean basis heritabilities were 31.16 and 62.91%, respectively, for green mass yield. The expected selection gains were 21.09% (visual), 25.43% (phenotypic mean), and 27.5% (BLUP). Moreover, the realized heritabilities for these strategies were 15.58, 11.87, and 15.86%, respectively, which might be associated with genotype by environment interaction. Therefore, the visual selection could be a useful strategy in initial phases of a U. ruziziensis breeding program because the efficiency was moderate to high in relation to phenotypic mean and BLUP.

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ABSTRACT. The palm tree juçara (Euterpe edulis Mart) is considered one of the most important and threatened native species in the Atlantic Forest. The search for juçara seeds (Euterpe edulis Martius) has increased, generating a need for technologies favorable to their production, quality and conservation. The aim of this study was to describe the seed germination patterns of 45 juçara accessions by using a nonlinear model to examine the behavior of these patterns and select superior genotypes. After clustering 45 juçara accessions into four groups, four nonlinear models, namely, the logistic, Gompertz, von Bertalanffy and Weibull models, were tested based on their fit for each group of accessions. The Gompertz model presented the best fit to describe the germination growth curve of E. edulis seeds. Groups 3 and 4 presented the highest daily germination rates and were considered the most vigorous. Analysis of deviance was performed, revealing genetic variability among the genotypes in terms of seed germination and vigor. It was possible to find a nonlinear model that best explained our data, and this model may also be a promising model for other palm tree species. It is possible to select genotypes based on the characters we analyzed, due to the elevated genetic variability.

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ABSTRACT. The objective of this study was to compare different graphical dispersion analysis techniques in two- or three-dimensional planes. In this study, the data from different published works were used in order to determine the best methodology for analyzing the genetic diversity of different species. In this study, efficiency is measured by the amount of original distance absorbed by the projection of distances technique, which in the case of major components is equal to the amount of total variation originally available and retained by the principal components used for dispersion purposes. The projection of dissimilarity measurement technique, principal component analysis (PCA), and principal coordinate analysis (PCoA) were used. Considering the analysis by means of three orthogonal axes, the graphical dispersion efficiency was 82.22 for PCA, 87.22 for PCoA, and 85.25 for the projection of distances technique. For the 2D analysis, considering the two main axes, the mean dispersion efficiency was 69.90 for the PCA, 75.06 for the projection technique, and 78.16 for PCoA. Considering the studies carried out with experimental data of six different species, it is concluded that the principal coordinate analysis is superior.

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ABSTRACT. The aim of this work was to verify by means of adaptability and stability analyses which genotype of Plinia sp. (jabuticaba tree) is more adapted to orchard conditions, based on the measures of stem growth and primary shoots. During a three-year period, the initial growth of jabuticaba tree genotypes from the native fruit collection of the Experimental Station of the Universidade Tecnológica Federal do Paraná - Câmpus Dois Vizinhos was evaluated. These genotypes included seedlings from forest fragments of the southwestern region of Paraná State and some from Minas Gerais State, Brazil. Analysis of variance (ANOVA) was performed, in a 29 x 3 factorial design, with three replicates in each treatment. Phenotypic adaptability and genotypic stability were evaluated based on the data obtained by the following methods: Eberhart and Russell, Lin and Binns and the AMMI. The analyses were carried out through the computer programs GENES and Stability. The methods that were tested to determine the adaptability and stability of the growth behaviour of the jabuticaba tree did not present consistent patterns in the results. However, the genotype generally referred to as 'Vitorino' was the most suitable for open-air cultivation.

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ABSTRACT. Tissue culture techniques have been employed for bromeliad mass propagation by means of the morphogenetic route of nodular cluster cultures (NCs). This study aimed to assess protein, carbohydrate and global DNA methylation (GDM) level dynamics during NCs induction from Vriesea reitzii seeds. Seeds were inoculated into Murashige and Skoog (MS) liquid medium supplemented with 4 µM α-naphthaleneacetic acid (NAA) to induce NCs and in culture medium without plant growth regulators to form normal seedlings. Samples collected at 0, 3, 7, 10, 14, and 21 days of culture were analyzed. All parameters assessed showed the same variation pattern. However, seeds inducing NCs showed significantly lower starch (6.0 mg g-1 FM), carbohydrate (10.7 mg g-1 FM) and GDM (11.0%) levels than seeds forming normal seedlings after 21 days in culture. On the other hand, the protein content (9.1 mg g-1 FM) was significantly higher during induction. NCs induction process through seeds is the result of gene reprogramming in the explant, which leads to morphological, biochemical and metabolic alterations. This involves dedifferentiation, high cell proliferation, high energy demand and protein synthesis, which is related to elevated metabolic activity.

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ABSTRACT. Crambe is an oilseed plant producing oil that can be used for various industrial purposes, including the production of biofuel. It is a short-cycle, non-food plant that can be grown as a second crop following soybean or corn crops and using the same agricultural machinery. This work aimed to estimate genetic parameters and correlations between traits of genotypes grown for two years in seven locations in two Brazilian states. The cultivar FMS Brilhante and the lines CR 1101, CR 1102, CR 1105, CR 1202, CR 1303, and CR 1304 were used. The traits evaluated were grain yield (YD), plant height (PH), stem diameter (SD), first fruiting branch height (BH), 1,000-seed weight (SW), and number of branches (NB). The correlations between traits were identified from the phenotypic covariance matrix through path analysis. Based on the joint analysis, the interaction of genotypes x years x locations was observed. Expressive genetic variability was verified for all evaluated traits, which allows gains to be made with the selection of genotypes. High broad-sense heritabilities based on plot means were verified for YD, BH, and SW (82, 84 and 77%, respectively), which indicates the possibility of directly selecting them. SW and SD showed the greatest direct effects and strongest correlations with YD.

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ABSTRACT. White mold caused by Sclerotinia sclerotiorum (Lib.) de Bary is a devastating disease that affects the common bean (Phaseolus vulgaris. L) crop worldwide. In Argentina, white mold has been detected in all bean production areas, reaching seed yield and quality losses up to 100% on susceptible common bean cultivars under favorable weather conditions. The aim of this study was to screen the physiological resistance of 20 common bean accessions to five genetically distinct isolates of S. sclerotiorum collected from the main common bean growing area of Argentina, using the greenhouse straw test. The white mold reaction was scored at 7, 14, and 21 days post-inoculation using a 1 (no disease symptoms) to 9 (severely diseased or dead plants) scale and the area under the disease progress curve (AUDPC) was determined. Highly significant differences (p < 0.001) were observed between isolates, accessions and genotype x isolate interaction at the three evaluations dates. All cultivars and lines were susceptible at the end of the assessment, except line A 195 which was resistant to white mold against the five isolates tested and was significantly different from all accessions. This work represents a valuable contribution to regional breeding programmes aimed to obtain cultivars with durable resistance.

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ABSTRACT. The success of sugarcane (Saccharum spp.) breeding programs depends on the choice of productive parent lines that have a high industrial yield and are genetically divergent. This study assessed the genetic divergence and population structure of sugarcane accessions that are the parents of the RB05 Series of the Sugarcane Breeding Program of Brazil. The DNA of 82 accessions was evaluated using 36 simple sequence repeat markers. The Jaccard similarity coefficient and Unweighted Pair Group Method with Arithmetic Mean clustering method were used to generate a cluster that was divided into 17 distinct groups derived from probabilistic models. The similarity coefficient used in both cases showed that the degree of similarity varied from 0.4716 (RB971551 x RB965586) to 0.9526 (RB936001 x SP89-1115), with a mean of 0.8536. This result demonstrates a high similarity between the 82 accessions and confirms Wright’s F statistic (0.125), which indicates moderate genetic variability. The less-similar crosses suggest that breeders seek a higher number of crosses using cultivar RB965586, highlighting the RB971551 x RB965586 and RB965586 x RB855511 crosses. The results demonstrate that crosses such as RB936001 x SP89-1115 and RB945954 x RB896342 should be avoided because of their high genetic similarity.

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ABSTRACT. Trait selection is occasionally necessary to save money and time, as well as accelerate breeding program processes. This study aimed to propose two criteria to select traits based on a Procrustes analysis that are poorly explored in genetic breeding: Criterion 1 (backward algorithm) and Criterion 2 (exhaustive algorithm). Then, these two criteria were further compared with Jolliffe’s criterion, which has often been used to select traits in genetic diversity studies. Sixteen agronomic traits were considered, and 40 Conilon coffee (Coffea canephora) accessions were evaluated. This study showed that the flexibility in selecting traits by researcher preference, graphical visualization, and Procrustes M2 tatistic through criteria 1 and 2 is a fast and reliable alternative for decision-making. These decisions are based on the removal and addition of traits for phenotyping in studies of Conilon coffee diversity that can be applied to other crops. Other relevant aspects of selection traits criteria were also discussed.

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ABSTRACT. The objective of this study was to estimate the coefficient of repeatability and the number of measurements required for production and quality variables in a strawberry crop. An experiment was conducted with two strawberry cultivars from two origins grown in four substrate mixtures, totaling 16 treatments, evaluated in a randomized block design with four replications. Mass (MF) and number (NF) of fruits per plant were evaluated as measures of production, and total soluble solids (SST), titratable acidity (AT) and firmness (FIR) of fruits during the crop cycle were evaluated as measures of quality. Subsequently, the repeatability coefficient was estimated by the following methods: analysis of variance (ANOVA), principal component analysis using a correlation matrix (PCcor), principal component analysis using a variance-covariance matrix (PCcov) and structural analysis (SA). The number of measurements was adjusted for each studied variable based on determination coefficients of 0.80, 0.85, 0.90, and 0.95. The repeatability coefficients ranged from low to medium. The ANOVA method gave the lowest r values, while the PCcov method presented the highest values of r. When using the PCcov method, 3.6, 2.9, 6.2, 3.2, and 3.8 measurements were needed to reach 80% confidence for the variables MF, NF, SST, AT, and FIR, respectively, and this increased to 7.3, 14.0, 29.6, 15.4, and 18.1 for 95% confidence in the results for MF, NF, SST, AT, and FIR, respectively.

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ABSTRACT. This study aimed to present the advancements in different breeding stages of super sweet corn (SS), from heterotic field corn populations to the single-cross of SS. Two parental field corn populations, four backcrossed SS populations, four SS intervarietal hybrids (SS-IH), eighteen SS single hybrids (SS-SCH) and two controls were evaluated in two environments over two crop years. The SS-IH and SS-SCH categories presented the highest ear yield, and SS-SCH presented the highest ear yield without husk (11.3 t ha-1). Although SS-SCH was the most productive category, it presented the lowest husk coverage quality. The ear yield and husk cover traits expressed the highest heterosis based on the midparents. The hybrid genotype categories (SS-SCH, SS-IH and controls) had the greatest ear length and diameter, as well as plant and ear height. It was possible to conclude that the techniques used to exploit heterosis are efficient in increasing SS yield but not husk coverage, since this trait requires productive parents. Single-crosses, such as LCSH-116 x LP8HS-129 and LCSH-116 x LP8HS-130, stood out as promising genotypes for registration since they recorded high husk coverage yield and quality.

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ABSTRACT. The aim of this study was to perform a morphological and morphoagronomic analysis of wild Manihot species from a Brazilian semiarid region for inclusion in the collection at the Center for Agricultural Sciences, Federal University of Paraíba. To characterize the 55 accessions, 12 quantitative and 18 qualitative descriptors were used. A dissimilarity matrix was generated by Mahalanobis generalized distance (D²), and clusters were identified by the UPGMA method. It was possible to verify the formation of 8 dissimilar groups based on morphological characters and 5 groups based on morphometric characters, indicating the presence of genetic diversity among accessions. The evaluated morphometric variable with the greatest relative contribution was the length between the central lobe. Based on the dissimilarity matrix, the accessions 16 x 48 were the most genetically distant accessions, followed by 47 x 49. The accessions 4 Monteiro, 16 Soledad, 38 Boa Vista, 3 Pedra Lavrada, 7 Junco, 10 Barra de Santa Rosa, 21 Monteiro, and 39 Junco are the most promising and can be used as parents in breeding programs for this forage species.

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ABSTRACT. The present study aimed to select efficient arbuscular mycorrhizal fungi (AMF) for sugarcane growth and P nutrition in four soils that spontaneously contained dark septate endophytes (DSE). The effect of nine AMF isolates was evaluated individually in sugarcane presprouted seedlings (SP81-3250) grown under greenhouse conditions for a 120-day period. The isolates that stimulated plant growth in the soils with low P availability were Acaulospora colombiana (ACOL), Claroideoglomus etunicatum (CETU), Gigaspora margarita (GMAR), Rhizophagus clarus (RCLA) and Scutellospora calospora (SCAL). Compared to the Yellow Argisol, which had the highest P level, the Red-Yellow Argisol, with an intermediate P content, increased plant height. Compared to the other treatments, inoculation with ACOL, RCLA, and SCAL resulted in higher foliar P content in plants grown in soils with high to intermediate P levels. Root colonization by AMF and DSE was verified in the plants, with the coexistence of both fungal groups in the same plant and/or root fragment. However, AMF colonization was low compared to DSE colonization. The cooccurrence of DSE and AMF was higher in the plants inoculated with ACOL, RCLA, SCAL, and Dentiscutata heterogama. ACOL, CETU, GMAR, RCLA, and SCAL are AMF isolates that have the potential to establish a mycorrhizal inoculant for sugarcane that would be effective in several soils.

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ABSTRACT. Agar media with insoluble phosphates are used for semi-quantitative screening of phosphate-solubilizing bacteria based on the solubilization halo formed around the colonies. We show that the volume of the culture medium (15, 20, and 30 mL) and the inoculation method (toothpick vs microdrop) strongly influence the diameter of the solubilization halo, and this should be considered in advance selection of the isolates most efficient in this process.

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ABSTRACT. The use of plant growth-promoting bacteria (PGPB), which aims to replace chemical fertilizers and biological control, is a goal for achieving agriculture sustainability. In this scenario, our goal was to identify and evaluate the potential of bacteria isolated from maize roots to promote plant growth and be used as inoculants. We evaluated 173 bacterial strains isolated from the maize (Zea mays L.) rhizosphere for the properties of their PGPB in vitro. Twelve strains were positive for siderophores, indole acetic acid (IAA) production, biological nitrogen fixation (BNF), and phosphate solubilization. Sequence analysis of 16S rRNA identified these strains as belonging to the genera Cellulosimicrobium, Stenotrophomonas, Enterobacter, and Bacillus. The elite strains were evaluated under greenhouse conditions upon the inoculation of two maize hybrids, ATL100 and KWX628. The ability of the isolates to promote plant growth was dependent on the maize genotype; Enterobacter sp. LGMB208 showed the best ability to promote growth of hybrid ATL100, while Enterobacter sp. strains LGMB125, LGMB225, and LGMB274 and Cellulosimicrobium sp. strain LGMB239 showed the best ability to promote growth of hybrid KWX628. The results highlight the potential of bacterial genera little explored as maize PGPB but indicate the need to investigate their interactions with different plant genotypes.

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ABSTRACT. The objective of this study is to analyze the growth of wild species of tomato, of the cultivar Redenção and of the respective F1 hybrids of interspecific crossings. We evaluated six wild-type accessions (Solanum pimpinellifolium ‘AF 26970’, S. galapagense ‘LA-1401’, S. peruvianum ‘AF 19684’, S. habrochaites var. hirsutum ‘PI-127826’, S. habrochaites var. glabratum ‘PI-134417’, and S. pennellii ‘LA-716’) and the commercial cultivar Redenção (S. lycopersicum) together with their respective interspecific hybrids. In completely randomized blocks and plots subdivided by time (16, 28, 42, 56, 70, and 84 days after transplanting), we evaluated leaf area (LA), total dry matter (TDM), absolute growth rate (AGR), relative growth rate (RGR) and net assimilation rate (NAR). The distribution of assimilates in the different organs followed different patterns according to genotype. There was a greater accumulation of LA and TDM in the accessions ‘PI-127826’ and ‘PI-134417’ and in the hybrids ‘Redenção’ x ‘PI-127826’ and ‘Redenção’ x ‘PI-134417’. Due to a heterotrophic effect provided by the crossings, there were higher LA, TDM, AGR, RGR and NAR in hybrids than in parent plants. The accessions ‘PI-127826’ and ‘PI-134417’ presented a potential to be donor parents for obtaining tomatoes with a greater capacity of net assimilation and biomass accumulation.

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ABSTRACT. In this work, we report the effects of the harvesting time, the stages in fruit ripening and the influence of potassium nitrate in V. quercifolia seed germination. In addition, information about the storage period and light requirements is provided. Fruits were harvested at the beginning and at the end of the fruiting season, and they were classified into five ripening categories. Seed germination was evaluated with two factorial experiments: 1) harvesting time, fruit ripening, and pre-germination treatment; 2) storage and light requirements. The response variables were germination percentage, mean germination time, and seedling vigor. Seeds harvested at the beginning of the season appeared to be less dormant and they were not influenced by fruit ripening or pre-germination treatments. By contrast, seeds harvested at the end of the season were influenced by fruit ripening and pre-germination treatments. Light and seed storage had a positive effect on germination. Mean germination time varied from 12 to 40 days, and vigor index was positively influenced by potassium nitrate. V.quercifolia seeds are photoblastic positive at constant temperatures and their dormancy can be influenced by harvest time, fruit ripening and a storage period.

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ABSTRACT. The increased demand for potato by the Brazilian processing industry requires long term refrigerated storage, but after a few months, natural dormancy ends, and sprouts start to grow. Thus, sprout inhibitors are necessary to reduce the rate of growth and allow further storage. The purpose of research described here was to determine the effects clove and menthol essential oils have on the inhibition of sprout growth in non-dormant ‘Asterix’ tubers. Both eugenol and menthol treatments reduced the rate of sprout growth during storage at 8oC for up to 50 days. Eugenol and menthol essential oils diminished the rate of accumulation of reducing sugar, which are responsible for browning of French fries. Color after frying was within acceptable levels when the tubers were treated with eugenol or menthol essential oils.

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ABSTRACT. Macauba fruits are oil-rich drupes with high moisture content at harvest. This feature can affect the chemical properties of the oil and increase the costs of biodiesel production. Therefore, it is necessary to adopt postharvest strategies to ensure oil quality. The aim of this work was to evaluate the effect of drying macauba fruit on the quality of the pulp oil. Husked and dehusked fruits were dried at 60°C and then stored. At 0, 15, 45, 100, and 180 days after storage, fruit samples were retrieved, and the oil from the pulp was evaluated for physicochemical parameters. The removal of the husk from the fruits considerably reduced the drying time compared to that of the husked fruits. Drying prevented deterioration of the fruit even after 180 days of storage, regardless of the presence of the husk. The drying process allowed for efficient storage of the macauba fruit while maintaining low levels of oil acidity. Furthermore, the oxidative stability of the pulp oil from the dehusked dried fruits lasted longer than that from the husked dried fruits. Therefore, drying is a viable alternative for the postharvest of macauba fruits to maintain the quality of the oil for biodiesel production.

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ABSTRACT. Environment and storage time influence stored seed quality, especially for oilseeds such as castor beans because they have a high lipid content and are more prone to deterioration. This study evaluated the physiological quality of seeds from three castor bean genotypes stored at 10 and 20°C for 300 days. The experimental design was completely randomized, with 4 replications, in a 2 x 6 (2 temperatures x 6 storage periods) split-plot design. The seeds were placed in low-density polypropylene bags and stored in climatic chambers at 10 and 20°C, in which the temperature and relative humidity were registered. Physiological quality (germination, germination rate index, emergence, rate of emergence, electrical conductivity and accelerated aging) were evaluated at baseline and after 60, 120, 180, 240, and 300 days of storage. Castor seeds of genotype EVF 106 showed better physiological quality when stored at 10°C. Castor seeds of genotype EVF 701 could be stored at 10 and 20°C for 300 days. Castor seeds of genotype EVF 712 presented reduced physiological quality during their 300 days in storage, regardless of temperature.

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ABSTRACT. Beans can be found in different grain colours, and for this reason, it is important to understand the technological and nutritional quality of the diverse types of beans that are consumed. The objectives of this work were to identify the traits that determine Brazilian consumer choice of different bean colours and to evaluate whether different bean colours present differences in technological and nutritional traits. For this purpose, beans of different colours (white, cranberry, matte red kidney, shiny red kidney, and black) were obtained from supermarkets. The samples were evaluated for consumer preference and the technological and nutritional traits of the beans. In southern Brazil, the majority of the survey participants (58%) preferred black beans, and their choice was based on consumption habit (66%) and grain colour (30%). Different bean colours presented differences for all traits related to technological and nutritional quality, except for potassium concentration. Consumption habit and grain colour defined consumer choice for black beans. Black beans were preferred by 58% of the participants, and this type of bean has high concentrations of calcium, magnesium, iron, zinc and copper.

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ABSTRACT. This study aimed to evaluate the dynamics, population density of tillers and stability index of Urochloa brizantha in silvopastoral systems composed of babassu palm trees in the Pre-Amazon region. Four systems consisting of different densities of palm trees (80, 131, and 160 palms ha-1) and a monocrop were evaluated. The rates at which the basal tillers appeared in systems with 131 and 160 palms ha-1 were similar to each other and were slower compared to the monocrop pasture and the system with 80 palms ha-1. Despite the variations, the stability index was always higher than 1.0, which infers a compensatory mechanism between tiller appearance and mortality rate, since monocrop pastures and systems with 80 palms ha-1 have a higher rate of tissue turnover with high rates of tiller appearance and mortality; in contrast, the system with 160 palms ha-1 presents high tiller survival rates. Both the 160 and 131 palms ha-1 systems indicate impaired canopy renewal, as seen in the low appearance rate of basal tillers due to shading. As such, the tillering dynamics of the systems vary according to the density of palm trees, and the smaller tree densities favor the tiller turnover in the first generations evaluated.

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ABSTRACT. Calcium chloride application on fruits maintains the firmness of fruits, decreases storage breakdown and rot, extends shelf-life, and increases vitamin C and calcium content. Blackberries have low post-harvest durability due to the intrinsic characteristics of their fruits, mainly the high respiratory rate and low firmness, which causes problems in the production chain of fresh fruits. The current study aimed to evaluate the effects of pre-harvest application of calcium chloride on the fruits of ‘Tupy’ blackberry (Rubus spp.). A randomized block design for a factorial scheme was used, i.e. calcium chloride concentrations (0, 1.5, 3, and 4.5%) and number of applications (1, 2, and 3). Multiple applications occurred between 5-day intervals. The results showed that the calcium content in the fruits increased with a single application of 2.2%, but a decrease in mass loss was observed with a 4.5% application. The results also indicated great firmness and ascorbic acid content of fruits of ‘Tupy’ blackberry, in addition to the significant increase in fruit size and mass. However, in general, the content of soluble solids, sugars, antioxidant activity and total polyphenols decreased.

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ABSTRACT. Because of climatic changes, the cultivation of temperate climate plants such as peach in subtropical climates has become a challenge. In these areas, temperatures exceeding 25°C often occur during the pre-flowering and flowering phases. The high temperature causes damages by acting during the early stages of pollen-pistil interaction processes. The objective of this work was to evaluate the stigmatic receptivity of peach flowers at 18°C and 30°C. The pollen adherence was evaluated as well as the germination and presence of pollen tubes in the transmitting tissue of the style. The genotypes responded differently to temperature. ‘Granada,’ ‘Diamante’, and ‘Sensação’ had a stigmatic receptivity that was less affected when flowers were exposed to the higher temperature. Most genotypes showed a reduction in the number of pistils with pollen tubes growing in the style, particularly when pollination was delayed.

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ABSTRACT. The objective of this work was to determine the adequate nitrogen (N) dose via fertigation associated with the maximum economic production of maize for silage, in two agricultural crops (summer and winter), in the municipality of Canindé de São Francisco-SE, Brazil. The experimental design was in randomized blocks, with four replicates. The treatments consisted of four doses of N (0, 80, 160, and 240 kg ha-1) using urea. The cultivar planted was the hybrid Bt Feroz. The evaluated characteristics were as follows: shoot fresh and dry mass productivity, gross and net incomes, the rate of return and net profit margin. There was an interaction between N doses and agricultural crops for all variables. Higher agroeconomic efficiency in the production of maize for silage was obtained from the winter harvest. In the summer crop, the rate of return (1.82) and the net profit margin (45.52%) were highest when the plants were fertigated with 56.04 and 58.92 kg ha-1 of N, respectively. In winter, the yields of fresh mass, gross and net incomes increased linearly with increasing doses of N, with a profit proportional to the invested capital since nitrogen fertigation did not influence the rate of return (2.24) and the net profit margin (55.22%).

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ABSTRACT. The present research seeks to elucidate the feasibility of chitosan (CHT) in the induction of water deficit tolerance in different maize hybrids, contrasting tolerance to water restriction, tolerance and sensitivity. The maize plants were subjected to water deficit and foliar application of different chitosan doses (60, 100, 140, and 180 mg L-1) at the pre-flowering growth stage and evaluated during the stress period of fifteen days. To understand the induction behaviour of the tolerance to water restriction, biophysical parameters, such as water potential, relative water content and chlorophyll content, gas exchange, and biochemical assays, were quantified based on the activity of SOD, CAT, APX, and PAL antioxidant enzymes, lipid peroxidation activity and hydrogen peroxide content. Among the treatments, maize plants subjected to chitosan foliar application at a dose of 140 mg L-1 presented similar behavioural responses to plants under favourable irrigation conditions. Such positive responses are related to the high degree of activity of antioxidant enzymes, gas exchange and low levels of lipid peroxidation and hydrogen peroxide. The results support the potential use of CHT to increase tolerance to water stress.

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ABSTRACT. The objective of this work was to evaluate the alterations of antioxidant enzyme reserves and antioxidant enzymes during germination under water deficit in maize hybrids and to associate with seed vigor, determining the mechanisms related to tolerance for this stress. Two three-way maize hybrids were characterized by their vigor at different levels of water deficit induced by polyethylene glycol 6000. Next, the seeds were hydrated at different osmotic potentials (0.0, -0.3, and -0.9 MPa) and removed at different times to assess the levels of the total soluble protein, total soluble sugars, proline, starch, and antioxidant enzymes, such as superoxide dismutase, catalase and ascorbate peroxidase. The analysis of variance, Tukey test at 5% and principal component analysis (PCA) were used. The vigorous hybrid (HT1) was more efficient than the low vigor hybrid seeds (HT2) in mobilizing the total soluble protein during the initial stages of germination and the total soluble sugars before and after root protrusion under water deficit in addition to increasing the catalase activity at the different osmotic potentials that were assessed.

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ABSTRACT. The objectives of this study were to evaluate the effect of the chemical composition of soybean seeds and the efficiency of seed mineral supplementation on physiological quality and field performance. Two seed lots (high and low levels of mineral nutrition), with or without supplemental macro- and micronutrients, of three soybean cultivars (BMX Potência RR, BMX Turbo RR, and BMX Magna RR) were used. For the laboratory experiment, a completely randomized design with four replications was used. To evaluate the physiological quality of the seeds, the water content, first count, germination, 1,000-seed weight, and length and dry weight of the seedling were determined. For the field experiment, a randomized block design with four replications was used, and seedling emergence and grain yield were evaluated. Seeds with higher nutrient content produced seedlings of greater vigor and higher grain yield for all of the cultivars studied. The use of mineral supplementation in seed lots with low nutrient content resulted in greater vigor under laboratory conditions. The increase in grain yield after mineral supplementation depends on the quality of the seed lot.

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ABSTRACT. Calcium (Ca2+) is a nutrient in tomato plants, of which deficiency usually causes several problems including a physiological disorder known as blossom-end rot (BER) in the fruit. The objective of this study was to evaluate and identify morphological and physiological characteristics related to the susceptibility of tomato varieties to BER. The varieties studied were ‘Amalia’, ‘IPA-6’, ‘M-82’, ‘Mara’, and ‘Nagcarlan’, presenting different fruit formats. Physiological parameters that negatively correlated with BER were plant water potential, leaf area, plant dry mass, relationship between proximal/distal Ca2+, K+ content in the proximal and distal portions of the fruit, and proximal Ca2+ content. Physiological parameters that positively correlated with BER were number of trichomes in the abaxial and adaxial leaf portions, leaf stomatal conductance, distal Ca2+ content bound to the cell wall, leaf transpiration, and fruit length. Our results showed that ‘Mara’ and ‘Nagcarlan’, ‘Amalia’ and ‘IPA-6’, and ‘M-82’ presented low, medium, and high susceptibility to BER, respectively. We also found that total fruit Ca2+ concentration, particularly in the distal fruit tissue, was not the only factor responsible for the development of BER; rather, the balance between factors that increase and decrease the susceptibility of each variety affected development of this disorder.

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ABSTRACT. The effects of the dose and application method of limestone - broadcast or in furrow - and of agricultural gypsum on soil fertility, the control of clubroot, and cauliflower development in mountain farming areas were evaluated. Initially, four doses of broadcast limestone (0.0, 1.0, 2.0, and 4.0 Mg ha-1) and two cauliflower cultivars (Sharon and Piracicaba Precoce) were analyzed. A second experiment evaluated limestone (4.0 Mg ha-1) application treatments: broadcast and in furrow, broadcast limestone + gypsum (3.0 + 1.0 Mg ha-1), and broadcast gypsum (1.0 Mg ha-1). Soil fertility was improved, and significant increases were observed in the total and healthy root volume with increasing doses of limestone. With 4.0 Mg ha-1, a 58 and 85% increase in yield was observed in Sharon and Piracicaba, respectively, compared to the control. Treatments with limestone and limestone + gypsum, regardless of the application method, elevated pH (≥ 10%), base saturation (V%) (≥ 37%), and calcium (Ca) contents (≥ 100%), and reduced the levels of aluminum ions (Al3+) (≥ 60%) and clubroot severity (≥ 64%) and favored biomass accumulation (≥ 27%) and yield (≥ 9.2%). The application of limestone in the furrow yielded results similar to the broadcast application.

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ABSTRACT. The objective of this study was to evaluate the activity of invertases and amylases in Brachiaria brizantha cv. Marandu under various shade and nitrogen fertilization conditions. The experiment was carried out in a greenhouse using a 4 x 2 factorial scheme (shading levels of 0, 30, 50, and 80% and fertilization with 0 and 100 kg N ha-1). The activity of the enzymes, cytosol-neutral invertase (Inv-N), vacuole acid (Inv-V) and cell-acidic acid (Inv-CW), reducing sugars (RS), and α and β-amylases were evaluated (α = 0.05). The interaction was significant for Inv-N within the leaf. In the first cycle, the highest activity was in fertilized plants with 30, 50, and 80% shading. For Inv-CW in the 1st cycle, the highest activity occurred with 0, 30, and 50% shading. However, the interaction for Inv-V leaf activity was not significant in the 1st and 2nd cycles. The highest activity observed for Inv-V was in the fertilized plants, suggesting that fertilization increased the enzymatic activity. The activity of the invertases increased both under 30-50% shaded conditions and in full sun. Furthermore, invertase activity was directly linked to the osmoregulatory system. The reduction in RS was related to a low photosynthetic rate, and an increase α and β-amylase was associated with the use of reserve energy sources to meet energetic needs.

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ABSTRACT. Bell peppers are sensitive to salinity; therefore, it is necessary to find alternatives to reduce saline stress. An experiment was conducted in a greenhouse at Federal Rural University of the Semi-Arid Region, in Mossoró, Rio Grande do Norte State, Brazil, to evaluate the effects of salinity and K+/Ca2+ ratios on bell pepper production. The experimental design consisted of randomized blocks in a 5 x 4 factorial scheme with four replicates, corresponding to five K+/Ca2+ ratios (F1 = 3.3/1, F2 = 2.8/1, F3 = 2.2/1, F4 = 1.8/1, and F5 = 1.5/1) and four salinity levels in the nutrient solution using NaCl (1.75, 3.25, 4.75, and 6.25 dS m-1). The following parameters were evaluated: the number of fruits (total, marketable and unmarketable), the mean weight of fruits (marketable and unmarketable), fruit production (total, marketable and percentage of marketable fruits) and a salinity tolerance index. Generally, nutrient solution enrichment with K+ or Ca2+ did not cause significant increments in bell pepper yield. The fertigation treatments F2, F3, and F5 led to a higher bell pepper tolerance to salinity, allowing waters with higher salt concentrations to be used without causing a reduction in the yield.

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ABSTRACT. Pearson's correlation and spatial variability are tools that can be used to help one understand the process of losses in the mechanical harvesting of cotton. Therefore, the objective of this study was to model the spatial distribution and map the losses of mechanical cotton harvest using geostatistics and to correlate the losses with agronomic variables using Pearson’s correlation. The experiment was conducted in Itiquira and Lucas do Rio Verde, Mato Grosso State, Brazil. At each sampling point, the evaluated variables were agronomic plant variables and cotton losses in the soil and the plant (divided into lower, medium and upper thirds) and the sum total of losses. The highest losses in cotton harvest occurred in the lower third and on the soil, both of which exhibit a spatial dependence model, according to geostatistics, demonstrating that they do not occur in a randomized process and are related to the specific plant. There was a relationship between the plant populations with losses in the cotton crop. The plant population can influence the spatial dependence of losses.

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ABSTRACT. The present study aims to determine whether exogenous salicylic acid (SA) or spermidine (Spd) has any protective effect against salt stress. Seeds were subjected to 0, 20, 40, and 60 mM NaCl with or without salicylic acid or spermidine (0.5 mM) for 10 days. The evaluated variables were germination rate, shoot and root dry masses, glycine betaine content, lipid peroxidation, and the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). The data were subjected to Tukey’s test (p ≤ 0.05). There was a growth increase, especially in plant shoots. The reduction in lipid peroxidation, as indicated by lower malondialdehyde (MDA) levels, can be explained by an increase in antioxidant activity when SA and Spd were added. When compared to CAT and APX, SOD was the least responsive enzyme to the addition of both SA and Spd in salt-stressed plants. SA and Spd partially reduced the effects of moderate salt stress in both plant species; however, Spd addition had better results than SA in terms of suppressing oxidative stress. Lablab plants were more vigorous than pigeonpea plants.

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ABSTRACT. The objective of this work was to evaluate the response of sunflower cultivars submitted to increasing levels of phosphate fertilization in two crops. The experimental design was a randomized complete block design with four replicates in subdivided plots, where five doses of simple superphosphate (0, 50, 100, 150, and 200 kg ha-1 P2O5) were allocated to the plots and three sunflower cultivars (Aguará 06, Altis 99, and Embrapa 122-V2000) were assigned to the subplots. The variables evaluated were the P content in the diagnostic leaf, number of achenes per capitulum, achene yield (kg ha-1), oil content (%) and oil yield. The phosphorus doses increased the components of production. The dose that provided the best sunflower performance varied for the different cultivars. Among the doses studied, fertilization with 100 kg ha-1 P2O5 in the 2016 agricultural crop and 150 kg ha-1 P2O5 in the 2017 agricultural crop provided the best conditions for sunflower cultivation. The cultivar Aguará 06 produced more achenes and oil than the other cultivars analyzed in the agricultural crops.

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ABSTRACT. Pitaya species cultivation in Brazil is recent, and information on the production of the species Selenicereus megalanthus, known as yellow pitaya, is non-existent because research in the country has focused on the species Hylocereus undatus. The research was carried out with the objective of evaluating the reproductive phenology of the species S. megalanthus, in a high-altitude climate conditions in Brazil. The study orchard of yellow pitaya was located at an altitude of 726 metres, 18º 04' 15" S latitude and 43º 28' 15" W longitude, and has an Aw climate, classified as high-altitude tropical. Phenological evaluations were carried out through visual observations, from the beginning of floral button formation until the end of the fruit harvest, during three production cycles. On each plant, flower buds were marked to determine the time from floral button formation until flower anthesis and from flower fertilisation until fruit ripening. The period of flowering and harvesting of the yellow pitaya was determined according to the phenological stage records. Flowering began in the spring, with successive flowering events until the autumn. The time between floral button formation until anthesis ranged from 46 to 55 days. The time from flower fertilisation until fruit ripening ranged from 96 to 110 days. Fruit harvest began in the summer and ended in winter. The reproductive cycle of S. megalanthus is longer than H. undatus and H. polyrhizus, which are also cultivated in Brazil, ranging from 147 to 166 days from floral button formation to fruit harvest.

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ABSTRACT. This study aimed to evte the quality of Hevea brasiliensis seedlings, a GT1 clone, produced in protected environments in a variety of substrates. The treatments consisted of 13 substrates composed of combinations of cattle manure, soil from a ravine, medium vermiculite, superfine vermiculite and washed fine sand and two environments: a greenhouse with 50% shade using aluminized screen and a plant nursery with 50% shade using a Sombrite® screen. There were no replications of the environments; therefore, each one was considered an experiment. For each environment, a completely randomized experimental design with five replications was used to evaluate the substrates. Subsequently, the average squares of the residuals of individual variance analyses of these treatments (substrates) were evaluated, and because they did not exceed an approximate ratio of 7:1, a combined analysis of experiments was performed with Sisvar software. Two hundred eighty days after sowing, the dry weight, plant height, stem diameter, diameter at five centimeters above soil and the seedling quality indices were evaluated. Results indicated that substrates with a low amount of manure and sand and a high amount of vermiculite (S9 and S13) produced rubber tree seedlings of high-quality. The environment with greater radiation availability was better for the development of high-quality rubber tree seedlings.

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ABSTRACT. Plinia peruviana is a species that is native to Brazil and is important due to the taste and medicinal properties of its fruits. Young leaves and split mature seeds were used as explants to initiate somatic embryogenesis to obtain a large number of plants in a short period of time. Leaf discs were cultured in MS medium containing various concentrations of 2,4-D (2,4-dichlorophenoxyacetic acid) or picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid). In the case of the mature seeds, various concentrations of glutamine, 2,4-D and a combination of auxin and BAP (6-benzylaminopurine) were tested for somatic embryogenesis induction. For somatic embryo maturation, several concentrations of PEG 6000 (polyethylene glycol; up to 90 g L-1) were tested. After 60 days of culture using leaf discs, callus formation occurred in all treatments, with the highest averages obtained with 10 μM 2,4-D. However, these calluses did not form somatic embryos. For the cultured seeds, the best treatment was the MS medium with 1,000 mg L-1 glutamine and 10 μM 2,4-D without BAP. The supplementation of 60 g L-1 PEG 6000 was sufficient to promote the maturation of the somatic embryos. Histological analyses of the calluses that were formed from leaf discs showed nonembryogenic characteristics. In contrast, the calluses that originated from mature seeds had small and round cells with little vacuolation, which are characteristics of embryogenic structures.

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ABSTRACT. This study aimed to evaluate the productive characteristics, gas exchange and water use efficiency of the banana 'Prata-Anã' clone Gorutuba under different irrigation intervals associated with different emitter heights. Therefore, a field experiment was conducted in a 2 x 4 factorial scheme: two irrigation intervals (daily and every two days) and four emitter heights (50, 70, 90, and 110 cm) in a completely randomized design with four replicates. The irrigation depths applied by the microsprinkler irrigation system were calculated as a function of crop evapotranspiration. The gas exchanges were evaluated during the period of greatest climatic stress, and the productive characteristics were evaluated at harvest. The economic water use efficiency was determined indirectly by considering the production divided by the applied irrigation depth, which was the same in all the treatments. The instantaneous water use efficiency was estimated with an infrared gas analyzer in the critical climatic period. There was no interaction between the irrigation intervals and emitter heights. The two-day irrigation interval resulted in lower values of leaf temperature and photosynthetically active radiation incident on the leaves, resulting in a higher fruit weight and, consequently, higher yields and a higher water use efficiency. The highest fruit weights were obtained at heights of 70 and 90 cm.

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ABSTRACT. Filter cake has been one of the most widely used waste products as a source of organic matter in the production of biofertilizers. However, sanitized sewage sludge is a recommended alternative for agricultural use because of environmental issues. Studies that examine the use of this particular class of fertilizer are needed. The objective of this work was to evaluate the efficiency of sewage sludge and filter cake as sources of organic matter in the composition of pelletized biofertilizers for soybean production. The experimental design was a randomized block design in a 2 x 4 + 2 factorial, which includes two sources of organic matter (sanitized sewage sludge and filter cake) and four levels of nitrogen (50, 75, 100, and 125%) relative to the recommended dose of phosphorus pentoxide compared with the mineral fertilizer. The use of organomineral fertilizer with the formulation of 75% sewage sludge showed greater growth for aerial plant parts. Biofertilizers formulated with sewage sludge and filter cake can replace mineral fertilizer and increase soybean growth. Quantitative changes in peroxidase, catalase and urease activity, as well as lipid peroxidation, were observed following the use of biofertilizers.

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ABSTRACT. Selecting genotypes that combine high productivity with high seed quality is a challenge. The exploration of intracultivar genetic variation is an alternative to significantly increase the annual genetic gain and maximize the selection efficiency for both characteristics. The present study aimed to identify intracultivar variation to improve the seed quality of soybean genotypes derived from the commercial cultivar BRS 284, selected using the HSD (Honeycomb Selection Designs) model. Soybean genotypes selected for two years from two environments with contrasting edaphoclimatic characteristics, according to the principles of the HSD selection model, were cultivated under competition by using the experimental model in randomized blocks with four replicates and evaluated regarding the productivity and physiological quality of seeds. The results showed that genotype 284-3 presented a greater mass of 100 seeds, germination, vigour after accelerated ageing test, seedling emergence and emergence speed index than the other genotypes in both environments, with no significant difference in the standard cultivar regarding seed yield. The HSD method was an efficient selection method to identify intracultivar variation to improve cultivar performance.

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ABSTRACT. With the depletion of fossil fuel resources accelerating the search for renewable energy sources, studies on agricultural products containing a significant amount of oil in their compositions have intensified. The objective of this work was to investigate the fatty acid profile and the physiological quality of the oil extracted from niger seeds dried at different temperatures. The seeds were dried at 40, 50, 60, and 70°C, until their moisture content reached 8.5 ± 1% (wet basis). The physiological properties of niger seeds were determined by assessing their germination, germination speed index, mean germination time, cold test, accelerated aging with a saturated solution, emergence percentage, and emergence speed index. The quality of the oil was evaluated using gas chromatography, based on the fatty acid profile. We concluded that drying air temperatures of 40 and 50°C did not compromise the physiological quality of niger seeds. However, the 70°C drying temperature seriously impaired seed quality. The drying temperatures that were used in this study did not substantially alter the fatty acid profile of niger oil.

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ABSTRACT. The creation of proper soil fertility is fundamental to the agroecological transition phase and guarantees the sustainability of organic agribusiness. In a randomized complete block design with a 3 x 2 factorial scheme with 1 additional treatment (control, without organic fertilizer), we tested three poultry litter rates (7, 14, and 21 Mg ha-1) at sowing or splitting between sowing (30%) and side-dressing (70%) for two summer corn whole-plant silage crops and for the soil chemical attributes. The splitting of the poultry litter rate during the rainy season preserves the soil K content, prevents the accumulation of soil P and increases the efficiency of the increasing yields of the organic whole-plant corn silage crop. The reapplication of pre-sowing poultry litter can lead to an accumulation of P and Ca in the soil but favors fresh matter and cob dry matter yields in the dry season. The splitting of the poultry litter rate for whole-plant corn silage can guarantee technical and environmental sustainability in rainy years, but on the other hand, the reapplication of this organic fertilizer only at pre-sowing can increase the fresh matter yield and protein quality of organic whole-plant corn silage cultivated in an Inceptisol in the dry season.

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ABSTRACT. Sustainable production systems, such as the no-tillage system (NTS), have a tendency to increase organic carbon in the soil. However, in Brazilian cotton production, the conventional tillage system (CTS) is predominant, and long-term studies on cotton crop under the NTS are scarce. The present study aimed to evaluate the effect of soil management and crop rotation systems on the cotton fiber yield as well as on the carbon and nitrogen accumulation in the soil. This study was conducted in the Brazilian savanna over 9 years and consisted of the following four treatments with different soil management systems: the NTS and CTS with the succession or rotation of crops (cotton, soybean, maize, and Urochloa ruziziensis). The NTS increased the carbon content by 55% in the top 5 cm after 9 years and increased the carbon stock by approximately 20% at a depth of up to 40 cm. Crop rotation with soybean, maize, and cotton was insufficient to increase the carbon stock in the soil under the CTS. In addition to increasing the fiber yield, the cotton crop in a NTS rotated with soybean + U. ruziziensis and with maize + U. ruziziensis increases the carbon stock and nitrogen content in soil.

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ABSTRACT. Aggregates are the primary structural components of soil and have been used as an indicator of soil quality in conservation systems. The objective of this study was to analyse the effect of slow pre-wetting on the results of the aggregate stability test for different classes of tropical soils. Data were arranged in a 2 x 4 factorial design with three replications, in which the first factor comprised the two methods of pre-treatment on soil aggregates: without pre-wetting (WOPW), which considered the moisture of the aggregates in the field, and with pre-wetting (WPW), which considered the slow wetting of aggregates through capillarity on wet filter paper for 24h. The second factor consisted of four soil classes: Typic Dystrustept (Cambissolo Aplico distrófico in Embrapa), Typic Hapludult (Argissolo Amarelo distrófico), Rhodic Kandiudult (Nitossolo Vermelho distrófico), and Anionic Acrudox (Latossolo Vermelho distróferrico) and considered horizons A and B. The pre-wetting significantly increased the values of the weighted average diameter, geometric mean diameter and aggregate stability index. In soils with high organic carbon content, the practice of pre-moistening did not provide variation in aggregation.

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ABSTRACT. The effect of tillage system (NT-no tillage; CT-conventional tillage; MT-minimum tillage; and NT/scarification, every three years) on soybean nutrient availability and yield was evaluated on Oxisol after 12 years of cultivation. Soil samples were collected at depths of 0.00-0.05, 0.05-0.10, and 0.10-0.20 m and were analyzed for P, K, Ca, Mg, carbon (C), organic matter (OM), pH value, potential CEC, base saturation (BS%), and number of semiquinone organic radicals. The macronutrient concentration in the leaves and amount accumulated in the plants at the blooming stage were determined, as well as the yield of the two soybean crops. The soil pH value, BS% and K, Ca, and Mg concentrations were not influenced by the tillage system. The soil P and OM in the surface layer, however, were inversely proportional to the intensity of soil preparation. The P content in the soil surface layer under NT was twice as high as that of soil under CT. The P content in the soybean leaves under NT was also higher compared to that in the plants under CT and MT. The number of semiquinone radicals was low in the soil surface layer under NT, indicating a small degree of humification. However, soybean yield was not affected by the tillage system.

Resumo em Inglês:

ABSTRACT. In this work, lacunarity analysis is performed on soil pores segmented by the pure voxel extraction method from soil tomography images. The conversion of forest to sugarcane plantation was found to result in higher sugarcane soil pore lacunarity than that of native forest soil, while the porosity was found to be lower. More precisely, this study shows that native forest has more porous soil with a more uniform spatial distribution of pores, while sugarcane soil has lower porosity and a more heterogeneous pore distribution. Moreover, validation through multivariate statistics demonstrates that lacunarity can be considered a relevant index of clustering and can explain the variability among soils under different land use systems. While porosity by itself represents a fundamental concept for quantification of the impact of land use change, the current findings demonstrate that the spatial distribution of pores also plays an important role and that pore lacunarity can be adopted as a complementary tool in studies directed at quantifying the effect of human intervention on soils.