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Fertilization recommendations are frequently proposed by a limited number of calibration experiments conducted in a few regions, with few cultivars. Thus, recommendations concerning nutrients’ critical levels (CLs) and sufficiency ranges (SRs) are not always the most suitable ones. In addition, it is not known whether CL and SR differ when it comes to peach yield and quality variables, such as pulp firmness or total soluble solids (TSS) concentration. CL and SR can be estimated by using Bayesian segmented quantile regression (BSQR) in combination with databases. The aim is to propose nutrients’ CL and SR in soil and in leaves of peach trees grown under a subtropical climate, by combining databases and BSQR models. The dataset comprised 208 observations of Prunus persica cultivars ‘Maciel’ and ‘Chimarrita’, grown in southern Brazil. Models were developed through plateau regression based on BSQR models to measure the association between dependent variables (fruit yield and quality) and nutrient concentrations in the soil and leaves. CL and SR of N and K in leaves recorded values for variables related to fruit quality, pulp firmness, and TSS lower than values recorded for variables related to yield. We show for the first time that CL and SR in leaves for N and K related to yield are different between cultivars. A similar outcome was recorded for CL and SR of N in leaves between growing regions/sites presenting different soil types and climatic variables. CL and SR of N in leaves related to yield were higher in peach trees grown in sandy-soil sites with low organic matter content. This study presents critical advances for the Southern Brazilian peach market, but with implications for the approach presented in the present study (combination of database and BSQR modeling) relevant for application in orchards around the world.

Peach yield production prediction models are little known worldwide. This gap can be filled by combining machine learning techniques and well-documented databases. The aims of this study are: (i) to assess the effect of different prediction variable inputs applied to peach yield prediction models adopted to peach trees grown in orchards under different subtropical climate; (ii) to test the prediction accuracy performance of models calibrated through different machine learning methods; and (iii) to quantify the relevance of peach trees’ yield predictor variables. A database (soil and leaf nutrient content, climatic and plant variables) with information from 208 peach trees (Prunus persica) in production, belonging to the cultivars ‘Maciel’ and ‘Chimarrita’ grown in Southern Brazil, was used. The models were developed by using three machine learning methods: Radom Forest, Multiple Linear Regression, and Support Vector Machine. We demonstrate that the calibration of the models was affected by machine learning method as well as by different predictor variable inputs. The model Random Forest showed the greatest potential to predict peach yield. The variable presenting the greatest relevance to explain peach yield variations was ‘hours of chilling’, which was followed by K and N content in leaves and mean temperature, which recorded relevance of >55%.

Implementing PA techniques in viticulture, commonly referred to as PV, is a relatively recent development in Brazil. This study aimed to evaluate the current adoption of PV tools and techniques by grape growers in the state of Rio Grande do Sul. It also sought to identify the profiles of producers adopting these technologies and the factors influencing their decisions to either adopt or forgo them. An exploratory and descriptive research design was employed, combining qualitative and quantitative methods. Data were collected through an online questionnaire administered to grape growers, yielding responses from 85 producers in the state. Results showed that 57 growers (64%) were adopters of PV, while 28 (36%) were non-adopters, indicating that a majority of viticulturists in the region are incorporating these technologies. Among the PV tools adopted, property management software was the most frequently used, followed by monitoring applications and variable-rate applications of fertilizers and pesticides. The primary barriers to adoption included high initial implementation costs, difficulties in interpreting and applying the data, and limited access to information. Notably, 56% of respondents indicated plans to begin using PV technologies within the next two years, and 22% expressed intentions to expand their current usage, suggesting a growing interest in adoption.

O pessegueiro caracteriza-se por expressivo vigor vegetativo, o que demanda a adoção de práticas de manejo específicas para o seu controle. Entre estas, destaca-se a poda em verde, fundamental para o equilíbrio entre os tecidos vegetativos e reprodutivos, mas que representa um custo elevado devido à intensa necessidade de mão de obra. O trabalho teve como objetivo avaliar paclobutrazol, proexadiona cálcica e trinexapaque-etílico na redução do crescimento vegetativo, na produção e na qualidade de frutos do pessegueiro ‘PS 10711’ cultivados a pleno sol e sob tela antigranizo, na Serra Gaúcha, sul do Brasil. Os experimentos foram conduzidos na safra 2023/2024, avaliando-se os inibidores de biossíntese de giberelinas trinexapaque etílico-TPE, paclobutrazol-PBZ, e proexadiona cálcica- PCA, em duas (AB) ou quatro aplicações (ABCD) na concentração 250 mg L-1: T1- controle (sem aplicação); T2 – TPE (AB); T3 – PBZ (AB); T4 – PCA (AB); T5 – TPE (ABCD); T6 – PBZ (ABCD) e T7 – PCA (ABCD). Foram avaliados o comprimento médio, a massa verde e número de ramos podados, demanda de raleio de frutos, produção e qualidade de frutos e retorno de floração. Em plantas cultivadas a pleno sol, a massa fresca dos ramos na primeira poda foi reduzida em 47,2% e 47,8% nos tratamentos com PBZ. Na segunda poda de verão e na poda invernal, todos os inibidores de giberelinas testados proporcionaram reduções de 20,72% e 39,18%. Sob tela antigranizo, os tratamentos com PBZ reduziram a massa fresca dos ramos removidos na primeira poda em 38,5% e 39,7%. Nos dois estudos, os fitorreguladores não tiveram efeito na produtividade, qualidade de frutos e no retorno de floração, indicando sua viabilidade como estratégia de manejo do crescimento vegetativo.

O objetivo deste trabalho foi avaliar respostas vegetativas e produtivas de videiras ‘Chardonnay’ e ‘Viognier’ submetidas a diferentes épocas de poda seca e indução de brotação na Campanha Gaúcha. Durante o ciclo 2015/2016, utilizou-se um vinhedo comercial conduzido em Guyot duplo em Santana do Livramento/RS. O delineamento experimental foi em blocos casualizados (seis repetições de uma planta), sendo os tratamentos a combinação entre níveis de poda (maio, junho, julho e agosto) e doses de cianamida hidrogenada (CH, 2% e sem aplicação). Avaliou-se fenologia, brotação (% ramos/gema), fertilidade na vara (% ramos com cacho) e produção (kg/planta). A poda em julho antecipou a brotação e a floração, estendendo seus períodos fenológicos e reduzindo a produção por planta em ambas cvs. Entretanto, a poda precoce, principalmente em maio, garantiu similaridade à época tradicional (agosto) em fenologia, fertilidade e produção, em ambos genótipos e sem a necessidade de CH. A aplicação de CH só promoveu benefícios nas podas realizadas em junho ou julho, devido ao estímulo de brotação na ‘Viognier’ e na proporção de ramos férteis na ‘Chardonnay’.

This work sought to evaluate sequential applications of budbreak promoters on hail-netted apple trees in southern Brazil, focusing on the effects at different canopy levels. One or two sprays were applied to ‘Baigent’ and ‘FujiKiku 8’ trees under black net in a commercial orchard in Vacaria/RS. Hydrogen cyanamide (0.34%) with mineral oil (3.5%) was the unique/first application. Mineral oil(3.5%) alone or with hydrogen cyanamide (0.17%, 0.34%), Erger® (1.5%), and Syncron® (1.5%) constituted the reapplications. During the 2017/18 and 2018/19 seasons, phenology, budbreak, fructification, and fruit production were assessed in the lower and upper halves of the canopy of treated and non-treated trees. The budbreak promoters anticipated blooming, generally increased and reduced budbreak and fructification, respectively, without changing production. The upper canopy exhibited delayed budburst/blooming compared to the lower one but showed higher fruiting and advanced harvest in ‘Baigent’. One and two sprays produced similar results and few were the differences among the sequential treatments. Little influences may be attributed to adverse weather conditions, such as water scarcity and low thermal accumulation. The second application is commonly used in the region’s apple orchards, as better outcomes than with just one have been reported. In this context, additional research is required to validate the schemes adopted for hail-netted ‘Baigent’ and ‘Fuji Kiku 8’ trees cultivated in southern Brazil.

Pruning is one of the main management practices for apple cultivation, aiming to achieve a better balance between vegetative growth and production, but it presents a high demand for labor. Thus, mechanical pruning can minimize the operation, requiring technical feasibility and operational performance studies. Precision agriculture provides several technological tools that can be adoptedat different stages of the fruit-growing production process, but reports in thearea are scarce. This study evaluated the spectral behavior of apple plants duringthe production cycle, operational efficiency, and the main quality indices of fruits from plants subjected to different pruning systems using a vegetation sensor. The study was conducted in the 2020/21 and 2021/22 agricultural seasons in a commercial ‘Maxi Gala’ apple orchard under two rootstocks. The treatments consisted of standard pruning, mechanized autumn pruning, mechanized summer pruning, mechanized autumn and summer pruning, and control without pruning. The highest biomass production stages of apple plants influenced the normalized difference vegetation index values in the first growing season. Mechanized pruning treatments took less time to prune one hectare compared to standard pruning. However, no significant difference was observed between the different treatments for fruit yield and the average fresh mass of both rootstocks.Mechanized pruning treatments practically did not alter fruit quality.

Under normal conditions, peach trees bloom and produce fruits abundantly, requiring a large amount of labor for the manual thinning of fruits. Chemical thinning is an alternative that can reduce the need for manual thinning. The objective of this work was to evaluate the 1-aminocyclopropane 1-carboxylic acid (ACC) application to reduce the manual thinning of ‘Chimarrita’ peach trees in the region of Serra Gaúcha, Brazil. The experiment was conducted in the 2022/2023 and 2023/2024 crop years. The experimental design was in randomized blocks, with four replicates and seven treatments, applied at full bloom: unthinned control (only in the first cycle); control (manual thinning); ACCconcentrations of 150, 300, 450, and 600 mg L-1, in addition to 750 mg L-1only in the second cycle; and ethephon concentration of 300 mg L-1. ACC application reducedthe need for manual thinning more effectively compared to ethephon in the first cycle. With increasing ACC concentration, fruit set and the need for manual thinning decreased significantly. However, the increase in ACC concentration, along with manual thinning, resulted in reduced fruit yield in the first cycle. Overall, ACC concentration from 300 mg L-1 reduces the need for manual thinning and shows potential as a chemical thinning agent for ‘Chimarrita’ peach trees.

The use of early budding varieties in regions prone to late frosts may limit production in certain cycles. Since budburst begins in the apical buds, delaying winter pruning can be a management strategy to minimize frost risk. This study aimed to evaluate the effects of different pruning dates during the winter/spring transition in ‘Chardonnay’ and ‘Pinot Noir’ (Vitis vinifera L.) on yield components. Plants were trained using the I-trellis system, and pruned at 15-day intervals from July to October, using cordon spur pruning (two-bud spurs). Pruning conducted after the beginning of September, when apical shoots had more than three expanded leaves, significantly reduced (90%) the yield per plant. This reduction was directly associated with necrosis of primary buds in the base of canes, which stimulated sprouting of secondary or tertiary buds, which do not bear clusters. Delaying winter pruning could be an option for ‘Chardonnay’ and ‘Pinot Noir’, but apical shoot development should be limited to 2-3 expanded leaves, in order to avoid production losses.

Hail netting increases natural fruitlet drop. Mixing lower concentrations of Plant Growth Regulators (PGRs) and spraying on more advanced fruitlets could promote adequate crop load management and improve fruit quality. The objective of this study was to evaluate thinning programs with low concentrations of PGRs sprayed at advanced fruitlet size looking for reducing crop load, enhancing fruit quality, and preserving yield. On 2020/21 and 2021/22, in an orchard covered with hail netting in Bom Jesus-RS, eight programs were tested on vigorous ‘Maxi Gala’: Benzyladenine (BA)+Gibberellic acid₄₊₇ (BA-GA) at full bloom (FB) and BA+Ethephon (ETH) at 15mm; BA-GA at FB and Naphthalene acetic acid+Carbaryl (CB) at 7 mm; BA-GA at FB and BA+CB at 15 mm; ETH+CB at 15 mm and Metamitron (MM)+ETH at 20 mm; BA-GA at FB and BA at 7 mm and MM at 20 mm; MM at 7 mm and MM at 20 mm; Manual Thinning Only; Untreated Control. The treatments containing CB reduced fruit set, although diminished yield unsustainably. All PGR programs improved fruit quality. In conclusion, BA-GA at FB and BA+ETH at 15 mm, and MM at 7 mm and MM at 20 mm reduce crop load, preserve yield and improve fruit quality.