Willian Silva Barros

Saturated hydraulic conductivity ( K _Sat ) is a critical soil property governing hydrological processes across scales, particularly at the soil surface, where it controls infiltration and water movement into deeper layers. Measuring K _Sat in the field is challenging due to high variability, time‐intensive methods, costly equipment, and the need for skilled labor and large samples. Soil heterogeneity and land‐use effects further complicate extrapolation of K _Sat values. This study aimed to (i) identify key‐driving factors that relate K _Sat with hydro‐physical soil attributes and land use systems at a watershed scale, (ii) evaluate the performance of artificial neural networks (ANNs) in predicting K _Sat by comparing them with multiple linear regression (MLR) models, and (iii) assess whether variables derived from principal component analysis (PCA) could improve model K _Sat predictions. ANN and MLR models were developed for a watershed in southern Brazil, using an experimental grid of 178 points. Soil properties (bulk density, total porosity, micro‐ and macroporosity, organic carbon, particle‐size distribution, and K _Sat ) were measured in the 0–20 cm layer, and land use was mapped from satellite imagery. PCA was applied to derive principal components (PCs), which were used as predictors in modeling. Results showed that incorporating PCs significantly improved ANN performance, with the best model (combining total porosity, soil texture, three PCs, and land use) achieving an R ² of 0.70 and RMSE of 0.41 m h ⁻¹ , outperforming the corresponding MLR model. This indicates that K _Sat variability is driven by both soil and land‐use factors and their orthogonal recombinations capturing the dataset's variance structure.

The objective was to evaluate whether the different levels of fertilization with Ca(NO3)2 influenced the growth of rootstocks cultivated in packaging. The plant material used in the experiment was obtained from seeds produced by mother plants of the rootstock cultivar Tsukuba 1, and from two intraspecific F1 hybrids of Prunus persica, derived from reciprocal crossing, selections being NR 0080412 ('Capdeboscq' x ' Flordaguard') and NR 0280401 ('Flordaguard' x 'Capdeboscq'), all with purple leaves. The experimental design was completely randomized, in a 3 x 5 factorial scheme, with three genotypes and five different doses of nitrogen, in the form of calcium nitrate. Five replications were used for each treatment, with the experimental unit consisting of one plant. It was verified that the highest dose of Ca(NO3)2, provided the best quality of the seedlings, which was expressed in the highest DQI, for the three genotypes evaluated, highlighting the seedlings of the 'NR 0080412' selection, which also proved to be more vigorous in relation to the other evaluated genotypes.

Apesar do Rio Grande do Sul se destacar em área cultivada e produção de pêssegos [Prunus persica (L.) Bastch], a sua produtividade média é a mais baixa, comparada a dos outros estados produtores. Dentre os fatores associados a essa baixa produtividade, destaca-se a falta de identificação e seleção de genótipos específicos para uso como porta-enxertos. Oobjetivo do trabalho foi comparar o crescimento de seedlings de porta-enxertos de Prunus persica visando identificar dentro das populações de seedlings indivíduos contrastantes para o caracter vigor. O material propagativo constituiu-se de caroços oriundos de plantas das cultivares de porta-enxertos ‘Capdeboscq’ ‘Tsukuba 1’, ‘Tsukuba 3’, seleções ‘NR 0050303’ e ‘NR 0300402’. Em relação ao desempenho das populações a campo e com base nas variáveis de crescimento e suas correlações, foi possível discriminar indivíduos mais contrastantes quanto ao vigor em quatro das cinco populações avaliadas. Considerando-se as variáveis altura de planta e diâmetro do caule, verificou-se diferenças quanto ao vigor e homogeneidade no crescimento vegetativo entre as populações de porta-enxertos avaliados na condição de campo. As populações de seedlings derivados de ‘Capdeboscq’, ‘Tsukuba 3’ e ‘Tsukuba 1’ apresentaram homogeneidade de crescimento suficientes para serem utilizados na produção de porta-enxertos, via sementes.

Heat stress is one of the major factors reducing potato yield by limiting the plant photosynthesis activity, production and partitioning of assimilates to the sink. Potato wild relatives (Solanum sect. Petota) are a natural reservoir of valuable traits for abiotic stress resistance. However, it is necessary to assess the response of wild potato genotypes based on physiological features such as gas exchange, chlorophyll index and chlorophyll fluorescence that are promising candidates to improve crop photosynthesis under adverse conditions. Multivariate approaches on two factor experimental design were used to select the best performing genotypes for most important traits influencing the photosynthetic activity under control and heat stress treatments. The most important traits to be focused on are net photosynthetic rates, transpiration rates, and stomatal conductance along with effective photochemical yield of PSII, Coefficient of photochemical yield of PSII, electron transport rate and Fv/Fm ratio which are highly associated with heat stress conditions. Solanum commersonii accessions (BGB003, BGB009) are more likely to be tolerant to heat stress, followed by S. tuberosum 2x (BGB091, BGB093) and S. chacoense (BGB101). The assessment of wild accessions for photosynthetic traits under heat stress is a reliable way to discriminate the most promising sources of abiotic stress resistance even though they have unreliable tuber traits for the breeding of the potato crop.

O objetivo deste trabalho foi caracterizar o potencial germinativo de sementes de porta-enxertos de pessegueiro. O material propagativo constituiu-se de caroços das cultivares de porta-enxertos ‘Capdeboscq’ ‘Tsukuba 1’, ‘Tsukuba 2’, ‘Tsukuba 3’, ‘Okinawa Roxo’ e dos híbridos intraespecíficos de P. persica, seleções ‘NR 0280401’ (híbrido F1 derivado do cruzamento ‘Flordaguard’ x ‘Capdeboscq’), ‘NR 0080412’ (híbrido F1 derivado do cruzamento ‘Capdeboscq’ x ‘Flordaguard’), ‘NR 0050303’ (híbrido F1 derivado do cruzamento ‘Capdeboscq’ x ‘Tsukuba 1’) e ‘NR 0300402’ (híbrido F1 derivado do cruzamento ‘Flordaguard’ x ‘Nemaguard’) foram estratificadas em BOD, na ausência de luz, onde permaneceram por até 28 dias. Verificou-se que as sementes das seleções de porta-enxertos ‘NR 0280401’, ‘NR 0080412’ e da cv. ‘Capdeboscq’ requerem menor tempo para a germinação e apresentam maior percentual de sementes germinadas. Genótipos com maturação de frutos mais precoces, o período de armazenamento deve ser menor, devido à perda viabilidade, conforme verificado para ‘Okinawa Roxo’.

To survive in a dynamic environment growing fixed to the ground, plants have developed mechanisms for monitoring and perceiving the environment. When a stimulus is perceived, a series of signals are induced and can propagate away from the stimulated site. Three distinct types of systemic signaling exist, i.e., (i) electrical, (ii) hydraulic, and (iii) chemical, which differ not only in their nature but also in their propagation speed. Naturally, plants suffer influences from two or more stimuli (biotic and/or abiotic). Stimuli combination can promote the activation of new signaling mechanisms that are explicitly activated, as well as the emergence of a new response. This study evaluated the behavior of electrical (electrome) and hydraulic signals after applying simple and combined stimuli in common bean plants. We used simple and mixed stimuli applications to identify biochemical responses and extract information from the electrical and hydraulic patterns. Time series analysis, comparing the conditions before and after the stimuli and the oxidative responses at local and systemic levels, detected changes in electrome and hydraulic signal profiles. Changes in electrome are different between types of stimulation, including their combination, and systemic changes in hydraulic and oxidative dynamics accompany these electrical signals.

A peach breeding program started in 1963, at the Experiment Station of Pelotas, nowadays Embrapa Clima Temperado, whose primary aim was developing cultivars adapted to mild winter conditions. Its first priority was to obtain cultivars of canning type fruits, and over the years, the fresh market cultivars acquired equal importance. This article analyzes the data of 84 fresh market cultivars, obtained in Pelotas, from 1964 to 2017, focusing on the following parameters: time of ripening, fruit development period, average fruit mass, number of fruits per tree, productivity per plant and total soluble solids. First, the data were tabulated, divided into two periods (1964-1984 and 1985-2017), and the descriptive statistical analysis was performed, followed by an analysis via mixed models and estimates of genetic progress via meta-analysis. The main results revealed a reduced fruit development period of the fresh market peaches belonging to that program. It was also observed a significant spread of the time of ripening (end of September or beginning of October until January), with a slight tendency for earliness. Genetic gain was observed for yield corresponding to 1.17 and 2.25% per year, for 1964-1984 and 1985-2017, respectively.

The development process of a new wheat cultivar requires time between obtaining the base population and selecting the most promising line. Estimating genetic parameters more accurately in early generations with a view to anticipating selection means important advances for wheat breeding programs. Thus, the present study estimated the genetic parameters of F2 populations of tropical wheat and the genetic gain from selection via the Bayesian approach. To this end, the authors assessed the grain yield per plot of 34 F2 populations of tropical wheat. The Bayesian approach provided an adequate fit to the model, estimating genetic parameters within the parametric space. Heritability (h2) was 0.51. Among those selected, 11 F2 populations performed better than the control cultivars, with genetic gain of 7.80%. The following populations were the most promising: TbioSossego/CD 1303, CD 1303/TbioPonteiro, BRS 254/CD 1303, Tbio Duque/Tbio Aton, and Tbio Aton/CD 1303. Bayesian inference can be used to significantly improve tropical wheat breeding programs.