Abstract in English:

ABSTRACT: Brazil is the largest sugarcane producer in the world and the leader in the production of sugar and ethanol. Although sugarcane has become an important factor in the Brazilian economy, cultivation has presented many issues, for example, the problems due to burning before the manual harvest. The Brazilian authorities have approved a law that prohibits this practice and mechanized harvesting has thus become the most fitting approach. Given this development, areas for sugarcane plantation must be properly rebuilt to accommodate the new way of harvesting. The main characteristic demanded of sugarcane plots to use harvesting machines is that they must be rectangular. In the present paper, we propose a methodology for dividing the plantation area into plots and planning their allocation so as to accommodate mechanized harvesting. In view of the requirement for plots to be rectangular, we represented this problem as a two-dimensional cutting problem, and to find a solution we adopted the AND/OR graph approach. The computational experiments were conducted using real cases, and the proposed strategy was shown to perform well.

Abstract in English:

ABSTRACT: Knowing the spatial variability of sugarcane biomass in the early stages of development may help growers in their management decision-making. Proximal canopy sensing is a promising technology that can identify this variability but is limited to quantifying plant-specific parameters. In this study, we evaluated whether biometric variables integrated with canopy reflectance data can assist in the generation of models for early-stage sugarcane biomass prediction. To substantiate this assertion, four sugarcane-producing fields were measured with an active crop canopy sensor and 30 sampling plots were selected for manually quantifying chlorophyll content, plant height, stalk number and aboveground biomass. We determined that Random Forest and Multiple Linear Regression models are similarly able to predict biomass, and that associating biometric variables such as number of stalks and plant height with reflectance data can assist model performance, depending on the attributes selected. This indicates that, when estimating biomass in the early stages, sugarcane growers can carry out site-specific management in order to increase yield and reduce the use of inputs.

Abstract in English:

ABSTRACT: Sugarcane mills in Brazil collect a vast amount of data relating to production on an annual basis. The analysis of this type of database is complex, especially when factors relating to varieties, climate, detailed management techniques, and edaphic conditions are taken into account. The aim of this paper was to perform a decision tree analysis of a detailed database from a production unit and to evaluate the actionable patterns found in terms of their usefulness for increasing production. The decision tree revealed interpretable patterns relating to sugarcane yield (R2 = 0.617), certain of which were actionable and had been previously studied and reported in the literature. Based on two actionable patterns relating to soil chemistry, intervention which will increase production by almost 2 % were suitable for recommendation. The method was successful in reproducing the knowledge of experts of the factors which influence sugarcane yield, and the decision trees can support the decision-making process in the context of production and the formulation of hypotheses for specific experiments.

Abstract in English:

ABSTRACT: Genome-wide selection (GWS) is based on a large number of markers widely distributed throughout the genome. Genome-wide selection provides for the estimation of the effect of each molecular marker on the phenotype, thereby allowing for the capture of all genes affecting the quantitative traits of interest. The main statistical tools applied to GWS are based on random regression or dimensionality reduction methods. In this study a new non-parametric method, called Delta-p was proposed, which was then compared to the Genomic Best Linear Unbiased Predictor (G-BLUP) method. Furthermore, a new selection index combining the genetic values obtained by the G-BLUP and Delta-p, named Delta-p/G-BLUP methods, was proposed. The efficiency of the proposed methods was evaluated through both simulation and real studies. The simulated data consisted of eight scenarios comprising a combination of two levels of heritability, two genetic architectures and two dominance status (absence and complete dominance). Each scenario was simulated ten times. All methods were applied to a real dataset of Asian rice (Oryza sativa) aiming to increase the efficiency of a current breeding program. The methods were compared as regards accuracy of prediction (simulation data) or predictive ability (real dataset), bias and recovery of the true genomic heritability. The results indicated that the proposed Delta-p/G-BLUP index outperformed the other methods in both prediction accuracy and predictive ability.

Abstract in English:

ABSTRACT: An imaginary part model of soil dielectric constant for predicting the soil salinity status was developed based on a series of relations between dielectric imaginary part and soil bulk conductivity, soil bulk conductivity and soil solution electrical conductivity, and soil solution electrical conductivity and ion contents in soil using pot trials with different soil salinity levels in the 2008 growing season. This model was calibrated and tested with data from the 2009 growing season. The results showed that the inverted values of the total concentration of salt (Sc), Cl−, and Ca2+ at low frequencies (P-band of microwave observations) from the imaginary part model fitted well with the observed values, since root mean square errors (RMSEs) were 0.34 g kg−1, 0.09 g kg−1 and 0.13 g kg−1, respectively, but the inversion effect of Na+ was relatively poor. Moreover, the Sc, Cl−, and Na+ could be well inverted at high frequencies (C-band of microwave observations), since RMSEs were minor, with values of 0.25 g kg−1, 0.02 g kg−1, and 0.15 g kg−1, respectively. The close fit between the observed and inverted values indicated that the present models could be used to estimate soil ion content quickly and reliably under different saline conditions, which, when suitable measures are taken, can be used to reduce the effects of soil salinity on crop growth.

Abstract in English:

ABSTRACT: Soybean [Glycine max (L.) Merr.] grain yield is closely associated with the level of optimal nitrogen (N) supply, especially during the reproductive stages. Foliar fertilization with low rates of N have been considered as a strategy for furnishing additional N and enhancing grain yields. Field studies using 15N tracer were conducted over two growing seasons to investigate the impact of foliar N fertilization on grain yield, plant N content, the amount of N derived from fertilizer (NDFF) and N recovery efficiency (NRE). Four foliar N rates (0, 1300, 2600 and 3900 g ha−1) were supplied by two equal split applications at the R1 and R3 stages. Foliar N fertilization of soybean canopies did not affect grain yield, grain N content, shoot N content nor plant N content. Total NDFF was increased from 0.7 to 2.0 kg ha−1 across the N rates. Nonetheless, NRE was unaffected by foliar N fertilization, which averaged 53 %. Soybean plants allocated the same amount of N fertilizer to both grains and shoots. No significant effects of low rate foliar N fertilization were registered on soybean grain yield nor plant N content, despite considerable N fertilizer recovery by plant organs.

Abstract in English:

ABSTRACT: This research investigated the potential of beef products with acid whey to release bioactive peptides and thereby emphasize their health-promoting potential. Peptide sequences were isolated and identified by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). Firstly, the antihealth properties (toxicity, allergenicity) of the peptides were estimated based on the peptide sequences. Next, their health-promoting potential was demonstrated based on an in silico analysis by determining their bioactivity scores (PeptideRanker). Their various biological actions were also determined using BIOPEP-UWM tools. We presented peptide sequences with properties relevant to ensuring good health and well-being, including cardiovascular system, nervous and immune systems, or their support for the maintenance of general homeostasis. We obtained information on generation of biologically active peptides in uncured beef with acid whey and it can be considered as a new knowledge as it contributes to science development of functional and nutraceutical foods. In the long term, this information can be used in designing products with desired nutritional and health-promoting properties that are important for the well-being and for preventing the occurrence of noncommunicable diseases.

Abstract in English:

ABSTRACT: Despite important biotic stresses to common bean, Anthracnose (ANT) and Angular Leaf Spot (ALS) can cause losses of up to 80 % and occur in more than 60 countries around the world. Genetic resistance is the most sustainable strategy to manage these diseases. Thus, we aimed to (1) identify new SNP markers associated with ALS and ANT resistance loci in elite common bean lines, and (2) provide a functional characterization of the DNA sequences containing the identified SNP markers. We evaluated 60 inbred lines, under field conditions, which represent the elite germplasm developed by the Embrapa common bean breeding program across 22 years, in terms of severity of the ALS and ANT. The lines were genotyped with 5,398 SNPs. Then, a Mixed Linear Model was run to determine the SNP-trait associations. We observed two-significant marker-trait associations reacting to ANT, both located on chromosome Pv-02. These markers explained 25 % of the phenotypic variation. For ALS, only one significant marker-trait association was observed, which is located in chromosome Pv-10 and explained 19 % of the phenotypic variation. These markers, along with others already used, will be useful to add or keep ANT and ALS resistance loci identified in this work in the new carioca and black seeded cultivars.

Abstract in English:

ABSTRACT: Genetic redundancy in cassava (Manihot esculenta Crantz) presents a challenge to efficient management of genetic resources. This study aimed to identify and define the genetic structure of duplicates in cassava germplasm from various Embrapa research units, using single-nucleotide polymorphism (SNP) markers. We evaluated 2,371 accessions with 20,712 SNPs. The identification of duplicates was performed based on multilocus genotypes (MLG), adopting a maximum genetic distance threshold of 0.05. The population structure was defined based on discriminant analysis of principal components (DAPC). A total of 1,757 unique and 614 duplicate accessions were identified. The redundancy of the collections ranged from 17 % (Belém, PA – Brazil) to 39 % (Petrolina, PE – Brazil), with an average of 21 %. This redundancy between different research units is probably due to the historical sharing of accessions, as well as collections carried out in the same region, or even to the intense germplasm exchange between farmers with different genotype names. In terms of genetic structure, the 250 principal components explained 88 % of the genetic variation of the SNP markers and defined the hierarchical structure of the duplicate cassava germplasm in 12 groups. Since heterotic groups have not yet been identified for cassava, crosses between accessions of the 12 DAPC groups may be promising. All MLGs were allocated within the same DAPC group, corroborating duplicate analyses yet still revealing high variability between groups that were quite distinct based on the first two discriminant functions. Our results contribute to optimizing the conservation of genetic resources, together with understanding diversity and its use in crop improvement.

Abstract in English:

ABSTRACT: Severe mosaic symptoms, accompanied by yellow spots, abnormally small leaves, fruit malformation and cracking, reduced plant growth, and high levels of whitefly (Bemisia tabaci MEAM1) infestation were observed in passionflower (Passiflora edulis) orchards in southwestern Bahia, Brazil. The aim of this work was to identify the species of begomovirus infecting the passionflowers, its prevalence in southwestern Bahia, and the spatial and temporal dynamics of the disease. Leaf samples from symptomatic plants collected at 57 orchards located in ten counties were evaluated by PCR for begomovirus infection. Complete nucleotide sequences of DNA-A for two isolates revealed 97 % identity with Passionfruit severe leaf distortion virus (PSLDV). The occurrence of PSLDV in 57 orchards was evaluated based on the presence of characteristic disease symptoms. Approximately 235,000 visually assessed plants exhibited symptoms characteristic of begomovirus infection. Epidemiological studies, conducted in two orchards in Dom Basílio County, showed that disease progress was relatively slow until 121 days after transplanting (DAT), but more rapid in the following 35 days, reaching 100 % infected plants by 156 DAT. The exponential model was fitted to the temporal dynamic of the disease for both areas. An aggregated pattern of diseased plants was predominant for almost all evaluations. It is possible that the primary and secondary spread of the pathogen occurred concurrently during the epidemic progression in both areas, especially late in the season. Containment measures to prevent the virus and the vector from spreading to other passionfruit producing areas in Brazil should be implemented.

Abstract in English:

ABSTRACT: Integrating plant density and nitrogen (N) management is a strategy for improving corn yields, especially for off-season corn production in the tropics. This study tested the hypothesis that increasing plant densities and N rates promotes yield gains for off-season corn production in high-yielding environments. The aim of the study was to investigate the yield performances of two hybrid versions (DKB PRO and DKB PRO3) submitted to three plant densities (55,000; 65,000 and 75,000 plants ha−1) and four N rates (control, 60, 120 and 180 kg ha−1 N). Field trials were undertaken at Uberlândia-MG (site1 and 2) and Pedro Afonso-TO (site 3), Brazil from which data on corn yield parameters were collected and analyzed. Multivariate analysis separated the three trial areas into two groups, presenting high (sites 1 and 2) and low yields (site 3), which were related to weather conditions. There was no influence of a hybrid version or plant densities on crop yields at site 1 or 2. In contrast, there was a positive response to increasing plant densities and the use of DKB PRO3 at site 3. A significant response to N was observed at sites 2 and 3, following a plateau model. Our results suggest that N application rates and plant densities do have the potential to increase off-season corn yields in low yielding environments.