1 Introduction

Cherry production faces growing instability because its most sensitive phenological stages increasingly coincide with spring frost, persistent rainfall, hail, and heat events, all of which can sharply reduce fruit set, increase cracking, and impair final marketable yield. Sweet cherry is repeatedly described as highly susceptible to adverse climatic conditions, especially during bloom and ripening, when frost injures flowers and rainfall promotes cracking and secondary quality losses (Ruiz-Aracil et al., 2024). Climate-based risk analyses further show that precipitation, frost, and high temperatures affect cherry orchards differently across phenological stages and landscapes, with risk often intensifying in inland and higher-elevation production zones. Long-term phenological research also indicates that earlier flowering under warming conditions can increase exposure to late spring frosts, particularly in highland environments, even when regional trends are not uniform across all sites (Hájková et al., 2023). In Germany, blossom has been projected to advance by as much as 17 days, underscoring how warming can shift vulnerability windows rather than simply remove frost risk. Recent field observations in stone fruit systems likewise show that frost damage depends not only on minimum temperature but also on event duration, concurrent rain or snow, and developmental stage, with longer cold episodes causing stronger losses in flowers, ovaries, and productivity (Pryakhina and Upadysheva, 2025). For commercial orchards, these hazards are especially consequential because cracked or diseased fruit rapidly lose fresh-market and even processing value, making production stability a central agronomic and economic concern rather than a purely physiological one. Grower-oriented and review studies from multiple regions therefore converge on the need for adaptive orchard technologies that can buffer microclimate, reduce direct weather injury, and sustain fruit quality under increasingly erratic conditions.

Among these adaptive strategies, rain-shelter cultivation has emerged as one of the most practical structural approaches for reducing weather-related losses in cherries because it directly limits exposure of flowers and fruit to excessive precipitation and hail while modifying the canopy microenvironment. In rainy production regions of Southwest China, uncovered Chinese cherry orchards can suffer yield losses of up to 90%, whereas rain shelters have been increasingly adopted to protect reproductive organs and fruit during the period from flowering to harvest (Tian et al., 2019). Experimental evidence shows that shelter cultivation can dramatically reduce fruit cracking, from 95% in open-field controls to about 4% under polyethylene cover, while increasing fruit size and producing an approximately fourfold yield increase. These gains are not explained only by physical rain exclusion. Physiological studies report that sheltered trees often develop larger leaves, higher chlorophyll and carotenoid contents, altered light-response traits, and improved capacity to utilize weak light, helping maintain carbon gain under reduced radiation conditions. At the molecular level, shelter covering has been associated with earlier or stronger expression of genes involved in photosynthetic light harvesting, electron transport, carbon fixation, and anthocyanin biosynthesis, which helps explain observed improvements in assimilate accumulation and fruit coloration under protected cultivation. Fruit quality responses are also generally favorable, including increases in soluble solids, sugars, ascorbic acid, and anthocyanins and reductions in titratable acidity in sheltered cherries. At the same time, the value of rain-shelter cultivation should not be treated as unconditional. Covers can reduce photosynthetically active radiation and lower net photosynthetic rate when transmittance is insufficient, so shelter design must balance protection with adequate ventilation and light penetration. Evidence from other fruit crops reinforces both the promise and the caution: rain shelters have increased marketable yield and reduced disease in strawberry and improved fruit sweetness and appearance in pear, yet they have also been linked to declines in some soil fertility indicators and rhizosphere microbial diversity, implying that long-term protected systems require refined nutrient and soil management. Economic analyses similarly show that the benefit of orchard covering is region-specific, with stronger expected returns in southern-central Chile than in northern-central production zones, and with profitability sensitive to yield, market price, fruit firmness, and the local relevance of rain versus frost protection (Rojas et al., 2021).

This review therefore aims first to synthesize the major climatic threats affecting cherry production stability, with emphasis on the interaction between phenology and episodic frost, rainfall, hail, and other extreme events that determine spatial and seasonal risk. Second, it examines the development and application value of rain-shelter cultivation as a climate-adaptation technology, focusing on its effects on cracking control, yield formation, canopy photosynthesis, fruit quality, and grower returns. Third, it highlights the main limitations and knowledge gaps that still constrain broader optimization, including shelter-induced light reduction, site-specific profitability, and the need to integrate protected cultivation with cultivar selection, canopy management, water-fertilizer regulation, and long-term soil stewardship. In structure, the review proceeds from the climatic and biological basis of instability in cherry orchards, to the mechanisms and agronomic effects of rain-shelter systems, and finally to unresolved issues and future directions for stable, high-quality cherry production under climate change. Such a framework is warranted because growers increasingly report harmful shifts in temperature, precipitation, and extreme weather, and most expect adaptation to be necessary, while recent syntheses emphasize that future orchard success will depend on combining structural protection with broader innovation in climate-smart fruit production.

2 Climatic Stress Factors Affecting Cherry Production and Stability

2.1 Effects of abnormal precipitation on cherry growth and development

Abnormal precipitation is one of the most direct climatic threats to cherry production because excess rainfall near ripening sharply increases fruit cracking and reduces the proportion of marketable fruit. In extreme seasons, this effect can become catastrophic: rain-induced cracking has been reported to make more than 80% of output unmarketable, and severe rainfall in southeastern Spain in May 2023 substantially compromised commercial sweet cherry yield (Garrido-Auñón et al., 2026). Seasonal exposure is critical, since cracking tends to intensify in the later stages of fruit development, when cherries become physiologically more susceptible to excess water and cuticular failure. Multi-year work also shows that the extent of cracking is strongly season-dependent, so similar orchards can perform very differently from year to year under shifting rainfall patterns.

The damaging effect of abnormal precipitation is mediated by several water-uptake pathways and fruit traits rather than rainfall amount alone. Mechanistic analyses indicate that cracking begins with water uptake at the fruit surface, followed by localized cell bursting, epidermal weakening, and visible crack formation. Other work shows that different crack types can arise from different pathways, with root-zone water influx favoring deep side cracks and canopy wetting favoring shallower cuticular cracks around the stem or apex. Susceptibility also varies strongly among cultivars and fruit characteristics, reflecting differences in skin properties, firmness, fruit size, and genetic background (Quero-Garciá et al., 2021). This complexity explains why heavy rain is a major trigger but not a complete predictor of damage, and why precipitation shocks translate into unstable orchard performance rather than a uniform loss pattern.

2.2 Disease risks induced by high-humidity environments

High-humidity environments increase disease pressure in cherry orchards by extending wet periods, favoring pathogen development, and amplifying the consequences of rain-related fruit injury. In brown rot, disease severity rises when weather is favorable for Monilinia development, and epidemiological monitoring in Spanish orchards identified March and April as the critical infection period. Brown rot at harvest was positively associated with the number of consecutive high-humidity days, and more than 11 days with relative humidity above 80% in each fortnight of the critical period was linked to complete crop infection in that system (Larena et al., 2021). These results show that persistent humidity is not only a background condition but a measurable epidemic driver that can destabilize year-to-year fruit health.

Humidity-related risk is compounded by the fact that cracked fruit becomes highly vulnerable to secondary infection and postharvest decay. Cracked cherries are notably susceptible to invasion by fungal pathogens such as Monilinia, Alternaria, and Botrytis, and once cracking occurs the fruit effectively loses fresh-market value. Powdery mildew adds a second major disease constraint: it is described as a detrimental or even the most important fungal disease of sweet cherry in major production regions, with foliar infections typically preceding fruit infections by about 42 days. Humid environments also intensify postharvest rot, with Fusarium-associated cherry spoilage reported as most severe under humid conditions and further enhanced by fruit wounds (Lombe and Zhang, 2025). Together, these findings indicate that high humidity reduces production stability both before harvest, through orchard epidemics, and after harvest, through rapid decay of already damaged fruit.

2.3 Limitations of climate fluctuations on cherry production stability

Beyond single rainfall or humidity events, broader climate fluctuations constrain cherry production stability by altering phenology, chilling fulfillment, reproductive success, and interannual yield regularity. Climate instability in sour cherry systems has been associated with rising temperatures and highly variable moisture during critical developmental periods, leading to disrupted physiological processes and more nonstandard fruit (Pendrak, 2026). For sweet cherry, profitable production depends on high and consistent bud break, yet conventional chilling-requirement estimates may underestimate the winter chill actually needed for commercial productivity. This means that warming winters can threaten orchard viability before obvious crop failure appears, because insufficient chill reduces the floral conversion needed for stable yields (Figure 1).

Climate fluctuations also limit stability by increasing variability across years, sites, and phenological stages, making grower outcomes less predictable and more dependent on local adaptation. In southern Russia, sweet cherry yield remained low and irregular despite generally suitable growing conditions, with annual average yield ranging from 1.5 to 53.2 kg per tree as weather stressors altered bud and flower survival (Dolya and Fomenko, 2025). Economic modeling in Chile similarly found that orchard covers improved expected returns in southern-central zones but not clearly in northern-central ones, showing that the value of climate protection depends on local risk structure and the relative importance of rain versus frost. More broadly, recent reviews conclude that climate change is already reducing cherry production through rising temperatures, environmental stress, and technical constraints, especially in regions with limited adaptive capacity. Overall, climate fluctuations limit cherry production stability by combining acute weather shocks with slower shifts in orchard suitability, so stable production increasingly depends on integrated protection and adaptation strategies.

3 Regulation of Orchard Microenvironment by Rain-Shelter Cultivation

3.1 Regulation of water conditions by rain-shelter facilities

Rain-shelter facilities first regulate orchard water conditions by physically intercepting rainfall, reducing direct wetting of the canopy and fruit surface while also lowering evaporation demand from the orchard floor. Review evidence in sweet cherry indicates that protected environments tend to reduce soil water evaporation and increase water availability relative to open-field systems (Salvadores and Bastías, 2023). In Mediterranean cherry production, high tunnels also produced higher soil matric potential and higher midday stem water potential than open-field cultivation, indicating improved tree water status under cover.

This water-buffering effect extends from soil moisture to whole-tree water uptake behavior. Modern protected sweet cherry systems can create lower vapor pressure deficit, reduced wind exposure, and altered transpiration demand, all of which change sap flow patterns and irrigation requirements (Stone et al., 2022). In a ventilated rain-covered system, daily sap flow was about threefold lower than in an adjacent netted system, showing that shelter structures can substantially reduce tree water use over the season.

3.2 Effects of rain-shelter cultivation on temperature and light environments

Rain-shelter cultivation consistently modifies the thermal and radiative environment of the orchard canopy, although the magnitude depends on cover design and weather conditions. In sweet cherry in central Chile, rain cover reduced total solar radiation by 50%-60% while slightly increasing upper-canopy air temperature and decreasing relative humidity (Pino et al., 2023). A broader review likewise identifies photosynthetically active radiation, temperature, relative humidity, and wind speed as the main environmental variables altered by cover systems, with direct consequences for gas exchange, flowering, fruit set, and fruit quality.

These effects are not uniform across systems. In Australia, self-ventilating rain covers reduced daily maximum temperature by about 4°C under warm conditions but had limited effects during cooler periods, suggesting that well-ventilated structures can buffer heat extremes without strongly altering the microclimate in mild weather (Song et al., 2026). By contrast, other cherry studies report lower light intensity together with more stable temperature and humidity under polyethylene shelters, and this reduced light can increase leaf chlorophyll and weak-light-use efficiency even when net photosynthetic rate declines.

3.3 Changes in orchard ecological environment under rain-shelter conditions

Rain-shelter cultivation also reshapes the orchard ecological environment by altering humidity exposure, pathogen pressure, and the biological conditions of aboveground and belowground habitats. Work on protected cherry production has long shown that covers improve marketable yield largely by reducing cracking, disease, and fruit decay associated with late-season rainfall. Earlier sweet cherry experiments similarly found that the beneficial effect of covering was especially strong for reducing fruit decay, even when some cover types produced only limited changes in other quality traits (Børve et al., 2003).

Beyond disease suppression, rain shelters can shift orchard microbial ecology and soil-associated biological processes. In grape, rain-shelter cultivation reduced leaf humidity, increased canopy temperature, and decreased light intensity, while also lowering downy mildew incidence and reducing several pathogen-associated genera in the phyllosphere (He et al., 2025). Related evidence from pear shows that rain-shelter cultivation improves fruit appearance and quality while reducing pests and diseases, and it also changes rhizosphere bacterial community structure, indicating that sheltered orchards should be viewed as biologically reassembled systems rather than simple rain-exclusion structures. Together, these findings show that rain-shelter cultivation influences cherry production stability not only by excluding rain, but by reorganizing water relations, canopy climate, and the broader orchard ecological environment.

4 Effects of Rain-Shelter Cultivation on Cherry Growth Development and Yield Formation

4.1 Effects on vegetative growth and tree architecture

Rain-shelter cultivation commonly promotes vegetative growth by increasing leaf area and shoot extension, although the resulting canopy is often structurally softer and more shade-adapted. In Chinese cherry, sheltering increased leaf area by 23.0% to 26.87% at 55 days after flowering, while leaf thickness decreased by 17.67% to 19.7%. In sweet cherry, leaves under shelter were also larger, but leaf thickness, palisade tissue, sponge tissue, and stomatal density were reduced, indicating anatomical adjustment to the lower-light environment. A Chilean orchard study likewise found greater shoot length and leaf area under rain cover across cultivars, with shoot length increasing by 28% to 58% and trunk cross-sectional area increasing significantly in ‘Rainier’ (Pino et al., 2023).

These structural responses suggest that rain shelters shift tree architecture toward a more vigorous but less compact canopy, which may require corresponding pruning and training adjustments. Field observations in sweet cherry showed that new shoots became longer but thinner under rain-shelter cultivation, while leaf chlorophyll content increased despite reduced photosynthetic rate. Broader reviews of covered cherry systems conclude that lower total photosynthetically active radiation can weaken the reproductive-vegetative balance even when diffuse light benefits some physiological processes, so pruning, crop load regulation, irrigation, and nutrition must be adapted to each cover type (Salvadores and Bastías, 2023). High-tunnel work also indicates that integrating protected systems with dwarfing rootstocks and precise fruiting-wall architectures is central to optimizing tree development under cover.

4.2 Effects on flowering and fruit-setting processes

Rain-shelter cultivation modifies flowering and fruit set mainly by changing canopy temperature, humidity, and radiation during bloom, and these effects are not uniformly positive. Review evidence indicates that temperature shifts under covers can alter flowering and flower set, sometimes negatively affecting yield while also accelerating fruit ripening and enhancing cell division in developing fruit (Salvadores and Bastías, 2023). The same review notes that reduced fruit set in cherry is strongly tied to unsuitable minimum and maximum temperatures during flowering because cool conditions suppress bee activity and pollen performance. In practice, high tunnels in Chile advanced full bloom by 4 days, showing that shelters can shift reproductive timing even when total yield remains unchanged.

The reproductive outcome depends on whether the modified microclimate stays within a favorable range during bloom and early fruit development. In ‘Santina’ sweet cherry, high temperatures and relative humidity inside high tunnels during bloom and fruit set reduced fruit yield, indicating that cover-induced forcing can become detrimental when thermal and humidity loads are excessive (Blanco et al., 2021). By contrast, protected forcing systems in Germany advanced harvest by 7 to 19 days and were associated with productive outcomes across training systems, implying that controlled microclimate can improve reproductive efficiency when matched with suitable canopy design. Practical tunnel management also often includes active pollination support, such as the introduction of bumblebee hives at bloom, reflecting the recognized need to stabilize pollination under partially enclosed conditions.

4.3 Effects on fruit yield formation

The clearest effect of rain-shelter cultivation on yield formation is the improvement in marketable yield through reduced cracking, fruit drop, and weather damage. In Chinese cherry, sheltering reduced cracking from 95% in the control to about 4% and produced an approximately fourfold increase in yield, while fruit size and mean fruit weight also increased significantly. In sweet cherry under high tunnels in Chile, cracking losses fell from 19% in the open to 3% under cover, and covered fruit were larger even though total yield remained about 15 kg per tree in both treatments (Blanco et al., 2019). Three-year orchard trials in Greece similarly found that protective films significantly lowered cracking in all cultivars and increased marketable yield without adverse effects on fruit quality.

Even so, higher marketable yield does not always translate into higher biological yield, because shelter benefits are strongly conditioned by rainfall intensity, cultivar, and cover properties. A Czech multi-cultivar study found that covering was profitable and effective for cracking reduction, but cracking still occurred under cover depending on genotype and year (Suran et al., 2019). Another Greek study reported no effect of covering on productivity or mean fruit weight in most cultivars despite better cracking control, showing that the main benefit can be loss avoidance rather than yield stimulation. More intensive high-tunnel systems nevertheless report very good mature-tree yields of about 18 t/ha together with improved young-tree growth and large fruit size, supporting the view that shelters can enhance yield formation most effectively when combined with optimized canopy structure, rootstock choice, and microclimate management. Overall, rain-shelter cultivation influences cherry growth development and yield formation by stimulating vegetative expansion, shifting reproductive timing, and most consistently protecting yield from rain-induced loss. Its value for production stability is strongest when shelter structure, cultivar, and orchard management are aligned with local climate risk.

5 Effects of Rain-Shelter Cultivation on Cherry Fruit Quality and Marketability

5.1 Improvement of external fruit quality traits

Rain-shelter cultivation most consistently improves the external commercial quality of cherries by reducing rain-induced cracking, which is the main visible defect limiting marketability. In Chinese cherry, sheltering reduced cracking from 95% in open-field trees to about 4% under cover while also increasing fruit size and mean fruit weight. This advantage is commercially important because cracked cherries lose market value and also become less suitable for storage and transport. Similar multi-cultivar work in the Czech Republic showed that rain-protective covering remained a profitable option for reducing cracking even though cultivar-dependent cracking could still occur under cover (Suran et al., 2019).

Improvement in external appearance under shelters is less uniform than cracking control, because cover-induced light reduction can either support more uniform maturation or impair skin color development depending on cultivar and management. Under plastic cover in southern Chile, reflective ground film increased the proportion of fruits larger than 32 mm and raised the share of mahogany-colored cherries in the lower canopy, indicating that color and size uniformity can be improved when additional light is supplied within the covered system (Muñoz-Alarcón et al., 2025). By contrast, rain cover in central Chile negatively affected fruit firmness and sugar content and reduced anthocyanins, carotenoids, and antioxidant capacity in the bicolored cultivar ‘Rainier’, showing that covers can weaken external color expression in light-demanding genotypes. In another sweet cherry study, fruit under roof or high-tunnel covers showed slightly less intense color, confirming that external appearance benefits depend on balancing rain protection with adequate light and ventilation.

5.2 Regulation of internal fruit quality characteristics

Rain-shelter cultivation can improve several internal quality characteristics of cherry fruit, especially in rainy regions where open-field fruit quality is heavily constrained by water injury. In Chinese cherry, sheltered fruit showed higher total soluble solids, soluble sugars, ascorbic acid, and anthocyanins, while titratable acidity decreased relative to the control. Transcriptomic evidence supports this physiological pattern, because key genes in phenylpropanoid and flavonoid pathways were up-regulated earlier in sheltered fruit, which was conducive to higher anthocyanin accumulation. These findings suggest that, under suitable shelter conditions, quality improvement is not only a consequence of rain exclusion but also of altered fruit metabolism during development.

However, the internal quality response is not uniformly positive across production systems, and some covered orchards show weaker sweetness, acidity, or firmness because reduced radiation and altered mineral balance can dilute or slow desirable ripening traits. In central Chile, rain cover negatively affected fruit firmness and sugar content across cultivars, and total phenol content decreased in all three tested cultivars. A Mediterranean high-tunnel study likewise found that soluble solids concentration and titratable acidity were not improved by protected cultivation, while fruit from covered trees were significantly larger but softer than fruit from uncovered trees (Blanco et al., 2021). Work in covered ‘Regina’ orchards further showed lower soluble solids in fruit from protected trees, likely due to lower solar radiation and a dilution effect associated with larger fruit size.

5.3 Effects on postharvest quality and storage performance

Postharvest performance under rain-shelter cultivation depends on the initial quality achieved at harvest and on the specific cover configuration, with some systems extending shelf life and others mainly shifting the pattern of quality loss during storage. Storage studies on rain-sheltered sweet cherries showed that color parameters and texture traits decline progressively at room temperature, while total soluble solids and weight loss increase during storage. Among four cultivars grown under rain-shelter cultivation, ‘Black Pearl’ had the best overall postharvest quality and the longest shelf life, indicating that cultivar choice remains a major determinant of storage success under protected production (Zhang et al., 2022). Cover design also matters, because fruit from an arched shelter showed the best quality and the longest shelf life compared with other shelter types.

The main postharvest limitation is that sheltered fruit are still highly perishable, and some cover systems can reduce firmness or alter storage disorders even when they improve field marketability. In ‘Santina’, cherries from high tunnels were softer at harvest and after 45 days of cold storage, although by the end of shelf life most quality differences between covered and uncovered fruit had narrowed. Another two-season study found that reduced firmness, lower titratable acidity, and slightly weaker color under covers were maintained after 30 days of modified-atmosphere storage (Palma et al., 2023). More broadly, cracked fruit have shorter storage and shelf life, so the marketability benefit of shelters still remains substantial because preventing cracking reduces the entry point for rapid postharvest deterioration. Overall, rain-shelter cultivation improves cherry fruit quality and marketability most reliably through cracking reduction and protection of external commercial value, while its effects on internal composition and storage performance are more cultivar- and system-dependent.

6 Physiological and Molecular Mechanisms Underlying Enhanced Stress Resistance in Cherries through Rain-Shelter Cultivation

6.1 Water regulation and osmotic balance mechanisms

Rain-shelter cultivation improves water regulation first by moderating orchard water supply and tree water status under protected conditions. In sweet cherry under high tunnels, covered trees showed higher soil matric potential, higher midday stem water potential, and higher stomatal conductance than uncovered trees, indicating a less stressful hydraulic state under shelter. This shelter effect is physiologically important because rain-shelter systems alter the growing environment, especially the water condition, which has been proposed as a key driver of adaptive responses in ‘Manaohong’ cherry (Ran et al., 2022). Even when reduced irrigation was imposed, covered trees maintained yield and fruit quality while increasing water productivity, suggesting that protected systems buffer water stress rather than simply increasing water use.

At the cellular level, enhanced stress resistance under rain shelter appears to rely on osmotic adjustment through compatible solutes and amino-acid metabolism. Classical Prunus work showed that water stress lowers osmotic potential in both leaves and roots, while soluble carbohydrates and potassium are the main solutes involved, with sorbitol accounting for most water stress-induced solute accumulation Recent metabolomic evidence in sweet cherry leaves under rain-shelter cultivation showed upregulation of proline and several other amino-acid-related metabolites, supporting the view that shelter-grown trees maintain cell turgor by strengthening osmotic regulators (Zhan et al., 2024). The same study concluded that rain-shelter plants exhibited improved tolerance to drought stress by regulating osmotic regulators and signaling substances in amino acid metabolism.

6.2 Mechanisms of oxidative stress mitigation

A second mechanism is the mitigation of oxidative stress caused by excess water, altered light, or secondary drought stress. In cherry rootstocks exposed to short-term waterlogging, reactive oxygen species accumulated rapidly, confirming that rainfall-related root-zone stress directly disturbs cellular redox balance (Jia et al., 2019). During this response, catalase, peroxidase, and glutathione reductase were activated as ROS scavengers, showing that cherry stress tolerance depends on a functional antioxidant enzyme system. Genotypic differences were also clear, because P. pseudocerasus and P. cerasus × P. canescens maintained higher ROS-scavenging capacity and survived waterlogging better than the more sensitive P. mahaleb.

Under rain-shelter cultivation, oxidative protection appears to be integrated with acclimation to low light rather than simple avoidance of stress. In sweet cherry, sheltered leaves had higher non-photochemical quenching while the photosystem II reaction center remained undamaged, indicating that excess excitation energy was safely dissipated instead of causing photoinjury. Transcriptomic analysis in Chinese cherry further showed upregulation of genes encoding photosynthetic antenna proteins and electron transport components under shelter, consistent with a coordinated balance between light harvesting and photoprotection under modified canopy radiation. Metabolomic work also notes that rain shelter affects antioxidant systems and that sheltered leaves accumulate flavonoids and related metabolites that help reduce low-light stress damage (Zhan et al., 2024).

6.3 Defense metabolism and molecular response mechanisms

Rain-shelter cultivation also enhances stress resistance through broad reprogramming of defense metabolism at the transcript and metabolite levels. Comparative transcriptomics identified 38,621 differentially expressed genes in leaves and 3,584 in fruits under shelter covering, indicating a large-scale adaptive response rather than an isolated pathway effect. Among the induced pathways, genes involved in carbon fixation, chlorophyll synthesis, and carotenoid synthesis were expressed earlier or more strongly in sheltered leaves, supporting improved CO₂ use and organic matter accumulation under the altered microclimate. This molecular adjustment helps explain why sheltered cherry plants can maintain function under lower radiation while still supporting growth and fruit development.

Defense metabolism in sheltered cherries also includes polyamine biosynthesis and phenylpropanoid-flavonoid activation, both of which are strongly linked to stress tolerance. Shelter covering increased expression of the spermidine synthase gene CpSPDS and raised putrescine, spermidine, and spermine contents, with spermidine in alabastrums reaching 3.29-fold the level in unsheltered trees; this response was associated with improved fruit setting (Wu et al., 2020). Related work on CpADC showed that this polyamine-pathway gene is induced under sheltered conditions and that higher putrescine accumulation is associated with lower malondialdehyde and higher proline under stress, supporting a mechanistic link between polyamines, membrane protection, and osmotic defense (Ran et al., 2022). In parallel, sheltered cherry fruits and leaves showed stronger phenylpropanoid and flavonoid metabolism, including earlier upregulation of PAL, C4H, 4CL, CHS, CHI, DFR, and ANS and increased flavonoid accumulation, which appears to strengthen both antioxidant capacity and general stress resistance. Taken together, rain-shelter cultivation enhances cherry stress resistance by stabilizing plant water relations, reinforcing redox homeostasis, and activating polyamine- and flavonoid-centered molecular defenses.

7 Case Studies: Effects of Rain-Shelter Cultivation on Cherry Production Stability in Different Regions

7.1 Applications of rain-shelter cultivation in major cherry-producing regions of China

In China, rain-shelter cultivation has been adopted most clearly in rain-prone southern and southwestern production zones, where spring rain and hail strongly constrain cherry expansion. In Guizhou, Chinese cherry is widely grown under subtropical monsoon conditions with about 1220 mm annual precipitation and 88% relative humidity, and shelter covering was specifically developed there to reduce fruit drop and cracking during the period from bloom to harvest. The same regional context is described more broadly for Southwest China, where conventional unsheltered production can lose up to 90% of yield from rain and hail, making shelters an important local production technology rather than an optional refinement.

Adoption has also spread in other Chinese cherry regions beyond Guizhou as production expanded from traditional Bohai Bay orchards into wetter inland zones. A Chinese review notes that new production areas such as Shanxi, Sichuan, and the Yunnan-Guizhou Plateau have expanded rapidly, but fruit appearance, taste, firmness, and shelf life are easily damaged by rain-induced cracking and subsequent decay. Recent metabolomic work similarly states that sheltered cultivation has been widely used for sweet cherry in southern China to protect flowers and fruit from excessive rainfall and hail, indicating that the technology is now embedded in regional adaptation strategies rather than limited to isolated experiments (Zhan et al., 2024).

7.2 Changes in cherry production indicators under rain-shelter cultivation conditions

Across Chinese case studies, the strongest and most consistent production effect of rain shelters is the stabilization of marketable yield through cracking control. In Guizhou Chinese cherry, cracking fell from 95% in the control to about 4% under one- and two-year shelter treatments, and this translated into an approximately fourfold increase in yield together with larger fruit size and weight. In another Chinese sweet cherry study, sheltered orchards maintained a cracking rate below 5%, significantly lower than the open field, while temperature and humidity became more stable under the cover.

Other production indicators show a more mixed but still commercially relevant response. Shelter systems in China generally increase leaf area and chlorophyll content and can improve weak-light use, but they may also reduce net photosynthetic rate when film transmittance is too low, indicating that stability gains depend on matching cover design to canopy light demand (Zhang et al., 2021). Similar tradeoffs appear internationally: in central Chile, rain cover increased shoot length and leaf area but negatively affected fruit firmness and sugar content, whereas in Taizhou, rain-avoiding shelter reduced transpiration and increased water use efficiency, suggesting that production stability is often improved first through risk reduction rather than uniformly better quality traits.

7.3 Case summary and implications for commercial production

International case studies show that the commercial value of rain-shelter cultivation depends on local climate risk, cultivar response, and the economic structure of the orchard. In southern-central Chile, decision analysis projected major benefits from polyethylene covers, with a 90% net present value range from −33,605 to 595,447 USD, and concluded that orchard protection may become necessary for secure future production (Rojas et al., 2021). By contrast, benefits were not clearly positive in northern-central Chile, showing that shelter investment is most justified where rainfall risk near harvest is a dominant constraint rather than where other hazards drive profitability.

The broader commercial lesson is that covers are most valuable when they are integrated into a whole-orchard system rather than treated only as a rain barrier. Economic analysis from Italy found that cover structures produce more secure and stable yields at farm and supply-chain levels, although their investment cost and environmental burden must be considered in orchard design (Ghelfi and Palmieri, 2022). This system perspective is consistent with broader evidence that covers remain a profitable option for reducing cracking in Europe, and with low-cost Chinese recommendations that simple awnings can control cracking to within 0.3% while also reducing bird damage. Overall, the case studies show that rain-shelter cultivation most reliably improves production stability in regions where rainfall near bloom or harvest is the main cause of cracking, decay, and marketable-yield loss. Its commercial success depends on regional climate, suitable shelter design, and coordinated management of light, ventilation, and cultivar performance.

8 Optimization Strategies and Future Perspectives of Rain-Shelter Cultivation

8.1 Development of intelligent rain-shelter facilities

Future rain-shelter systems for cherries should increasingly shift from fixed plastic covers toward sensor-driven and automated structures that respond dynamically to rainfall, heat, humidity, and light. Recent IoT-based shelter designs show that rain sensors, temperature sensors, and humidity sensors can trigger the automatic deployment of retractable roofs or canopies in real time, reducing the need for manual intervention and improving the timeliness of crop protection (Karanam et al., 2024). A related automated shed system also showed that fully automatic opening during rainfall and closing after rain can be achieved through Arduino- and Wi-Fi-based control, with mobile notification functions that support remote management. For cherries, this kind of responsive structure is especially relevant because conventional covers alter microclimate differently under warm and cool conditions, so the next generation of shelters should be designed to regulate rather than simply block environmental exposure (Song et al., 2026).

The most promising development pathway is to integrate shelter movement with predictive decision systems for irrigation and fruit health monitoring. Intelligent agriculture platforms already combine AI, IoT, and cloud-based interfaces to support rainfall prediction, automated control, and scalable decision-making, with the explicit goal of improving profitability and reducing labor dependence (Kaplun et al., 2024). In protected cultivation research, low-cost wireless sensor networks and fuzzy-logic controllers have also successfully managed temperature, humidity, and soil moisture through remote monitoring and automated climate decisions. Evidence from automated shed systems in other high-value crops further shows that sensor-driven opening and closing can maintain yield while lowering labor costs, which supports their future adaptation to cherry orchards exposed to increasingly erratic rainfall and heat (Sarker et al., 2025).

8.2 Integration of rain-shelter cultivation with comprehensive orchard management practices

Rain-shelter cultivation should be managed as a whole-orchard production system, because covers change light, transpiration, tree vigor, and fruit water relations in ways that interact directly with pruning, irrigation, nutrition, and crop load. A major review of covered cherry production concludes that agronomic practices such as pruning, crop load regulation, irrigation, and nutrition need to be adjusted to the specific conditions created by each protective covering system. This integration is necessary because covers can reduce total solar radiation by 50–60% and simultaneously increase shoot length and leaf area, which tends to shift trees toward stronger vegetative growth and can weaken the reproductive–vegetative balance if canopy structure is not corrected. More intensive tunnel systems therefore increasingly combine covers with dwarfing rootstocks, fruiting-wall architectures, reflective orchard floor materials, fertigation, and overhead spray delivery to optimize both canopy efficiency and fruit quality (Pino et al., 2023).

Water and crop load management are particularly important under shelters because cracking risk depends not only on fruit wetting but also on tree and fruit water status. Work on sweet cherry shows that irrigation and crop load management affect fruit water relations and susceptibility to rain-induced cracking, with deficit irrigation reducing cracked fruit at harvest compared with fully irrigated trees. Other management reviews likewise note that irrigation, fertilization, and pruning can all influence cracking, while cultivar, rootstock, and site selection remain fundamental components of a stable system (Gonçalves et al., 2023). Rain shelters can also support integrated disease management by reducing wetness duration and, in related orchard systems, lowering disease pressure enough to reduce fungicide dependence, which suggests that future cherry shelter programs should coordinate cover management with pest and disease monitoring rather than treating protection as a stand-alone structure.

8.3 Economic benefits and sustainability evaluation of rain-shelter cultivation

The economic value of rain-shelter cultivation depends strongly on regional climate risk, cultivar response, and how much of the crop’s marketable yield is normally lost to cracking or rain damage. In Southwest China, where rain and hail can cause yield losses of up to 90% in unsheltered Chinese cherry, shelter covering reduced cracking from 95% to about 4% and increased yield about fourfold, showing why investment in shelters can be highly attractive in high-risk regions. In central Chile, decision analysis similarly found that polyethylene covers could generate major benefits in southern-central production zones, while the same investment was not clearly advantageous in northern-central areas (Rojas et al., 2021). These findings indicate that future adoption should be guided by location-specific economic assessment rather than uniform recommendations.

Sustainability evaluation should expand beyond short-term yield protection to include labor, materials, waste, water use, and structural reusability. Economic analyses of new cherry orchard systems show that cover structures increase production security and yield stability, but they also generate substantial waste during use and dismantling, making improvement in environmental performance an urgent priority. The same work argues that movable structures with salvage value would improve both environmental and economic performance in shorter-cycle orchards (Ghelfi and Palmieri, 2022). Evidence from protected strawberry systems points in the same direction: rain shelters can compensate for initial costs through higher marketable yield, but the best systems are those that jointly save water and maintain profit, suggesting that future cherry evaluations should use combined indicators of profitability, input efficiency, and life-cycle sustainability rather than yield alone. Overall, the future of rain-shelter cultivation in cherries lies in intelligent automation, integrated orchard management, and region-specific economic and sustainability assessment. These three directions are the most credible pathway for converting rain shelters from a protective structure into a stable, efficient, and climate-adaptive production system.

9 Conclusions and Future Perspectives

Rain-shelter cultivation has most consistently improved cherry production stability by suppressing rain-induced cracking, the principal source of preharvest loss in many growing areas. In Southwest China, where open-field losses can reach 90%, sheltering reduced cracking from 95% to about 4% and increased yield about fourfold, showing that physical protection can convert highly unstable production into commercially viable output. Similar results across Europe indicate that coverings remain one of the most effective practical options for reducing rain damage even when cultivar-dependent cracking is not fully eliminated. A second contribution is the improvement of marketable fruit retention through lower decay, less hail and bird damage, and more stable orchard microclimate Covered systems also tend to promote larger leaf area, sustained daily photosynthesis, and improved weak-light utilization, which helps maintain tree function in rainy environments. In some regions, shelters additionally improve fruit size, soluble solids, anthocyanins, and vitamin C, although these quality gains are not universal across cultivars or covering systems.

Current research is limited first by the strong heterogeneity of shelter responses among cultivars, rootstocks, years, and climates. Some studies report major cracking reduction and stable quality, whereas others show lower firmness, lower sugars, weaker color development, or even persistent cracking under cover, especially in sensitive cultivars. Rootstock effects are also insufficiently resolved, because cracking responses under plastic covers differed sharply between Colt and F.12/1 in early work, indicating that shelter performance cannot be generalized from cover type alone. This variability makes it difficult to define universal technical standards for commercial deployment. A second limitation is that the research base still emphasizes short-term aboveground outcomes more than whole-system sustainability. Important mechanisms remain incompletely understood, including why cracking can still occur under covers without direct fruit wetting and how water transport pathways differ between open-air and protected systems. Long-term evidence on soil fertility, microbial diversity, and nutrient cycling is also sparse, even though rain shelters in pear reduced rhizosphere microbial diversity and required added nutrient and organic matter inputs to sustain production. Economic uncertainty remains another gap, because investment outcomes vary markedly by region and are highly sensitive to yield, price, and firmness penalties.

Future research should prioritize precision shelter management rather than treating rain exclusion as a fixed structure. Recent work shows that cover effects on temperature and humidity vary between warm and cool conditions, and self-ventilating systems may even reduce maximum temperature under hot weather while increasing minimum humidity, suggesting that adaptive opening, ventilation, and climate-responsive control deserve more study. Research should also integrate shelter design with pruning, crop load regulation, irrigation, and nutrition, because protective covers alter the reproductive–vegetative balance and tree water relations in ways that directly affect fruit size, firmness, and cracking susceptibility. A second priority is to combine engineering with genetic and molecular improvement. Transcriptomic studies already show that shelter covering reprograms photosynthesis, carbon fixation, and flavonoid metabolism in cherry, providing a mechanistic basis for breeding and management refinement. At the same time, stable QTLs for cracking tolerance now make marker-assisted selection a realistic complement to physical protection, which is important because tolerant cultivars remain the most economical long-term strategy. Future work should therefore evaluate shelter systems through multi-year, multi-region, and life-cycle frameworks that jointly measure yield stability, fruit quality, disease pressure, labor, material waste, and profitability. Overall, rain-shelter cultivation has become a credible tool for stabilizing cherry production under increasing climate risk, but its long-term value will depend on integrating smart cover systems, cultivar-specific management, and rigorous sustainability assessment.

Acknowledgments

I would like to thank the anonymous reviewers for their detailed review of the draft. Their specific feedback helped us correct the logical loopholes in our arguments.

Conflict of Interest Disclosure

The author affirms that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

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