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Type 1 ‘Fuji’ stain. Note the stain appears in the area that was previously sunburned, suggesting that high fruit surface temperature induced the stain disorder.
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The emphasis in this paper is on the effects of environmental stresses on apple quality. Apples can be damaged either pre-harvest or post-harvest by certain stresses. In some instances, pre-harvest stress conditions predispose the apple to develop symptoms of a disorder only after picking or storage. Thus, it is important for both growers and packe...
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... Stain. A second disorder that is heat induced is ‘Fuji’ stain. One type of stain appears predominately in the halo area around the sunburned spot on ‘Fuji’ apples (Fig. 4). We have found that incidence of this type stain that appears during cold storage is strongly related to the degree to which apples were sunburned (Fig. 5). This type stain is induced by high FST. There are other types of stain that appear on other parts of an apple, and their causes are under ...
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Citations
... Sunburn and fruit crack are the main limiting factors in litchi cultivation. The extent of sunburn and cracking is affected by various climatic factors, nutritional, genetic and soil condition [1][2]. Damage due to sunburn varies from 0.9-19.13% ...
Litchi (Litchi chinensis Sonn.) is originally from southern China, but due to its higher adoptability and profitability, it is being cultivated in India. In India, litchi is harvested and sold during April-May and fruits have nutritional and economical values. Litchi cv. 'Rose Scented' is highly preferred in India for its taste, but sunburn and fruit cracking are a major drawback for its cultivation. Studies were conducted to quantify the severity of sunburn and incidence of fruit cracking. Fruits first affected by sunburn and burnt outer skin or peel or cuticle part, later turned into cracking. So sunburn acted as a predisposition to fruit cracking in 'Rose Scented'. Thus, sun burn and cracking can be seen in the same fruit. These types (cracked fruit with sunburn) of fruits were 8.26%, 19.58% and 43.25% in 2017, 2018 and 2019, respectively. Lower thickness of cuticle and spongy layer and higher temperature of fruit surface in burnt and cracked fruit may be accountable for fruit burning and cracking. A close correlation was observed between sunburn, cracking and weather situation over two months. A positive relationship was found between maximum temperature, sunburn and fruit cracking.
... Mean proportions of total fruit (N 5 3) with sunburn exceeding SB2 based on the scale developed bySchrader et al. (2004), which would result in cullage in a commercial setting in 2021 and 2022 with no netting, netting deployed until harvest, or nets retracted 10 d before harvest and then either evaporative cooling (EC) or no EC applied. Letters indicate significant differences among means determined using a Tukey's honestly significant difference test (a 5 0.05). ...
Protective netting and evaporative cooling are commonly used for sunburn protection in apple ( Malus domestica Borkh.) orchards in semiarid environments such as central Washington state. Sunburn is caused by a combination of solar radiation and heat, which can cause significant economic losses. Although protective netting and evaporative cooling can be effective for preventing apple sunburn, netting can also introduce new risks, including red color development on the fruit surface. This study evaluated whether retracting netting before harvest improves red color development and/or changes sunburn risk compared with leaving netting in place until after harvest. An experiment was conducted that compared three netting treatments: 1) netting from June until harvest, 2) netting retracted 10 d before harvest, and 3) no netting all season combined with the presence or absence of evaporative cooling. Fruit was harvested and assessed for sunburn incidence and external quality characteristics immediately after harvest. In retracted netting treatments, red color was higher when netting was retracted compared with the nonretracted controls, and sunburn risk did not increase with netting retraction. Evaporative cooling reduced sunburn incidence. Retractable netting can be used to minimize the loss of fruit to sunburn while allowing a full light environment that promotes red color near harvest. There is no inherent increase in sunburn risk from netting retraction, and the proportion of fruit with red color improved.
... After allowing sunburn symptoms to develop for 72 h posttreatment, physiological and physical measurements were taken from 5 to 10 individuals from each treatment group in each replicate. Sunburn browning severity was called, using a previously developed scale of SB0-SB4 (Schrader et al. 2003). Photographs were taken of each fruit on a white background. ...
... Fig. 1b, c;Schrader et al. 2003). ...
Apples grown in high heat, high light, and low humidity environments are at risk for sun injury disorders like sunburn and associated crop losses. Understanding the physiological and molecular mechanisms underlying sunburn will support improvement of mitigation strategies and breeding for more resilient varieties. Numerous studies have highlighted key biochemical processes involved in sun injury, such as the phenylpropanoid and reactive oxygen species (ROS) pathways, demonstrating both enzyme activities and expression of related genes in response to sunburn conditions. Most previous studies have focused on at-harvest activity of a small number of genes in response to heat stress. Thus, it remains unclear how stress events earlier in the season affect physiology and gene expression. Here, we applied heat stress to mid-season apples in the field, and collected tissue along a time course - 24, 48, and 72 hours following a heat stimulus - to investigate dynamic gene expression changes using a transcriptomic lens. We found a relatively small number of differentially expressed genes (DEGs) and enriched functional terms in response to heat treatments. Only a few of these belonged to pathways previously described to be involved in sunburn, such as the AsA-GSH pathway, while most DEGs had not yet been implicated in sunburn or heat stress in pome fruit.
... There is also a range in severity of sunburn browning that can occur within and across cultivars. Scales of severity have been developed for both green and bicolor apples, where a score of 0 indicates undamaged fruit, and scores of 1-4 range from slight browning to severe browning ( Figure 1) [25,26]. Since small blemishes to the fruit surface can lead to discarding those fruit, even small portions of affected fruit surface can lead to higher grades of sunburn severity. ...
Orchard systems have drastically changed over the last three decades to high-density plantings that prioritize light interception that is evenly distributed throughout the entire canopy. These conditions allow the production of fruit with a high red color that meets consumer demands for uniformly colored fruit without external disorders. However, these systems also expose a higher proportion of fruit to full-sunlight conditions. In many semi-arid apple production regions, summer temperatures often exceed thresholds for the development of fruit sunburn, which can lead to >10% fruit losses in some regions and some years. To combat this, growers and researchers use sunburn mitigation strategies such as shade netting and evaporative cooling, which bring a different set of potential fruit quality impacts. Often, there is a tradeoff between red color development and fruit sunburn, particularly for strategies that affect light intensity reaching the fruit surface. In this paper, we review agronomic and environmental factors leading to reductions in red color and increases in sunburn incidence, along with advancements in management practices that help mitigate these issues. Furthermore, we also identify gaps in knowledge on the influence climate change might have on the viability of some practices that either enhance red color or limit sunburn for apple orchards in semi-arid environments. There is a need for cost-effective management strategies that reduce losses to sunburn but do not inhibit red color development in bicolor apple cultivars.
... All of the fruits picked from each measurement tree were placed in separate bins; a subsample of 30 apples was randomly selected from this population for further assessment. Sunburn damage was assessed according to the 6-point Schrader McFerson system; category "0" was considered undamaged; category "1" was considered mildly damaged; categories "2" to "5" were considered severely damaged (Schrader et al. 2003). Analyses of fruit height and diameter, firmness, soluble solids, titratable acidity, and dry matter were conducted according to standardized methods utilized by the Tree Fruit Breeding Program at Su-RDC (e.g., Hampson et al. 2013). ...
In 2021, an unprecedented heat event caused widespread damage to tree fruit crops across western North America. In a preliminary trial conducted that summer in an apple (var. ‘Fuji’) orchard in the Okanagan Valley, British Columbia, a calcium carbonate-based foliar protectant reduced severe sunburn by 9% and fruit asymmetry by 17% but had no other effects on fruit quality, water stress or leaf gas exchange. With climate change, extreme heat events are projected to become more frequent and extreme. Foliar protectants show potential for preserving fruit quality, but further research is urgently required to optimize their use in Canada.
... Size and quality of apples are also influenced by summer temperatures and light conditions. Several authors have highlighted and reviewed the effect of average summer temperatures on internal quality attributes, e.g., titratable acid content, anthocyanin content in the peel, sugar-acid ratio, but also to morphological characteristics, e.g., firmness [22] [23], and physiological disorders at ripening stage, e.g., Fuji stain, lenticel marking [24], bitter pit [25], and watercore [26]. During the development of the epidermal tissue, unfavorable climatic conditions can cause stress leading to hysteresis of specific metabolic systems resulting in peel dysfunction or aberrations [27]. ...
Choosing the most-suitable locations for a given apple variety is a difficult and wide-ranging decision for farmers and all other involved parties in apple production. The selected apple variety has substantial influence on the profitability of an orchard. With KULTIVAS, we therefore propose an approach for a data-driven decision support system to deal with an ongoing problem in apple cultivation. In this project, we use selected historical apple production and quality data, modern data management systems, algorithms, machine learning techniques, and a multidisciplinary approach involving experts from different disciplines, such as agronomy, physiology, climatology, and computer science, to assess the site-specific suitability for the cultivation of specific apple varieties. Our developed prediction model is based on spatially interpolated climate and topography data, as well as apple production and quality data from different cooperatives. It can estimate various crop parameters, such as apple size, color, and yield, using available spatial information on climate. The quality of the prediction of our statistical model depends on the coverage of the possible climatic and topographic variability in the areas by the training data sets. Predictions that fall outside this confidence range have limited predictive power. It is planned to improve the results of this study with data from additional locations and more advanced algorithms for better geographical matching of sorting data, as this data set heavily influences the results.
... All the early ripening genotypes were susceptible to sun burn while late ripening genotypes were tolerant to sun burn which is limiting factors in production of early cultivars of litchi (Mandal and Mitra 2016). The incidence and severity of sunburn depends upon climatic factor, cultivars, hormonal, nutritional and soil moisture (Schrader et al. 2003). Pericarp of fruit affected by sun burn lose was found to extensibility and developed micro cracks. ...
... The incidence of sun burn also coincided with period of rapid pulp growth which exerted pressure on the surface of peel thereby causing fruit cracking. Sun burn in grape was characterized by loss of chlorophyll (Merzlyack et al. 2002) and brown lesions (Schrader et al. 2003). Fruit cracking in litchi is unique and entirely different from other crops because sun burn incidence predisposes fruits to pericarp cracking. ...
... The higher burning of litchi fruits on south side of the tree canopy was due to high temperature (Kumar et al. 2001). UVB radiation plays a bigger role than visible light (Schrader et al. 2003). The rise on fruit temperature dramatically increased the pressure exerted by the pulp on the skin and decreased skin stiffness and strength, increasing the incidence of splitting (Lang and During 1990). ...
Thirty genotypes were evaluated for incidence of sun burn and fruit cracking. Fourteen genotypes were affected by sun burn with maximum in genotype IC-0615602 (54.48%). Sixteen genotypes were free from sun burn which possessed maximum cuticle thickness ranging from 1.99 mm in IC-0615585 to 1.95 mm in IC-0615595 whereas susceptible genotypes possessed least thickness of cuticle. Tolerant genotypes possessed maximum fruit skin strength, number of leaflet per shoot, densely spaced leaflet, minimum length of rachis and petioles. Fruit Surface Temperature (FST) of susceptible genotypes was higher than that of tolerant genotypes. Fruits located in the south direction were highly affected to sun burn to the tune of 62.45 % whereas north direction showed least (43.46 %). Positively correlation of sun burn was found with FST (0.83), leaflet interval (0.69), petiole length (0.49) and negatively correlation with cuticle thickness (-0.69), spongy layer thickness (-0.79), fruit skin strength (-0.68) and total leaflet (-0.65). Bangladesh J. Bot. 51(1): 37-43, 2022 (March)
... To assess the proportion of high-quality fruit free of sunburn, bitter pit, or poor color, 60 fruit were collected from the three representative trees in each orchard. Fruit quality assessments included sunburn analysis following the Washington Tree Fruit Research Commission sunburn scale for bi-color fruit based on [38]. Red overcolor was graded based on <25% coverage, 25-50% coverage, 50-75% coverage, or 75-100% coverage. ...
Soil health assessment can be a critical soil testing tool that includes biological and physical indicators of soil function related to crop and environmental health. Soil health indicator minimum data sets should be regional and management goal specific. The objective of this study was to initiate the steps to develop a soil assessment tool for irrigated orchard soils in Central Washington, United States including defining objectives, gathering baseline data and selecting target indicators. This study measured twenty-one biological, physical and chemical properties of soils in irrigated Central Washington apple orchards including indicators of water availability, root health, fertility, and biological activity. Soil factors were related to fruit yield and quality. Principal components and nonlinear Bayesian modeling were used to explore the relationship between soil health indicators and yield. Soil indicators measurements in Washington state orchards varied widely but generally had lower organic matter, available water capacity, wet aggregate stability and higher percent sand than in other regions. Linear mixed effects models for available water capacity and percent sand showed significant effects on yield, and models for root health ratings and Pratylenchus nematodes had moderate effects. The minimum dataset of soil health indicators for Central Washington orchards should include measurements of water availability (available water capacity, percent sand) and of root health (bean root health rating, Pratylenchus nematodes) in addition to standard fertility indicators to meet stakeholder management goals.
... secha (Schrader, 1997;Schrader et al., 2003;Yuri et al., 2000). Altas temperaturas y mayores valores de radiación disminuyen la conductividad estomática de manzanas, y en ausencia de transpiración los frutos pierden capacidad para disipar el calor; el uso de mallas media sombra disminuye los índices de estrés (Mañueco, M. et al., 2015). ...
... La temperatura máxima del aire se correlaciona de forma positiva con la máxima TSF, y dentro de los factores meteorológicos involucrados es el de mayor correlación (Schrader et al., 2003). TSF = a + b* Tmax: siendo TSF = Temperatura superficial de frutos y Tmax = Temperatura máxima del aire. ...
Apple sunburn risk characterization based on meteorological indexes for irrigated valleys of Northern Patagonia. Sunburn damage in pome fruit trees is one of the main discard actors in the irrigated valley of Río Negro and Neuquén. There is variability between the different seasons in the proportion of damaged fruit, and also the degree of incidence of meteorological factors is a function of the physiological characteristics of the crops (genotypes) and the structural management technologies applied (training systems, rows orientation, pruning and canopy handling). Temperature, radiation and winds were analyzed and characterized, as the main meteorological indices that triggered this physiopathy and the orientation of the plantations as the main management factor (regardless of varietal susceptibility). Finally, the probability of occurrence of events
was calculated from the relative empirical frequencies (F.E.R) of the three grometeorological indices previously analyzed.
... At harvest, total fruit from the five trees of each replicate were visually classified according to the extent of sun damage based on a scale developed by Schrader et al. (2003). The following categories were considered: no sunburn (without damage, NB), slight sunburn (yellow discolouration, SB-1), slight-moderate sunburn (bronze discolouration with lenticel damage, SB-2), moderate sunburn (browning, SB-3), and severe sunburn (browning with necrosis, SB-4) ( Fig. 1); the amount of fruit with sun damage was expressed as a percentage. ...
Netting has been widely used in recent years to protect apple fruit from solar injury. There is little information on the biochemical aspects underlying the effectiveness of netting against sunburn in apples. The objective of this study was to quantify the effects of netting on polyphenols, anthocyanins, and antioxidant activity in apples with different sunburn degrees in terms of fruit peel color variation. Orchards of ‘Gala Brookfield’ and ‘Fuji Raku Raku’ apples were covered in red and pearl nets (providing 20% shading), respectively. Uncovered trees served as controls for the experiments. Spectral light transmission was measured under the nets from 350 to 1700 nm. Photosynthetically active radiation (PAR), ultraviolet radiation (UV), and fruit surface temperature (FST) were evaluated from 20 to 175 day after full blooming. Red netting increased the amount of red (600–700 nm) and blue (400–500 nm) wavelengths of the visible spectrum. Both red and pearl nets reduced infrared (900–1700 nm) transmission by 8%, which resulted in a decrease around 5 °C in FST. Similarly, PAR radiation was reduced by 25 and 21% on average, while the reduction in UV radiation reached 29 and 25% with red and pearl netting, respectively. In moderate (browning; SB-3) and severe (browning with necrosis; SB-4) damage categories, sunburn decreased 15% in ‘Gala Brookfield’ under red netting, and only 4% in ‘Fuji Raku Raku’ under pearl netting. In ‘Gala Brookfield’, red netting significantly increased anthocyanin content and ferric ion-reducing antioxidant power (FRAP) antioxidant capacity for the SB4 sunburn category. In contrast, pearl netting significantly reduced the amount of polyphenols, anthocyanins, and the FRAP antioxidant capacity in SB-4 sunburn group of ‘Fuji Raku Raku’ apples. Collectively, our results suggest that sun protection provided by netting result in changes in the composition and antioxidant capacity of fruit peels, whose response varies depending on the cultivar and type of net used.
