Resumen Introducción. El cultivo de palto es susceptible al estrés hídrico durante la etapa de floración y el crecimiento inicial de los frutos. Este estrés puede ocasionar la caída prematura de los frutos y acentuar la alternancia en la producción. Objetivo. Determinar el índice de estrés hídrico del cultivo (IEHC) en tres cultivares de palto (Hass, Fuerte y Zutano) bajo diferentes condiciones de riego, mediante el empleo de termografía infrarroja. Materiales y métodos. El estudio se realizó en la temporada de otoño del 2023, en la Estación Experimental Agraria Canaán, Ayacucho, Perú. Se seleccionaron 170 árboles de palto de cuatro años en fase reproductiva. Se llevaron a cabo cinco evaluaciones bajo diferentes condiciones de riego, donde se recopiló información después de 14 y 7 días sin riego (SR-14d y SR-7d) y 12, 2 y 1 hora posterior al riego (DR-12h, DR-2h y DR-1h, respectivamente). Se registró la temperatura de las hojas (Th), la conductancia estomática (gs), la humedad del suelo (θ) y el IEHC. Resultados. Los tres cultivares evaluados en este estudio presentaron diferencias significativas de la Th según manejo del riego. Estas variaciones, influenciadas por la temperatura y humedad ambiental, establecieron umbrales de estrés que definieron el IEHC en un rango de 0,34 a 0,96. Al relacionar el IEHC con la gs y θ se obtuvieron valores de R2 = 0,51 y R2 = 0,61, respectivamente. El cultivar Zutano mostró el valor más alto de IEHC en períodos prolongados de restricción de riego y tuvo una baja capacidad para reducir estos valores tras la rehidratación, a diferencia de los otros cultivares. Conclusiones. Se demostró que la termografía infrarroja puede medir eficazmente el IEHC en cultivares de palto, con variaciones significativas observadas en la Th, según la condición de riego. Además, el cultivar Zutano fue el que presentó la menor capacidad de recuperación ante el estrés hídrico.

Abstract Introduction. Avocado cultivation is susceptible to water stress during the flowering stage and initial fruit growth. This stress can cause premature fruit drop and accentuate the alternation in production. Objective. To determine the crop water stress index (CWSI) in three avocado cultivars (Hass, Fuerte, and Zutano) under different irrigation conditions using infrared thermography. Materials and methods. The study was conducted in the autumn of 2023, at the Estación Experimental Agraria Canaán, Ayacucho, Peru. A total of 170 four-year-old avocado trees in the reproductive phase were selected. Five evaluations were carried out under different irrigation conditions, where data was collected after 14 and 7 days without irrigation (WI-14d and WI-7d) and at 12, 2, and 1 hour post-irrigation (AI-12h, AI-2h, and AI-1h, respectively). Leaf temperature (Th), stomatal conductance (gs), soil moisture (θ), and CWSI were recorded. Results. The three evaluated cultivars showed significant differences in Th depending on the irrigation management. These variations, influenced by ambient temperature and humidity, established stress thresholds that defined the CWSI within a range of 0.34 to 0.96. By correlating the CWSI with gs and θ, values of R2 = 0,51 y R2 = 0,61 were obtained, respectively. The Zutano cultivar exhibited the highest CWSI values during prolonged water restriction periods and showed a limited ability to reduce these values after rehydration, differing from the other cultivars. Conclusions. Infrared thermography proved to be an effective too for measuring the CWSI in avocado cultivars, reveling significant variations in Th based on irrigation conditions. Adicionally, the Zutano cultivar was the lest resilient to water stress.

RESUMO O objetivo desta pesquisa foi avaliar a influência de diferentes épocas de plantio e variáveis meteorológicas no desempenho produtivo da mandioca industrial na região do Agreste de Alagoas. Os tratamentos foram cinco datas de plantio, com espaçamento temporal de 25 dias entre elas: D1 - 10 de abril, D2 - 05 de maio, D3 - 30 de maio, D4 - 24 de junho e D5 - 19 de julho. O período experimental foi de abril de 2021 a setembro de 2023, dois ciclos de cultivo. Utilizou-se o delineamento em blocos casualizados, com quatro repetições. As variáveis analisadas foram: dados agrometeorológicas e de crescimento e produção da cultura. Na região do Agreste de Alagoas, entre as estações chuvosa e seca, a ET0 média diária varia de 2,9 a 4,7 mm, respectivamente. A temperatura média do ar é 24,3 °C e atende as demandas térmicas da cultura da mandioca. A precipitação anual é suficiente para garantir a produção de mandioca, porém, há sazonalidade nas chuvas, com período seco da primavera ao verão, o que prejudica plantios mais tardios. Na região do Agreste de Alagoas, o melhor período para o plantio da mandioca é de 10 de abril a 5 de maio, que é o início do período chuvoso da região e garante melhores resultados em: altura do dossel vegetativo (3,2 m), diâmetro do caule (2,8 cm), índice de área foliar (3,0), comprimento máximo (43,1 cm), número (6,6) e rendimento de raízes (72,8 t ha-1), biomassa total (145 t ha-1) e teor de amido (34,3%).

ABSTRACT The aim of this study was to evaluate the influence of different planting times and meteorological variables on the productive performance of industrial cassava in the Agreste region of Alagoas state, Brazil. The treatments were five planting dates, 25 days apart: D1 - April 10, D2 - May 5, D3 - May 30, D4 - June 24 and D5 - July 19. The experiment was conducted from April 2021 to September 2023 (two cultivation cycles), using randomized blocks, with four replicates. The variables analyzed were agrometeorological data, crop growth and yield. In the Agreste region of Alagoas, the average daily ET0 varies from 2.9 to 4.7 mm between the rainy and dry seasons, respectively. The average temperature of 24.3 °C meets the thermal demands of cassava cultivation. Although annual rainfall is sufficient to guarantee cassava production, it is seasonal, with a dry period from spring to summer, which compromises subsequent plantings. In the Agreste region of Alagoas, the best time to plant cassava is from April 10 to May 5, which is the beginning of the rainy season and ensures better vegetative canopy height (3.2 m), stem diameter (2.8 cm), leaf area index (3.0), maximum root length (43.1 cm), number (6.6) and yield (72.8 t ha-1), total biomass (145 t ha-1) and starch content (34.3%).

RESUMO A cultura do tomate cereja é sensível ao déficit hídrico, sendo necessário um adequado manejo da irrigação, principalmente em regiões, cujo regime pluviométrico é irregular. Diante do exposto, o objetivo deste estudo foi analisar a viabilidade do índice térmico para determinação do déficit hídrico em tomate cereja sob diferentes estratégias de irrigação com déficit controlado e uso de condicionador de solo tipo hidrogel. Adotou-se o delineamento experimental em blocos casualizados com arranjo fatorial 5 × 2, em parcelas subdivididas, referentes às cinco estratégias de irrigação (FI - Irrigação plena, RD - Irrigação com déficit hídrico regular, S3 - Irrigação com déficit controlado na fase vegetativa, S4 - Irrigação com déficit controlado na fase de florescimento e frutificação, S5 - Irrigação com déficit controlado na fase de maturação e colheita) com déficit hídrico estabelecido em 50% da evapotranspiração da cultura, e uso do hidrogel (WiH - Com hidrogel, WoH - Sem hidrogel), com quatro repetições, totalizando 40 parcelas experimentais. As variáveis avaliadas foram: número total de flores e frutos, peso total dos frutos e índice térmico do dossel. Aos 60 dias após o transplantio, as estratégias de déficit hídrico regular e déficit hídrico controlado na fase de florescimento e frutificação, sem hidrogel, evidenciaram as maiores médias de índice térmico (0,98; 1,03 e 0,70 °C, respectivamente) e menor potencial hídrico foliar (-0,70; -0,48 e -0,50 MPa, respectivamente). O índice térmico obtido por imagens termográficas é viável para determinação dos efeitos do déficit hídrico no tomate cereja.

ABSTRACT Tomato cultivation is highly demanding on the supply of water throughout its phenological cycle, especially in regions where rainfall is irregular or scarce. Given the above, the objective of this study was to analyze the viability of thermal index for determining water deficit in cherry tomato under different strategies of controlled deficit irrigation and use of a hydrogel-type soil conditioner. The experimental design adopted was randomized blocks in a 5 × 2 split-plot arrangement, referring to the irrigation strategies (FI - Full irrigation, RD - Regular deficit irrigation, with a continuously applied water deficit, S3 - Irrigation with controlled deficit in the vegetative stage, S4 - Irrigation with controlled deficit in the flowering and fruiting stages and S5 - Irrigation with controlled deficit in the maturation and harvest stages), with water deficit established at 50% of crop evapotranspiration, and use of hydrogel (WiH - With hydrogel, WoH - Without hydrogel), with four replicates, and with three plants per plot. The variables tested were: total number of flowers and fruits, total fruit weight and canopy thermal index. At 60 days after transplanting, the regular deficit irrigation and irrigation with controlled water deficit in the flowering, without hydrogel, showed the highest means of thermal index (0.98, 1.03 and 0.70 °C, respectively) and lowest leaf water potential (-0.70, -0.48 and -0.50 MPa, respectively). The thermal index obtained by thermographic images is viable for determining the effects of water deficit on cherry tomato.

Abstract:Disease detection and classification in crops is crucial for the development and growth of the agricultural sector. Traditional techniques and the low technical level applied to crop control generate significant losses for farmers. Computer vision offers solutions in this field; however, current research focuses on using convolutional neural networks (CNNs), which cannot accurately locate the most relevant features in an image. To overcome these limitations, this study proposes a deep learning model based on the Vision Transformers (ViT) architecture to detect and classify early and late blight diseases in potato leaves. This research demonstrates how data augmentation, fine-tuning, and transfer learning techniques can improve the model's performance. The dataset for training and testing was taken from the PlantVillage platform. The report of the proposed model's evaluation metrics reaches an accuracy of 99.18% and an F1 score of 98.7%. The results demonstrate a high level of prediction in potato foliar diseases and evidence of the efficiency of attention mechanisms. It is concluded that the model is an innovative and functional tool for farmers.

Resumen:La detección y clasificación de enfermedades en cultivos es crucial para el desarrollo y crecimiento del sector agrícola. El uso de técnicas tradicionales y el bajo nivel técnico aplicado al control de los sembríos generan grandes pérdidas para los agricultores. La visión por computadora aporta soluciones en este campo, no obstante, las investigaciones actuales se centran en el uso de redes neuronales convolucionales (Convolutional Neural Networks, CNNs), las cuales tienen una limitada capacidad para ubicar de forma precisa las características de mayor relevancia en una imagen. Para superar estas limitaciones, nuestro estudio propone un modelo de aprendizaje profundo basado en la arquitectura de Transformadores de Visión (Vision Transformers, ViT) para detectar y clasificar las enfermedades tizón temprano y tizón tardío en las hojas de papa. En esta investigación se evidencia cómo las técnicas de aumento de datos, ajuste fino y aprendizaje por transferencia permiten mejorar el rendimiento del modelo. El conjunto de datos para entrenamiento y prueba fue tomado de la plataforma PlantVillage. El reporte de métricas de evaluación del modelo propuesto alcanza una exactitud de 99.18% y un puntaje F1 de 98.7%. Los resultados demuestran un alto nivel de predicción en las enfermedades foliares de papa y evidencian la eficiencia de los mecanismos de atención. Se concluye que el modelo se consolida como una herramienta innovadora y funcional para los agricultores.

ABSTRACT Plant factory is a production system characterized by high control and efficiency of the production factors, in which the cultivation of microgreens has increased. Photoperiod and photosynthetic photon flux density (PPFD) are two of the main factors to be investigated in order to obtain maximum yield. In this context, an experiment was conducted in indoor environment to evaluate the influence of photoperiod (12, 16 and 20 h d-1) and PPFD (150, 250, 350 and 450 μmol m-2 s-1) with two harvest times (4 and 6 d of light) on the growth and yield of red cabbage (Brassica oleracea L. var. capitata L.) microgreens. Early harvest, photoperiod and PPFD affected hypocotyl length (HL), cotyledon area (CA) and yield individually and in interaction. Two-day earlier harvest resulted in reductions of 10.0%, 32.0% and 16.5% in HL, CA and yield, respectively. In general, higher PPFD and photoperiod caused decrease in HL and increase in CA and yield. With the combination of these factors, 315 μmol m-2 s-1 with 20 h light promoted the highest yield of red cabbage microgreens. In one year of production, early harvest promotes a greater number of production cycles and higher yield of red cabbage microgreens (616 kg m-2), which was 27% higher than that obtained with harvest carried out 2 d later, when the first leaf appeared.

ABSTRACT Armyworm (Spodoptera litura) is the main leaf-damaging pest of soybean (Glycine max (L.) Merr.) plants. The research aims to assess the resistance response of soybean advanced lines against S. litura, evaluate their agronomic performance, and select the best genotypes based on multiple traits. The research was conducted in Malang, Indonesia. The evaluation for armyworm resistance was based on the free-choice test (FCT) and no-choice test (NCT). Each study utilized a randomized complete block design with 38 soybean genotypes and four replicates. The results showed that the NCT exerted a higher intensity of leaf damage and greater insect pest pressure compared to the FCT. Two soybean genotypes (G17 and G19) consistently demonstrated resistance to S. litura in both the FCT and NCT. Soybean seed yield has a significant positive correlation with plant height, number of filled pods, number of nodes, and number of branches, thus those characters could be used as indirect selection criteria for soybean yield. The selection based on GT Biplot revealed that G38 (resistant-control variety) and G17 had the best performance for resistance to S. litura, but did not exhibit significantly high seed yield. In contrast, G16 exhibited high yield performance but susceptibility to S. litura. The G36 was the best performer for the number of filled pods, number of nodes, number of branches, plant height, and 100-seed weight, despite being relatively less resistant to S. litura. G17 and G19 are promising candidates for breeding programs aimed at developing high-yielding and armyworm-resistant soybean varieties.

ABSTRACT Turcicum leaf blight (TLB) is one of the important diseases in corn (Zea mays L.) plants in Indonesia and causes yield losses about 27% to 90%. One of the controls to suppress TLB is using resistant cultivars. This study aims to evaluate the resistance of hybrid corn genotypes to TLB and determine its effect on the epidemic components of the disease. There are four hybrid corn genotypes HCG11, HCG12, HCG13, and HCG14 that were tested with comparison cultivars used are P36, PAC339, NK8103, BISI18, and Anoman. Observation of TLB severity was carried out when plants were 60, 70, 80, and 90 d after plant. The study was prepared using a randomized group design consisting of nine treatments and repeated three times. The observational data were statistically analyzed and continued with least significant different (LSD) test. Analysis of disease progression models in the field was carried out based on goodness of fit tests, area under disease progress curve (AUDPC) and path analysis. The results showed that only the HCG11 genotype showed a somewhat resistant reaction to TLB disease with disease severity of 33.94%, significantly lower than the comparison cvs. PAC339, BISI18, and Anoman in the 5% LSD test. The epidemic component of the disease also showed that the HCG11 genotype had the lowest AUDPC value and infection rate with the highest protection index against TLB disease. Path analysis showed that relative humidity, temperature, precipitation, and wind speed had a significant effect on the progression of TLB disease.

Abstract The emergence of Machine Learning (ML) technologies and their integration into agriculture has demonstrated a significant impact on disease detection in crops, enabling continuous monitoring and enhancing risk planning and management. This study applied image processing techniques such as thresholding, gamma correction, and the Stretched Neighborhood Effect Color to Grayscale (SNECG) method, alongside ML, to develop a predictive model for identifying five types of rice diseases. The ML techniques used included Logistic Regression, Multilayer Perceptron, Support Vector Machines, Decision Trees, and Random Forests (RF). Hyperparameters were optimized and evaluated through 5-fold cross-validation. In the results, the SNECG method successfully converted images to grayscale, capturing essential features of lesions on rice leaves. The ML models developed with these techniques showed evaluation metrics exceeding 80%, with the RF model (precision = 88.31%) demonstrating superior performance. Additionally, the RF model was integrated into an interface designed for agricultural decision-making. The practical application of the developed model could significantly improve the ability to detect and manage diseases in rice crops.

Resumo A cana-de-açúcar ocupa grande escala territorial no mundo e busca constantemente por mecanismos para monitorar os nutrientes no ciclo de produção da cultura, utilizando métodos não destrutivos. O estudo com objetivo estimar o teor de nitrogênio na folha da cana-de-açúcar foi desenvolvido na safra 2021/2022 sobre dois talhões comerciais de sequeiro cultivares (RB867515 = 50,75 ha) e (CVSP7870 = 48,56 ha) na Usina Energética Serranópolis-Goiás, avaliando a eficiência dos índices bioquímicos de vegetação Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) e Canopy Chlorophyll Content (CCC) processados utilizando modelo de transferência de radiação RTM PROSAIL, comparados aos índices Normalized Difference Vegetation Index (NDVI) e Green Normalized Difference Vegetation Index (GNDVI), processados utilizando modelos matemáticos e razão de bandas. Ambos, baseados em série temporal de dados Sentinel-2 como variáveis de entrada. A validação do Agro-Modelo ocorreu através de análise de tecido foliar coletada em sete avaliações intercaladas durante o período de permanência da cultura no campo. Foi evidenciado a funcionalidade dos quatro índices, destacando o índice bioquímico fAPAR sob a ótica da estatística descritiva (R² = 0,970 e RMSE = 0,46) para o cultivar RB867515 e (R² = 0,940 e RMSE = 0,69) para o cultivar CVSP7870.

Abstract Sugarcane occupies a large territorial scale in the world and is constantly searching for mechanisms to monitor nutrients in the crop production cycle, using non-destructive methods. The study aimed to estimate the nitrogen content in the sugarcane leaf was developed in the 2021/2022 harvest on two commercial fields of dryland cultivars (RB867515 = 50.75 ha) and (CVSP7870 = 48.56 ha) at the Serranópolis-Goiás mill, evaluating the efficiency of the biochemical vegetation indices Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) and Canopy Chlorophyll Content (CCC) processed using the radiation transfer model RTM PROSAIL, compared to the Normalized Difference Vegetation Index (NDVI) and Green Normalized Difference Vegetation Index (GNDVI), processed using mathematical band ratio models. Both were based on a time series of Sentinel-2 data as input variables. The validation of the Agro-Model occurred through analysis of leaf tissue collected in seven interspersed evaluations during the period the crop remained in the field. The functionality of the four indexes was evidenced, highlighting the biochemical index fAPAR from the perspective of descriptive statistics (R² = 0.970 and RMSE = 0.46) for the cultivar RB867515 and (R² = 0.940 and RMSE = 0.69) for the cultivar CVSP7870.

RESUMO: A mineração humana contribui para aumentar a liberação de cromo (Cr) no ambiente. Para a fitorremediação de solo com alto teor de Cr, o girassol é a escolha certa porque o Cr em suas sementes pode ser removido durante a produção de óleo de semente de girassol. No entanto, o alto teor de Cr no solo inibirá o crescimento do girassol, então os agentes de remediação do solo comumente usados com o plantio de girassol são ácido etilenodiaminotetracético (EDTA) e ácido cítrico (AC). Este estudo conduziu uma meta-análise sobre os efeitos do EDTA e AC no desenvolvimento do girassol sob estresse de Cr. Ele fornecerá uma referência para o girassol para melhorar o solo contaminado com Cr ou uma referência para produzir safras em áreas cultivadas poluídas com Cr. Um total de 97 artigos foram encontrados, e sete estudos foram usados nesta meta-análise de janeiro de 1990 a janeiro de 2022. Os resultados mostraram que o tratamento com EDTA não teve efeito no peso das folhas, peso da parte aérea e peso da raiz. O tratamento com AC teve um efeito positivo no peso das folhas, peso da parte aérea e peso da raiz. EDTA e CA aumentaram a concentração de Cr na raiz, folha e broto. Este estudo recomenda a adição de qualquer agente quelante ou ativador, mas o conteúdo de metais tóxicos no solo deve primeiro ser medido cuidadosamente. Infelizmente, neste estudo, não obtivemos uma dose de referência, e pesquisas futuras devem se concentrar neste problema.

ABSTRACT: Human mining contributes to increasing the release of chromium (Cr) into the environment. For the phytoremediation of soil with high Cr content, sunflower is the right choice because the Cr in its seeds can be removed during the production of sunflower seed oil. However, the high content of Cr in the soil will inhibit the growth of sunflower, so the soil remediation agents commonly used with sunflower planting are ethylene diamine tetraacetic acid (EDTA) and citric acid (CA). This study conducted a meta-analysis on the effects of EDTA and CA on the development of sunflower under Cr stress. It will provide a reference for sunflower to improve Cr-contaminated soil or a reference to produce crops in Cr-polluted cultivated areas. A total of 97 articles were found, and 7 studies were used in this meta-analysis from January 1990 to January 2022. The results showed that EDTA treatment had no effect on the leaf weight, shoot weight and root weight. CA treatment had a positive effect on the leaf weight, shoot weight and root weight. EDTA and CA increased the Cr concentration in the root, leaf and shoot. This study recommends the addition of any chelating agent or activator, but the content of toxic metals in the soil must first be measured carefully. Unfortunately, in this study, we did not obtain a reference dose, and future research should focus on this problem.

RESUMO A fruticultura é uma atividade de grande relevância para o agronegócio no Brasil, com destaque para a goiabeira. Entretanto, a deficiência hídrica é um dos fatores limitantes para a produtividade das plantas, onde a utilização de fitohormônios, como o ácido salicílico, tem sido empregado como uma estratégia para mitigar os efeitos do déficit hídrico. O objetivo deste estudo foi avaliar a aplicação foliar de ácido salicílico como atenuador do déficit hídrico em materiais genéticos de goiabeira. O delineamento experimental adotado foi em blocos ao acaso, em esquema fatorial 2 × 2 × 5, considerando dois regimes hídricos (lâminas de irrigação equivalentes a 50 e 100% da evapotranspiração de referência - ETr), dois materiais genéticos de goiabeira (‘Crioula’ e ‘Paluma’) e cinco concentrações de ácido salicílico (0, 1,2, 2,4, 3,6 e 4,8 mM). A aplicação foliar de ácido salicílico na concentração de 2,4 mM promoveu efeito benéfico no crescimento, nas trocas gasosas e na fluorescência da clorofila a da goiabeira ‘Crioula’ sob irrigação com 50% da ETr. O déficit hídrico reduziu o crescimento, as trocas gasosas, o conteúdo de clorofila e a fluorescência da clorofila a da goiabeira. Dentre os materiais genéticos, a ‘Paluma’ obteve maior crescimento, trocas gasosas, teores de clorofila e fluorescência da clorofila a em comparação com a ‘Crioula’ sob irrigação com 50% da ETr sem aplicação foliar de ácido salicílico. A aplicação foliar de ácido salicílico na concentração de 1,2 mM aumentou a área foliar, o número de folhas e a fitomassa seca total no material genético ‘Crioula’ sob 50% de ETr.

ABSTRACT Fruit growing is an activity of great relevance for agribusiness in Brazil, with emphasis on guava. However, water deficiency is one of the limiting factors for plant productivity, so the use of phytohormones such as salicylic acid has been employed as a strategy to mitigate the effects of water deficit. The objective of this study was to evaluate the foliar application of salicylic acid as an attenuator of water deficit in guava genetic materials. The experimental design adopted was randomized blocks, in a 2 × 2 × 5 factorial scheme, considering two water regimes (irrigation depths equivalent to 50 and 100% of the reference evapotranspiration - ETr), two guava genetic materials (‘Crioula’ and ‘Paluma’) and five concentrations of salicylic acid (0, 1.2, 2.4, 3.6, and 4.8 mM). Foliar application of salicylic acid at a concentration of 2.4 mM promoted growth, gas exchange, and chlorophyll a fluorescence of ‘Crioula’ guava under irrigation with 50% ETr. Water deficit reduced growth, gas exchange, chlorophyll contents, and chlorophyll a fluorescence of guava. Among the genetic materials, greater growth, gas exchange, chlorophyll contents, and chlorophyll a fluorescence was observed in ‘Paluma’ compared to ‘Crioula’ under irrigation with 50% ETr without foliar application of salicylic acid. Foliar application of salicylic acid at a concentration of 1.2 mM increases leaf area, number of leaves, and total dry mass in the ‘Crioula’ genetic material under 50% ETr.

RESUMO Os efeitos da restrição hídrica no feijão-caupi podem ser revertidos pelo uso de substâncias elicitoras, tais como o ácido salicílico (AS). Desta forma, objetivou-se avaliar o status hídrico, a integridade celular e o crescimento de cultivares de feijão-caupi sob restrição hídrica e pulverização com ácido salicílico em campo. Quatro cultivares de feijão-caupi (BRS Novaera, BRS Tapaihum, BRS Pujante e BRS Pajeu) foram submetidas a duas lâminas de irrigação (restrição hídrica com 50% de reposição da água perdida por evapotranspiração da cultura - ETc e controle com 100% de reposição da ETc) e três concentrações de AS (0, 276 e 552 mg L-1 de AS), combinados em esquema fatorial 4 × 2 × 3, com três repetições, dispostos em delineamento de blocos casualizados. O conteúdo relativo de água na folha (CRA), vazamento de eletrólitos intracelulares (VE), massa da matéria fresca total (MFT) e taxa de crescimento relativo da parte aérea (TCRA) foram avaliados nos estádios fenológicos V7 e R2. A restrição hídrica reduziu CRA, MFT e TCRA e aumentou VE, enquanto a pulverização com 276 mg L-1 de AS reduziu VE e aumentou CRA, MFT e TCRA das cultivares de feijão-caupi sob restrição hídrica, respostas que variam de acordo com a cultivar e estádio fenológico. A cultivar BRS Novaera mostrou-se mais responsiva a aplicação de AS no estádio V7.

ABSTRACT The effects of water restriction on cowpea can be reversed by the use of eliciting substances such as salicylic acid (SA). Thus, the objective was to evaluate the water status, cellular integrity and growth of cowpea cultivars under water restriction and spraying with salicylic acid in the field. Four cowpea cultivars (BRS Novaera, BRS Tapaihum, BRS Pujante and BRS Pajeu) were subjected to two irrigation levels (water restriction with 50% replacement of water lost through crop evapotranspiration - ETc and control with 100% replacement of ETc) and three concentrations of SA (0, 276 and 552 mg L-1 of SA), combined in a 4 × 2 × 3 factorial scheme, with three replicates, arranged in a randomized block design. Relative leaf water content (RWC), intracellular electrolyte leakage (IEL), total fresh mass (TFM) and shoot relative growth rate (SRGR) were evaluated at phenological stages V7 and R2. Water restriction reduced RWC, TFM and SRGR and increased IEL, while spraying with 276 mg L-1 of SA reduced IEL and increased RWC, TFM and SRGR of cowpea cultivars under water restriction, responses that vary according to the cultivar and phenological stage. The cultivar BRS Novaera was more responsive to the application of SA at the V7 stage.

RESUMO A utilização de mudas de alta qualidade pode ser uma estratégia eficaz na restauração de áreas degradadas. Este estudo teve como objetivo avaliar a produção de mudas de Cariniana estrellensis e Gallesia integrifolia utilizando níveis de sombreamento, e o crescimento dessas mudas em área de reflorestamento. De novembro/21 a março/22, a altura e o diâmetro do coleto das mudas foram avaliados, e após 103 dias, a área foliar, a biomassa, o índice de qualidade de Dickson e a produtividade da água foram determinados. Cada espécie constituiu um experimento distinto, disposto em delineamento em blocos casualizados com quatro tratamentos (níveis de sombreamento de 0; 37,6; 49,4 e 75,8%) e quatro repetições, com dez mudas por repetição. As mudas foram produzidas em tubetes de 280 mL preenchidos com biossólido e irrigadas por gotejamento com sistema automático de acionamento. Considerando a água proveniente da chuva e a irrigação suplementar, as mudas de C. estrellensis receberam, em média, 3,94; 3,60; 3,37 e 2,97 L por planta, enquanto as de G. integrifolia receberam 3,83; 3,63; 3,99 e 3,31 L por planta, respectivamente, durante o ciclo. As maiores produtividades da água foram encontradas nas mudas que receberam maior volume de água. As mudas de C. estrellensis produzidas com sombreamento de 49,4 e 75,8% apresentaram maior crescimento, e um ano após o transplantio alcançaram, em média, alturas de 76,0 e 72,3 cm, respectivamente. As mudas de G. integrifolia produzidas sob sombreamento de 49,4% apresentaram maior desempenho durante a fase de viveiro e melhor adaptação após transplantio.

ABSTRACT The utilization of high-quality seedlings can be an effective strategy for restoring degraded areas. This study aimed to evaluate the production of Cariniana estrellensis and Gallesia integrifolia seedlings using shading levels and the growth of these seedlings in reforestation areas. From November/21 to March/22, the seedlings’ height and stem diameter were evaluated, and after 103 days, the leaf area, biomass, Dickson quality index and water yield were determined. Each species constituted a distinct experiment, arranged in a randomized block design with four treatments (shading levels of 0, 37.6, 49.4, and 75.8%) and four repetitions, with ten seedlings per repetition. The seedlings were produced in 280 mL tubes filled with biosolids and irrigated by drip with an automatic activation system. Considering water from rain and supplementary irrigation, C. estrellensis seedlings received, on average, 3.94, 3.60, 3.37, and 2.97 L per plant, while G. integrifolia seedlings received 3.83, 3.63, 3.99, and 3.31 L per plant, respectively, during the cycle. The highest water yields were found in seedlings that received the largest volume of water. C. estrellensis seedlings produced under 49.4 and 75.8% shading showed greater growth, and one year after transplanting reached, on average, heights of 76.0 and 72.3 cm, respectively. G. integrifolia seedlings produced under 49.4% shading showed greater performance during the nursery phase and better adaptation after transplanting.

ABSTRACT Jambu is important nationally and internationally for its dietary and medicinal use, notably for espilanthol. Despite its versatility, breeding work is scarce. This study aimed to evaluate aerial traits and estimate genetic parameters in jambu accesses to support a breeding program. The experiment was conducted in a greenhouse at the Universidade Federal da Amazônia, Capitão Poço campus. The treatments included 172 genotype clones from seven municipalities in the Northeast mesoregion, obtained from a farmer’s market. Seedlings were cloned and transplanted after three weeks. The design was completely randomized with three replications and 20 cm × 20 cm spacing. At harvest, genotypes were manually removed and taken to the Campus Agricultural Engineering Laboratory to measure 17 aerial part traits. Variance components, genotypic values, and genetic parameters were estimated using REML/BLUP methodology. Genetic and phenotypic correlation matrices and selection gains of 75, 50, and 25% of the genotypes were calculated. Significant genetic variance and high heritability were observed for traits such as plant fresh mass, leaf fresh mass, and stem fresh mass, which are favorable for selection. Indirect selection can enhance leaf and capitula mass without significantly increasing stem diameter. Selecting 50% of the population yields good selection gains without compromising genetic variability.

RESUMO Em sistemas convencionais, o uso de água salina inviabiliza a produção de hortaliças, sendo o cultivo hidropônico uma alternativa promissora em áreas semiáridas, pois minimiza os impactos socioeconômicos. Uma alternativa para mitigação dos efeitos do estresse salino sobre as plantas é a aplicação de ácido salicílico. O objetivo deste estudo foi avaliar o efeito da aplicação foliar do ácido salicílico sobre os aspectos fisiológicos e crescimento de pepino japonês ‘Hiroshi’ sob soluções nutritivas salinas em sistema hidropônico. O trabalho foi conduzido em casa de vegetação. O sistema de cultivo utilizado foi o hidropônico tipo Técnica de Fluxo Laminar de Nutriente - NFT. Os tratamentos consistiram de quatro níveis de condutividade elétrica da solução nutritiva - CEsn (2,1; 3,0; 3,9 e 4,8 dS m-1) e quatro concentrações de ácido salicílico - AS (0; 1,8; 3,6 e 5,4 mM), distribuídos em delineamento inteiramente casualizados em parcelas subdivididas, sendo os valores de CEsn considerados as parcelas e as concentrações de AS as subparcelas, com quatro repetições. Foram avaliadas as variáveis de crescimento, trocas gasosas, pigmentos fotossintéticos, teor relativo de água e extravasamento de eletrólitos no limbo foliar. O AS nas concentrações variando de 3,7 e 4,7 mM aumentou a condutância estomática e a síntese de carotenoides, sob efeito de CEsn de 2,1 dS m-1. A CEsn acima de 2,1 dS m-1 reduziu as trocas gasosas, os teores de pigmentos fotossintéticos, o conteúdo relativo de água e o crescimento das plantas de pepino japonês, 23 dias após o transplantio.

ABSTRACT In conventional systems, the use of saline water makes vegetable production unfeasible, so hydroponic cultivation is a promising alternative in semi-arid areas, as it minimizes socioeconomic impacts. An alternative for mitigating salt stress effects on plants is the application of salicylic acid. The objective of this study was to evaluate the effect of foliar application of salicylic acid on the physiological aspects and growth of ‘Hiroshi’ japanese cucumber under saline nutrient solutions in a hydroponic system. The study was carried out in a greenhouse. The hydroponic system used was the Nutrient Film Technique - NFT. Treatments consisted of four values of electrical conductivity of the nutrient solution - ECns (2.1, 3.0, 3.9, and 4.8 dS m-1) and four concentrations of salicylic acid - SA (0, 1.8, 3.6, and 5.4 mM), distributed in a completely randomized design in split plots, with ECns levels considered the plots and SA concentrations considered the subplots, with four replicates. Growth, gas exchange, photosynthetic pigments, relative water content, and electrolyte leakage in the leaf blade were evaluated. Salicylic acid at concentrations ranging from 3.7 to 4.7 mM increased stomatal conductance and carotenoid synthesis, under ECns of 2.1 dS m-1. ECns above 2.1 dS m-1 reduced gas exchange, photosynthetic pigment content, relative water content, and growth of Japanese cucumber plants, at 23 days after transplanting.