Valencia Orange Research Articles

Blue LED light improves the antioxidant composition of Valencia oranges during postharvest: Impact on orange juice, pulp portion and peel residue

Valencia orange is the major citrus fruit produced worldwide and its outstanding health benefits are well-established. However, there is a pressing need to further enhance the nutritional quality of fruits and to revalorize the resulting residues, providing benefits for both public health and the environment. Here, Valencia oranges were exposed to blue LED light for 30 days at room temperature in controlled environment chambers, using darkness as a control. Examination of the blue LED light effects was performed focusing on visual aspects, weight loss, organoleptic properties, antioxidant content and oxidation status, together with the analysis of the phytohormonal profile. Blue LED light was found to boost fruit weight loss, particularly through dehydration of the peel, without altering pulp firmness or external appearance. Organoleptic quality, including texture and flavor, as well as total soluble sugar and acidity remained unchanged. Notably, blue LED light increased antioxidant levels, more specifically vitamin C and total phenols in the juice, and enhanced total antioxidant capacity in the peel. This suggests that blue LED light can enhance nutritional quality while preserving organoleptic properties. The increase in antioxidants is likely a protective response against photooxidative stress induced by the blue LED light. These findings highlight the potential of blue LED light to improve postharvest fruit quality with direct health benefits and support a circular economy by enhancing the value of orange peel waste.

Effect of Magnetic Water Irrigating on Fruit Quality and Storability of Valencia Orange

Effect of Magnetic Water Irrigating on Fruit Quality and Storability of Valencia Orange

Valencene ameliorates ox-LDL induced foam cell formation by suppressing inflammation and modulating key proteins involved in the atherogenesis on THP-1 derived macrophages

Atherosclerosis is a distinct risk factor for cardiovascular and cerebrovascular disorders, which are significant contributors to global mortality. It is defined by macrophage-derived foam cell development followed by persistent inflammation, plaque formation, fibrosis and thrombosis. Studies have shown valencene, a sesquiterpene obtained from Valencia oranges, has several health-promoting properties. However, its protective effect against atherosclerosis and foam cell models remains unexplored. The present investigation revealed that valencene treatment suppresses foam cell generation and accumulation of lipids in THP-1-derived cells macrophage models activated with oxidized low-density lipoprotein (ox-LDL), maintained in vitro. The intracellular lipid content was qualitatively and semi-quantitatively analyzed by Oil Red O staining, and the compound's cytotoxicity was assessed through the MTT assay, considering both time-dependent and dose-dependent factors. The RT-qPCR results showed promising anti-inflammatory and anti-oxidant enzyme status upon valencene treatment. The H2DCFDA staining revealed valencene's ability to reduce the oxidative stress induced by ox-LDL. Further, high-throughput proteomic profiling was carried out to identify the target proteins affected by valencene treatment and thereby explore its mechanism of action on foam cell models. Proteomic studies revealed that valencene treatment regulates the expression of several proteins associated with ox-LDL-induced inflammation, defective cholesterol homeostasis and cholesterol efflux pathways.

Estimation of macro and micronutrient concentrations in ‘valencia’ orange leaves at different phenological stages using multispectral image analysis and multiple regression

ABSTRACT This study aimed at estimating the macro- and micronutrient concentrations in leaves of Valencia oranges (Citrus sinensis [L.] Osbeck) through multiple regression analysis using multispectral images and vegetation indices (VIs) selected through the stepwise regression method. The data were collected in a commercial orchard of Valencia oranges in El Barretal, Tamaulipas, Mexico. The leaf samples were analysed in a laboratory to determine the concentrations of N, P, K, Ca, Mg, Cu, Fe, Mn, and Zn using traditional chemical methods; the relative chlorophyll values were obtained using a chlorophyll metre (SPAD502 Plus). Multi-spectral images of the tree canopy were acquired using a UAV equipped with a multispectral camera with five wavelengths (blue, green, red, red edge, and near-infrared); based on these data, 85 VIs were calculated. To select the predictor variables that were most relevant for the model, 90 candidate variables were divided into three groups with 30 VIs grouped by nutrients based on the highest and lowest absolute values found in the correlation matrix. Heteroscedasticity and autocorrelation were also assessed through the Breusch-Pagan and Durbin-Watson tests, respectively. The selected variables were used in multiple regression analysis. The resulting models were validated by mean absolute error (MAE), root-mean-square error (RMSE), mean absolute percentage error (MAPE), and coefficient of determination ( R 2 ). The prediction models showed satisfactory results, with values R 2 between 0.79 and 0.95 and relatively low (<10) MAE and RMSE for all nutrients, except Fe ( < 30 ) in all phenological stages; MAPE values were lower than 0.5% for all nutrients. This study showed that multispectral imaging combined with multiple regression analysis effectively predicts nutrient levels in the leaves of Valencia oranges in various phenological stages. This study presents a new perspective on agricultural systems, offering an effective alternative to assess the nutritional conditions of crops.

The response of Midknight Valencia oranges to ethephon degreening varies in the turning and regreening stages.

Late-ripening citrus plays an important role in the stability of the global citrus industry. However, the regreening phenomenon in Valencia oranges impacts the peel color and commercial value. Ethylene degreening is an effective technique to improve the color of citrus fruits, but this effect may be delayed in regreened oranges. To better clarify this phenomenon, plastid morphology, pigment and phytohormone content in ethephon-degreened Midknight Valencia oranges harvested in different stages were evaluated. Results showed that in fruits harvested at the turning stage, ethephon degreening treatment induced a chloroplast-to-chromoplast transition, and chlorophyll degradation and carotenoid accumulation were accelerated. Conversely, in fruits harvested at the regreening stage, the changes in plastid morphology were minimal, with delayed changes in chlorophyll and carotenoids. Genes related to ethylene biosynthesis and signaling pathways supported these responses. Variations in endogenous auxin, jasmonic acid, abscisic acid and gibberellins could partially explain this phenomenon. The response of Midknight Valencia oranges to ethephon degreening was delayed in the regreening stage, possibly due to the dynamic variations in endogenous phytohormones. © 2024 Society of Chemical Industry.

Yield and Heat Unit Requirements for Several Citrus Cultivars over Several Seasons in Egypt

Citrus cultivars have various temperature needs for development and output at different times from flowering to harvesting, making climate one of the numerous factors that affect citrus’ productivity and quality. In this study, the yield and heat unit requirements for several commercial citrus species over several seasons from 2010/2011 to 2021/2022 in Egypt were investigated. For this investigation, the time of flowering and the time of fruit harvesting were recorded. However, the required heat units from flowering to fruit harvesting were calculated based on daily records of air temperature, taking into account that all results below zero (negative results) are not used and all maximum air temperatures above 35.0 °C (≥35.1) are changed to 35.0 °C. In addition, the base air temperature of 13.0 °C was utilized for determining the required heat units. The results showed that in the experimental area, the overall mean of minimum air temperature, maximum air temperature, air relative humidity, and precipitation during the experimental periods had values of 15.2 °C, 28.70 °C, 59.3%, and 0.3 mm/day, respectively. Moreover, the lowest number of days required from flowering to fruit harvesting was observed to be 290.0 days for Fremont mandarin. Furthermore, the highest number of days required from flowering to fruit harvesting was observed to be 482 and 440 days, respectively, for Bearss Seedless lime and Valencia orange. Our study has highlighted a notable diversity among the investigated citrus cultivars, particularly highlighting specific cultivars that possess high yield. The cultivar that shows the greatest yield over the investigated seasons of the study was Valencia orange with 147.6 kg/tree. Moreover, the average values of the heat unit requirements for Washington Navel orange, Valencia orange, Murcott mandarin, Fremont mandarin, and Bearss Seedless lime were 3112.7, 3628.3, 3221.9, 3027.6, and 4398.4 °C day, respectively. This is the first report regarding the heat unit’s determination for several citrus cultivars grown in Egypt, and we expect this research will provide a new awareness in accepting and discovering novel locations where citrus cultivars can be positively developed in Egypt. It will also prove to be a source of basic information for the development of the citrus crop model.

Digital replica to unveil the impact of growing conditions on orange postharvest quality

The postharvest end-quality of citrus is significantly impacted by pre-harvest factors such as weather, which varies among growing regions. Despite the importance of these factors, the influence of regional weather variations, such as variations in temperature, humidity, wind, vapor pressure deficit (VPD), and solar radiation on postharvest citrus quality, is largely unknown. This study aims to quantify this impact through a physics-driven digital replica of the entire value chain of Valencia oranges, from orchards in South Africa to retail in Europe. Predicted fruit properties data at harvest and hygrothermal sensor data from orchard to retail for different production regions are coupled to a physics-based fruit model to simulate key postharvest fruit quality metrics. These metrics include mass loss, chilling injury, fruit quality index (FQI), remaining shelf life (RSL), total soluble solids (TSS), and titratable acidity (TA). Our digital fruit model reveals that regional weather variability significantly affects fruit quality evolution when comparing data from Nelspruit, Letsitele, and Sunday’s River Valley (SRV). The impact of weather variations is most pronounced in the temperate oceanic climate of SRV compared to the hotter climates of Letsitele and Nelspruit. Our findings indicate that differences in weather conditions between these growing regions impact postharvest mass loss, FQI, RSL, TSS, and TA of Valencia oranges at retail. The impact is up to 10% variation in mass loss and RSL, 4% in TSS, and 1% in TA among oranges grown in different regions. We show that temperature and humidity variations in the postharvest local transport of oranges between different regions largely increase mass loss by up to twofold, FQI by up to ~ 12%, and RSL by up to ~ 15% at retail. Our research also shows that weather temperature is the most important metric during fruit growth affecting various aspects of postharvest orange quality. This study offers valuable insights into the impact of regional weather variations on the quality of oranges available to consumers. These findings could help the citrus industry enhance growing practices, postharvest logistics, retail marketing, and cold chain strategies, thereby improving product quality and consumer satisfaction.

Evaluating the efficacy of moringa aqueous leaf extract as a postharvest treatment for preserving the quality of Valencia oranges

Evaluating the efficacy of moringa aqueous leaf extract as a postharvest treatment for preserving the quality of Valencia oranges

Impact of rice straw mulching on water consumption and productivity of orange trees [Citrus sinensis (L.) Osbeck]

Due to the adverse effect of global climate change on agricultural water management, maintaining soil moisture in the root zone is essential for optimal crop productivity. For effective irrigation, we used organic mulching to increase the yield and water productivity (WP) of Valencia orange in arid/desert climates. Here, the effect of rice straw mulching and irrigation rates [100, 85, and 70% of evapotranspiration reference (ETc)] on nutrient contents, quality, and yield of orange trees was evaluated. Under field conditions, the application of straw mulch significantly increased the concentration of some essential elements and photosynthetic pigments but reduced proline contents in orange leaves. Soil mulching significantly increased fruit and inflorescence retention, and resulted in a higher number and weight of fruit on branches, without compromising their taste or texture, compared to the treatment without mulching. Both irrigation and mulching also affected crop productivity and water use efficiency (WUE). This was evident when yield/fed increased by 22.7–23.8, 20.7–31.5, and 6.2–16.9% under mulching at 100, 85, and 70% ETc, respectively, compared to traditional conditions at 100% ETc without mulch. Although the maximum WUE under rice straw mulch was 5.72–5.84 kg/m3 at 70% ETc, it was 5.31–5.40, and 4.57–4.64 kg/m3 at 85, and 100% ETc, respectively. Organic mulching showed superior results with respect to increasing yields and WP, while saving 15.4% water and comparable benefit/cost with the traditional irrigation when orange trees were irrigated with 85% ETc. Together, this study could be a promising strategy for climate change adaptation and sustainable water management.

Synergistic effect of seaweed extract and boric acid and/or calcium chloride on productivity and physico-chemical properties of Valencia orange.

Many citrus species and cultivars are grown successfully in tropical and subtropical countries, as well as in arid and semi-arid regions with low levels of organic matter and low cation exchange, resulting in lower nutrient uptake by the plant. The essential nutrients needed for citrus flowering and fruit set are limited in winter due to a reduction in transpiration rate, negatively effecting vegetative growth, flowering, yield, and fruit quality. The present investigation was carried out to assess the nutritional status, fruit yield parameters, and fruit quality of Valencia orange trees after foliar spraying of seaweed extract (SW) combined with calcium chloride and boric acid and their combinations in the 2020/2021 and 2021/2022 seasons. The treatments were arranged in a split-plot design (three levels spraying seaweed extract × four levels spraying calcium chloride and boric acid and their combinations × four replicates × one tree/replicate). The results indicated that all of the characteristics measured, including leaf chlorophyll, leaf mineral contents, fruit yield parameters, fruit physical properties, and fruit chemical properties, were significantly affected by the foliar spraying of seaweed extract (SW) combined with calcium chloride and boric acid and their combinations. Although all treatments increased the productivity and the physical and chemical properties of Valencia orange fruits compared to the control, a treatment of 10 g/L SW combined with 0.5 g/L boric acid and 1 g/L calcium chloride produced superior results. This ratio of SW, boric acid, and calcium chloride is therefore recommended to enhance productivity and improve the physico-chemical properties of Valencia orange for greater fruit yield.

ASOCIACIÓN DE LA ABUNDANCIA DE HUEVOS Y NINFAS DE PRIMER INSTAR DE Diaphorina citri CON EL TAMAÑO DE BROTE VEGETATIVO DEL CULTIVO DE NARANJA VALENCIA (Citrus sinensis (L.) Osbeck).

&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;: Currently, there is little information on the abundance of &lt;em&gt;Diaphorina citri&lt;/em&gt; Kuwayama (Hemiptera: Liviidae) eggs and nymphs in the size of vegetative shoots. Such information is relevant for the control of D. citri in early stages of development. &lt;strong&gt;Objective&lt;/strong&gt;: To associate the abundance of eggs and N1 nymphs of &lt;em&gt;D. citri&lt;/em&gt; with the size of the vegetative shoots of the Valencia orange (&lt;em&gt;Citrus sinensis&lt;/em&gt; (L.) Osbeck) crop. &lt;strong&gt;Methodology&lt;/strong&gt;: The study was carried out in the Valencia orange crop in the municipality of Güémez, Tamaulipas. In the field, five categories of shoots were selected under a randomized experimental design. Thirty shoots of each size were confined in a teal tulle bag and 30 shoots of each size were cut to one side of the confined shoot. The number of eggs and N1 nymphs was recorded at 3, 5 and 7 days in each shoot size. The result obtained was subjected to a multivariate analysis of multiple correspondence. &lt;strong&gt;Results:&lt;/strong&gt; In the confined outbreaks, 9 to 27 eggs were recorded in the V2 and V3 outbreaks at three days, and from 71 to 213 eggs in the V4 outbreak at five days. At seven days the number of eggs was like that recorded on day five. In the control shoots, at three and five days, 1 to 3 eggs were recorded in the V5 shoot. At seven days, the number of eggs recorded in shoots V2, V3, V4 and V5 was like that recorded at three and five days. In the confined shoots, at three days no N1 nymphs were recorded in the V5 and V1 shoots. On day five, nine N1 nymphs were recorded in the V2 shoot. While, on day seven the number of N1 nymphs was like that recorded on days three and five. In the control shoots, at three, five and seven days, 1 to 71 N1 nymphs were recorded in the V3 shoot. &lt;strong&gt;Implications:&lt;/strong&gt; The results of this study are useful input for the development of management strategies targeting &lt;em&gt;D. citri&lt;/em&gt; eggs and nymphs to suppress the presence of adults. &lt;strong&gt;Conclusion:&lt;/strong&gt; According to the results, the trials allowed the identification of those categories of vegetative shoots preferential for N1 nymphs and oviposition of adults. This preference may be related to the quality and quantity of photo assimilates present in the different developmental stages of vegetative shoots, which are essential for insect development. &lt;/p&gt;

Characterization of volatile compounds from healthy and citrus black spot-infected Valencia orange juice and essential oil by using gas chromatography–mass spectrometry

Citrus black spot (Phyllosticta citricarpa, CBS) is an important fungal disease that causes rind blemishes and affects quality of citrus fruits. The response of citrus to CBS in terms of volatiles was evaluated using molecular sensory science approaches. Fifty and twenty-one volatiles were identified in the orange juice and essential oil samples, respectively, via gas chromatography–mass spectrometry (GC–MS). The total volatile content in the samples increased after CBS infection, especially in the severe-infection group (SEG) juice and moderate-infection group (MOG) essential oil, which reached the highest levels. CBS enhanced floral, fruity, and off-flavor aromas and decreased the green aroma in citrus juice. Citrusy, floral, and green aromas increased in the CBS-infected essential oil. Six/five potential markers were screened in citrus juice/essential oil, respectively using the orthogonal partial least-square discriminant analysis (OPLS-DA) model. The changes in aroma profile and the difference in infection levels in citrus were attributed to these odorants.

Digital twins to quantify the impact of growing variability on the harvest quality of orange

The quality of citrus fruit is influenced by various growing conditions, including weather. However, the impact of weather differences between growing regions on citrus quality at harvest is not well understood. This study employs a mechanistic-driven digital replica of the growth process of a Valencia orange from fruit set until harvest to quantify this impact. Measured daily temperature, humidity, rainfall, solar radiation, and wind speed data from various orange growing regions of South Africa, including Citrusdal, Nelspruit, Letsitele, and Sundays River Valley (SRV), inform and drive this digital model. The results suggest that the differences in weather conditions between growing regions significantly affect fruit diameter (FD), fruit weight (FW), rind thickness (RT), rind weight (RW), total soluble solids (TSS), titratable acidity (TA), and °Brix/acid ratio of oranges at harvest. The differences between growing regions led to variations of up to threefold for FD, twofold for FW, RT, RW, TSS, °Brix/acid ratio and up to fourfold for TA upon harvest. Particularly, oranges produced from warmer Letsitele and Nelspruit regions are found to be larger, sweeter and less acidic compared to those from coastal SRV upon harvest. The study also reveals the impact of the fruit growth process on the temperature gradient within the fruit, which varies across growing regions. The maximal temperature difference between the fruit core and surface during the growth process ranges from 4 °C to ∼7 °C. These variations in fruit temperature gradient could lead to variations in temperature-driven quality decay of fruit from different climatic regions at the start of their postharvest journey. These findings provide valuable insights for the citrus industry, aiding to optimize practices, harvest planning, and postharvest logistics. The output of this digital twin will help identify areas needing extra precooling to extend postharvest shelf life and minimize quality decay. Real-world use allows growers to schedule harvests based on regional weather conditions.

Direct Organogenesis of Citrus Cultivars from Shoot Tip Nodal Segments.

Citrus cultivar improvement via conventional breeding strategies is impeded by factors related to its reproductive biology. The orange is a hybrid between pomelo (Citrus maxima) and mandarin (Citrus reticulata). Among various orange cultivars, Valencia oranges have a bit of bitter tang mixed in with their sweetness, as Navel oranges are, the most widely cultivated citrus species, quite sweeter, and also don't contain any seeds. Tangelo mandarin orange cultivar is a hybrid of C. reticulata × C. maxima or × C. paradisi. The present study was undertaken to optimize the hormonal composition of the media with regard to plant growth regulators for in vitro propagation of sweet orange cultivars from nodal segment explants. The nodal segment explants were collected from three citrus cultivars, Washington Navel, Valencia and Tangelo. Murashige and Skoog (MS) medium supplemented with sucrose and different concentrations of growth regulators was used for shoot proliferation and root induction, and the optimum medium composition was assessed. The patent for Citrus Tissue Culture was obtained from the Office of Research Affairs, Haramaya University. The results indicate that the highest shoot response was recorded for Washington's navel with maximum shoot proliferation rate (99.75%), shoot number per explant (1.76), shoot length (10.70 cm), leaf number per explants (3.54) after three weeks of culture. In all experiments, no growth was observed for the basal MS medium. Phytohormone combinations of IAA (1.2 mg/L) and kinetin (2.0 mg/L) were found to be the best for shoot proliferation. Among the cultivars, there were significant differences for the highest rooting rate (81.255), root number (2.22), and root length (2.95 cm) variables for Washington Navel. The lowest rooting rate (48.45%), root number (1.47) and root length (2.26 cm) were observed for Valencia. The highest rooting rate (84.90%), root number per microshoot (2.22) and root length (3.05 cm) was on MS medium supplemented with 1.5 mg/L NAA. A comparison of different concentrations of IAA and NAA on root induction of microshoots from nodal segments of citrus cultivars demonstrated NAA was a more effective hormone than IAA.

The Use of Cubic Smoothing Spline Models for Predicting Early Fruit Size in ‘Keenan’ Valencia (Citrus sinensis L. Osbeck) Oranges

Fruit size is an important factor for the sale of fruit in fresh markets. Fruit size prediction early in the growing season would help with planning harvest operations, administering marketing strategies and an advance determination of the proportion of fruit that will be suitable for certain size classes. Fruit diameter growth of ‘Keenan’ Valencia oranges was measured over five consecutive growing seasons (2014–2018) during Stage II (cell enlargement) and Stage III (maturation) periods between January and October. Fruits were randomly selected and tagged from around the tree canopy to record the fruit diameter at fortnightly intervals until harvest. The data were used to develop a fruit size prediction model using the cubic smoothing splines technique. Results indicated that from the fruit growth patterns, an accurate prediction of the final fruit size and distribution were possible during the early Stage II fruit development phase, 6–7 months ahead of the final harvest. It was concluded that fruit size must be 66 mm in diameter by 30 March to attain a fruit size &gt; 77 mm at harvest. This model was tested in 2019 with an accuracy of 97% in predicting fruit size distribution harvest across three size classes.

Citrus black spot caused by Phyllosticta citricarpa found on Valencia oranges in Botswana

Citrus black spot caused by <i>Phyllosticta citricarpa</i> found on Valencia oranges in Botswana

Varied Macro- and Micronutrient Fertilization Rates Impact Root Growth and Distribution and Fruit Yield of Huanglongbing-affected Valencia Orange Trees

Candidatus Liberibacter asiaticus (CLas), which causes huanglongbing (HLB) in citrus trees, has a great impact on tree root health, fruit development, and juice quality. HLB-affected trees have a fibrous root density loss of ∼30% to 80%, resulting in the limited capacity of citrus trees to uptake nutrients. Therefore, this study was conducted for 3 years to 1) assess the temporal changes in root density as a result of varied fertilization, 2) determine dynamics of HLB with regard to root growth and distribution as a result of varied fertilization for Valencia orange trees, and 3) evaluate the impact of varied fertilization rate and method of fertilization on fruit yield for HLB-affected trees. Macronutrients and micronutrients were applied at varying fertilization rates (0×, 1×, 2×, and 4×, of University of Florida guidelines). Root scans were done using minirhizotrons at 0 to 19.1 cm, 19.1 to 40.7 cm, 38.2 to 59.8 cm, and 57.3 to 78.9 cm soil depths. Results obtained from the study showed that root growth and distribution were greater in 0 to 19.1 cm than 19.1 to 40.7 cm to 57.3 to 78.9 cm soil depths. Thus, root growth decreased (P &lt; 0.0004) with increasing soil depth due to variation in nutrient availability for tree uptake. Increased nutrient availability at occurrence of physiological processes in citrus trees also influenced root growth and distribution, resulting in root growth flushes in the months of Nov to early Feb and Jul to early Aug. Fruit yield was significantly different between treatments in 2 of the 4 years of the study (P = 0.001 and P = 0.003), and largely ascribed to soil fertilization of micronutrients compared with foliar. Therefore, at higher fertilization rates, particularly via soil application, nutrient availability was increased, thus promoting root growth and distribution and fruit yield in HLB-affected orange trees.

Water competition in the soil by rootstocks is used to assess drought tolerance in citrus

Brazil is a country focused on agribusiness and is the world's largest producer of orange juice. However, citrus production in certain regions of the world is affected by irregular rainfall, which imposes drought stress conditions and causes behavioral changes in plant survival, growth, and productivity. In this context, the objective of this work was to assess a methodology for the selection of citrus rootstocks tolerant to drought when exposed to water deficit regimes. This work was conceived with prior knowledge of the responses to drought tolerance of three rootstocks: Rangpur Lime (RL), Sunki Tropical (ST) and Sunki Maravilha (SM). The study was carried out with Valencia Orange (VO) scion varieties grafted on these three rootstocks. Two plants were conditioned per pot, forcing competition for available water in the soil, and all combinations were exposed to three different water regimes (irrigated, water deficit, and rehydrated). The hydric and physiological relationships were then evaluated. The results showed that in addition to the availability of water, the association between genotypes in the same pot caused different physiological responses. In view of the contrasting strategies of survival/tolerance adopted by these genotypes in response to water deficit, the combination with RL allowed a higher tolerance, showing less water extraction, lower leaf water potential, and relative water content, as well as an increase in the photosynthetic parameters when combined mainly with SM. The methodology used is a promising and more effective tool for analyses of citrus plants under drought stress conditions.

Effect of Preharvest Treatments with Sodium Bicarbonate and Potassium Silicate in Navel and Valencia Oranges to Control Fungal Decay and Maintain Quality Traits during Cold Storage

The quality of sweet orange (Citrus sinensis L.) is determined by the presence of decay caused by phytopathogenic fungi. This can develop in the field and rapidly spread among oranges during postharvest storage. Currently, the conventional treatments applied to control this problem are chemical fungicides. However, consumers demand eco-friendly and non-polluting alternatives with low chemical residues. Therefore, the aim of this work is the preharvest application of sodium bicarbonate (SB) and potassium silicate (PS) solutions at 0.1 and 1% to Navel and Valencia oranges to elucidate the effect on fruit quality and fungal decay at harvest and after 42 days of storage at 8 °C. Results showed that oranges treated with SB 0.1%, PS 0.1, and PS 1% maintained quality traits at similar levels to the control ones. However, SB 1% reduced firmness and increased weight loss, respiration rate, maturity index, and citrus color index. The total carotenoid content significantly increased in oranges treated with SB 1%, and no differences were observed in the other treatments compared to the control. Total antioxidant activity and total phenolic content decreased in oranges treated with SB at 0.1 and 1%, contrary to the results observed in oranges treated with PS, where both parameters increased. Regarding fungal decay, the best results were obtained in oranges treated with the highest doses of SB and PS. Therefore, the use of SB and PS in preharvest sprays could be an alternative to control fungal decay without affecting orange quality.

Evaluation of the use of glyphosate and legumes in valen-cia orange (Citrus sinensis L. Osbeck), in the north of Vera-cruz: case study.

Evaluation of the use of glyphosate and legumes in valencia orange (Citrus sinensis L. Osbeck), in the north of Veracruz: case study. The objective of the case study was to contribute to the knowledge of herbicides (mainly glyphosate) and legumes of valencia orange producers in northern Veracruz. The study was carried out in the year 2021, with producers from three municipalities located in the north of Veracruz: Papantla, Álamo Temapache and Ixhuatlan de Madero. A total of 55 interviews were carried out. The interview that was conducted was structured around three sections: personal information of the interview respondent, information about herbicides, and information about legumes. The characteristics found in this study indicate that the majority of producers continue to use herbicides, 80% do not know the term glyphosate even though it turns out to be the main active ingredient of several of the herbicides that they apply and despite knowing that these can be very dangerous due to various reasons, they continue to use them without any protective equipment, due to how easy, fast and cheap their application is. However, regardless of everything, the producers are in the best disposition to know and cultivate leguminous plants in their plots to observe their characteristics, benefits and advantages in weed control.