Resumo em Inglês:

ABSTRACT: Adding ionophores to ruminant diets is a strategy to manipulate ruminal fermentation and improve milk yield. This study evaluates the effects of narasin supply to lactating ewes on dry matter intake (DMI), milk yield and composition, and performance of the lambs. Thirty lactating Santa Inês and Santa Inês × Dorper ewes fed a basal diet containing 50 % coastcross hay and 50 % concentrate were randomly assigned to two treatments: control (CON; without ionophores) or NAR (addition of 13 mg narasin kg–1 DM). From the 2nd to 10th week of lactation, DMI of ewes was determined, and once a week, their milk production and composition was measured over a 3-h interval. At the 10th week of lactation, lambs were weaned and their average daily gain (ADG) and starter DMI continued to be evaluated for two more weeks. Narasin supply did not affect weight and DMI of ewes. Ewes fed NAR had greater feed efficiency for milk production and displayed tendency for higher milk yield. Narasin supply reduced milk protein levels, but it did not affect other milk component levels. Ewes fed NAR had greater production of milk urea nitrogen and showed tendency for higher production of fat and total solids. Starter DMI of lambs was not affected by treatments; however, there was a tendency for greater weaning weight for NAR lambs. At the end of experiment, no differences were observed in the performance of lambs. The supply of 13 mg narasin kg–1 to lactating ewes improved milk yield efficiency and tended to increase the weaning weight of their lambs.

Resumo em Inglês:

ABSTRACT: Bos taurus indicus temperament is variable and affects beef tenderization. Our objective was to investigate temperament and performance of non–castrated Nellore and identify groups based on Longissimus lumborum (LL) pH decline as well as beef characteristics produced by those groups. We investigated 94 animals with a subset of carcasses (n = 24) selected based on LL pH at 24 h postmortem (pm) to represent two groups: resistant to pH decline (> 5.8 called pH–Res; n = 10) and normal (< 5.7 called pH–Nor; n = 14). Steaks were fabricated from the LL muscle and randomly assigned to aging (2, 7, 14, and 21 days). Sarcomere length, cooking loss, myofibrillar fragmentation index (MFI), and Warner–Bratzler shear force (WBSF) were determined. Data on temperament were investigated in a multivariate approach, while beef data were compared between groups using the analysis of variance. Rectal temperature at the beginning of the finishing phase and total weight gain were greater and related to animals in the pH–Res group (p < 0.01 and p = 0.03, respectively). Temperature and pH decline curves, sarcomere length, and cooking loss revealed that pH–Res produced beef with lower quality compared to the pH–Nor group. Results for MFI and WBSF did not show differences between groups within each time pm; however, overall steaks from pH–Res were tougher (p = 0.06). Incidence of LL pH between 5.8 and 5.9 at 24 h pm did not compromise the tenderization rate or extension; however, it affected the water holding capacity in this population of Nellore cattle.

Resumo em Inglês:

ABSTRACT: The development of efficient methods for genome–wide association studies (GWAS) between quantitative trait loci (QTL) and genetic values is extremely important to animal and plant breeding programs. Bayesian approaches that aim to select regions of single nucleotide polymorphisms (SNPs) proved to be efficient, indicating genes with important effects. Among the selection criteria for SNPs or regions, selection criterion by percentage of variance can be explained by genomic regions (%var), selection of tag SNPs, and selection based on the window posterior probability of association (WPPA). To also detect potentially associated regions, we proposed measuring posterior probability of the interval PPint), which aims to select regions based on the markers of greatest effects. Therefore, the objective of this work was to evaluate these approaches, in terms of efficiency in selecting and identifying markers or regions located within or close to genes associated with traits. This study also aimed to compare these methodologies with single–marker analyses. To accomplish this, simulated data were used in six scenarios, with SNPs allocated in non–overlapping genomic regions. Considering traits with oligogenic inheritance, WPPA criterion followed by %var and PPint criteria were shown to be superior, presenting higher values of detection power, capturing higher percentages of genetic variance and larger areas. For traits with polygenic inheritance, PPint and WPPA criteria were considered superior. Single–marker analyses identified SNPs associated only in oligogenic inheritance scenarios and was lower than the other criteria.

Resumo em Inglês:

ABSTRACT: Seasonal variations and production factors can influence the quality of grapes. Considering the Sub-middle region of the São Francisco Valley, Brazil, differentiated by production in rainy and warmer periods of the year, the climatic conditions in each season affect the duration of the phenological phases and quality of the grapes. The objective of this study was to characterize the changes in the quality components during maturation of ‘BRS Magna’ grapes on different rootstocks, in rainy seasons under tropical conditions, as a support to define the harvest time. The experiment was conducted in Petrolina, Pernambuco, Brazil, from Jan to Apr 2017 (cycle 1) and Dec 2017 to Apr 2018 (cycle 2) evaluating rootstocks and age of the fruits. Bunches were picked from the start of maturation to the harvest: 49, 56, 61, 64 and 68 days after fruit set (DAF) for cycle 1, and 35, 41, 48, 55, 61, and 66 DAF for cycle 2. In cycle 1 ‘IAC 572’ and ‘Paulsen 1103’ rootstocks provided higher sugar contents in grapes, which was only repeated in cycle 2 for ‘Paulsen 1103’. The accumulation of anthocyanins and yellow flavonoids was favored by ‘IAC 313’ and ‘IAC 572’ rootstocks in cycle 1, and by ‘IAC 313’ and ‘IAC 766’ in cycle 2. A higher content of polyphenols was conferred on ‘IAC 572’ in cycle 1 and on ‘IAC 766’ in cycle 2, which also had a greater antioxidant capacity. Although there were differences between rootstocks, harvesting at approximately 64 DAF maximized grape quality for all treatments.

Resumo em Inglês:

ABSTRACT: A combination of abiotic stresses in sandy soils, such as saline water, saline soil, and lack of nutrients, affects productivity of faba bean. In this study, organic amendments and biostimulants (VIUSID® agro) were used in combination to increase yield of faba bean seed as well as the protein content under a sandy soil and irrigation affected by salt water. Two field experiments were carried out during two successive winter seasons of 2016/2017 and 2017/2018. A split-split-plot design in a randomized complete block was used. The main plots were allotted to the organic amendments, rates of biostimulants (VIUSID® agro) were assigned to sub-plot, and the cultivars were applied to sub-sub-plot. The results showed that the treatment of plant compost applied as an organic amendment and 1.5 L ha–1 of biostimulants (VIUSID® agro) with foliar application significantly increased seed yield of cultivars, Sakha-4, Sakha-1, and Giza-843 by 17.2, 33.0, and 19.8 % respectively, compared to control under a sandy soil and irrigation water affected by salts. The interaction between Sakha-1 cultivar, plant compost, and 1.5 L ha–1 of biostimulants (VIUSID® agro) achieved the optimal combination, providing the highest grain yield, as compared to all other treatments. The combination of these treatments is recommended in order to improve faba bean productivity under similar conditions.

Resumo em Inglês:

ABSTRACT: Olive is one of the most important crops in the Mediterranean Basin, because of the olive oil economic value and its role in characterization of the rural landscape. The strong influence of climatic changes on the modern agriculture and the availability of a large source of genetic variability pose as crucial future challenges. Therefore, safeguarding olive genetic resources becomes fundamental, not only in cultivated forms in ex situ collections, but also in terms of wild trees in their natural habitat. In this study, 174 samples of oleaster collected in different parts of Algeria were analyzed by 16 nuclear Simple Sequence Repeats (SSRs). The analysis showed a huge genetic variability in the oleaster, and the STRUCTURE and Principal Coordinate Analyses (PCoA) highlighted clusterization of genotypes according to their geographic origin and bioclimatic conditions. Genotypes adapted to harsh climatic conditions were identified, which could be useful to enrich the panel of olive genotypes for breeding purposes and preserve genetic diversity of this species from erosion risks.

Resumo em Inglês:

ABSTRACT: Studies on aggressiveness of parasitoids, as assessed by their parasitism against pests, used in biological-control programs are highly important to select the most suitable species and/or strain to control insect pests. The present study investigated whether the egg parasitoid Trichogramma galloi Zucchi, an efficient control agent for sugarcane borer Diatraea saccharalis (Fabricius) in Brazil, could be replaced by Trichogramma atopovirilia Oatman & Platner, a parasitoid easier to mass-produce, since it has been found parasitizing D. saccharalis eggs in the warmest region of Brazil and Argentina. Three strains of the genus Trichogramma were compared: T. atopovirilia (ATP strain) reared on a factitious host Anagasta kuehniella (Zeller); T. atopovirilia isoline ATP-I, reared on D. saccharalis eggs for six generations; and T. galloi, reared on A. kuehniella eggs. We measured parasitism of each strain for 72 h and for the entire life span, parasitism rate per cluster of D. saccharalis eggs, number of parasitoids emerged (parasitism viability), and parasitoid life span. The results confirmed that T. galloi is the best species for D. saccharalis control, showing higher control potential, since parasitism and emergence rate were higher for this species. Although T. atopovirilia ATP-I performed reliably in all parameters, T. galloi exceeded and was the most indicated for mass-rearing in control programs for sugarcane borer.

Resumo em Inglês:

ABSTRACT: Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) is globally disseminated on sugarcane plants. In Brazil, this species has been occurred in the same region as the occurrence of the fungal pathogen causing red rot, Colletotrichum falcatum Went, 1893 (Glomerellales). The objective of this study was to evaluate the hypothesis that this pseudococcid could act as a facilitator of the penetration of the phytopathogen C. falcatum. Species of this mealybug were reared at laboratory to infest sugarcane plants during the experiment. A total of 320 sugarcane plants were utilized for this study, 160 of CTC4 and 160 of RB86 7515 cultivars (cv.), each group subdivided into four treatments: (1) infested with mealybugs; (2) infected with fungal conidia; (3) infested with mealybugs and infected with fungal conidia; and (4) control. Biometrics of the plants, disease symptoms, Total Reducing Sugars (TRS) and Reducing Sugar (RS) were evaluated. To both cv., there was no difference in the height and diameter of the plants in all treatments; and only in “mealybug + fungus”, significant difference on the lengths of the disease lesions inside the plants was found to each cv. as well as the levels of TRS and RS. The presence of the pseudococcid increased the incidence of the disease in both cv., although RB86 7515 was more susceptible to red rot than CTC4.

Resumo em Inglês:

ABSTRACT: Excess sodium in foods is one of the factors in chronic non-communicable diseases whose importance is on the rise. Thus, the aim of this study was to optimize a replacement for sodium in an appetizer-type Mignon cracker on an industrial scale. For this, a mixture design consisting of seven formulations were prepared with sodium replacement ranging between 30 and 60 %. The partial sodium replacement used industrial ingredients (Nutek Salt and PuraQ NA4, and modified KCl and flavor), to assess the impact on sodium content and texture (hardness). No significant differences were found in the hardness attribute. Sodium reduction ranged from 943.43 to 637.21 mg 100 g–1, and formulation 7 (F7) with 60 % replacement could cash in on the “Reduced in sodium” appeal. A sensory Quantitative Descriptive Analysis accessed the sensory profiles of formulations, and significant differences were observed (p < 0.05) in salty taste, sweet taste, bread aroma, and formulation 4 (40 % replacement) but were not significantly different from the formulation in salty taste. In PCA, the first main component showed variability between samples of 84.6 %, while the second axis explained 11.5 % of this variability. Acceptance (taste and overall quality) and purchase intention (above > 70 %) showed that the substitution did not affect consumers’ perceptions, with no significant difference between controls, F4 and F7.

Resumo em Inglês:

ABSTRACT: Selection for heading date has been a decisive factor to increase areas cropped with oats in Brazil. Although important to oat breeders, genomic regions controlling heading date have not been completely identified. The objective of this study was to identify genomic regions controlling oat heading date in subtropical environments. A set of 412 oat genotypes, developed from 1974 to 2015, was assessed for heading date in contrasting environments and genotyped using genotyping–by–sequencing (GBS). Phenotypic and genotypic data were used in single and multi–environment association models. Quantitative trait loci (QTL) associated to heading date were identified on oat consensus groups Mrg02, Mrg05, Mrg06, Mrg12, and Mrg21. Some of the findings confirmed the association of genomic regions with heading date, while others emerge as new candidate regions associated to the trait. The genomic regions identified on Mrg02 and Mrg12 were associated to Vernalization 3 (Vrn3), while the genomic region identified on Mrg21 is associated with Vernalization 1 (Vrn1). The Vrn1 region was detected in Londrina, an environment with reduced vernalization condition, and in the multi–environment model. The results reveal that some genotypes of the panel are responsive to vernalization, increasing the days to heading without this environmental stimulus. Our results provide important contribution for a better understanding of heading date in subtropical environments and a strong basis for marker–assisted selection in oats.

Resumo em Inglês:

ABSTRACT: In the last decades, a new trend to use more refined analytical procedures, such as artificial neural networks (ANN), has emerged to be most accurate, efficient, and extensively applied for mining and data prediction in different contexts, including plant breeding. Thus, this study was developed to establish a new classification proposal for targeting genotypes in breeding programs to approach classical models, such as a complete diallel and modern prediction techniques. The study was based on the standard deviation values of an interpopulation diallel and it also verified the possibility of training a neural network with the standardized genetic parameters for a discrete scale. We used 12 intercrossed maize populations in a complete diallel scheme (66 hybrids), evaluated during the 2005/2006 crop season in three different environments in southern Brazil. The implemented MLP architecture and other associated parameters allowed the development of a generalist model of genotype classification. The MLP neural network model was efficient in predicting parental and interpopulation hybrid classifications from average genetic components from a complete diallel, regardless of the evaluation environment.

Resumo em Inglês:

ABSTRACT: Factors influencing Fusarium head blight (FHB) occurrence and yield losses in winter wheat have extensively been studied through the years; however, reports on the relationship between FHB traits and yield are conflicting. In addition, studies neglected the relationship between FHB traits and thousand-kernel weight (TKW). This study evaluated the variability in the relationship between FHB traits, TKW, and yield under field conditions, using 40 commercial winter wheat cultivars differing in resistance/susceptibility to FHB. In general, the FHB index had greater relation to yield, while Fusarium-damaged kernels (FDK) was more related to TKW. The relationship between yield, TKW, FHB index, and FDK was also determined by resistance/susceptibility of winter wheat cultivars. Fusarium-damaged kernels influenced yield more in moderately resistant (R2 = 43 %) than in susceptible/moderately susceptible cultivars (R2 = 27 %). The influence of the FHB index on TKW was weak (R2 = 9 %) in susceptible/moderately susceptible cultivars and in moderately resistant ones (R2 = 1 %). The potential to predict TKW from yield under pathogen pressure was limited due to the moderate-to-positive correlation between yield and TKW (r = 0.349, p < 0.001). This study provides insights into factors that influence TKW under FHB pathogen pressure and gives direction to more efficient and reliable investigations on grain resistance toward FHB.

Resumo em Inglês:

ABSTRACT: Acerola bushes were observed showing symptoms of shoot proliferation, generalized stunting, yellowing and decline. Since these symptoms are typically induced by phytoplasmas, this survey was carried out with the aim of detecting, identifying and classifying the supposed phytoplasma present in symptomatic bushes. Total DNA was extracted from symptomatic and asymptomatic samples and used in nested PCR conducted by the primer pairs R16mF2/mR1 followed by R16F2n/R2. Amplifications of expected genomic fragments of 1.2 kb revealed the presence of phytoplasma in 73 % of the symptomatic samples. Molecular analyses, using computer-simulated RFLP patterns, similarity coefficient calculation and phylogenetic analysis allowed for classifying the bacterium as a ‘Candidatus Phytoplasma pruni’ – related strain (subgroup 16SrIII-F). The phytoplasma induced the same symptoms in healthy acerola plants inoculated by grafting and showed molecular identity with the strain identified in naturally infected bushes. Although various strains belonging to distinct subgroups within the 16SrIII group have been previously identified in Brazil, this is the first report of the presence of a representative of the 16SrIII-F subgroup in the Brazilian agroecosystem. Considering that phytoplasmas can be systemically distributed throughout the plant and acerola plants are vegetatively propagated, it is recommended that propagation material be obtained from mother plants free of the pathogen.