Next Article in Journal
Evaluation of Tyromyces chioneus Production Using Sawdust Supplemented with Corncobs
Previous Article in Journal
Physiological Investigation of Drought Stress Tolerance of ‘W. Murcott’ Mandarin Grafted onto ‘Carrizo’, ‘Sour Orange’, and ‘Volkameriana’ Rootstocks
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Horticulturae
Volume 11
Issue 4
10.3390/horticulturae11040366
horticulturae-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

Double Grafting: A Synthesis of Applications and Future Research Horizons

by
Jialing Yu
1,2,3,
Yinglei Zhao
2,3,
Baoyu Xu
2,3,
Shiyi Tan
2,3,
Junhua Tong
4 and
Chenghao Zhang
1,2,3,*
1
College of Agriculture, Yanbian University, Jilin 133002, China
2
Equipment Institute, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
3
Key Laboratory of Agricultural Equipment for Hilly and Mountainous Areas in Southeastern China (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Hangzhou 310021, China
4
School of Mechanical Engineering, Zhejiang Sci-Tech University, Hangzhou 310021, China
*
Author to whom correspondence should be addressed.
Horticulturae 2025, 11(4), 366; https://doi.org/10.3390/horticulturae11040366
Submission received: 17 February 2025 / Revised: 7 March 2025 / Accepted: 10 March 2025 / Published: 28 March 2025
(This article belongs to the Section Developmental Physiology, Biochemistry, and Molecular Biology)
Browse Figures
Versions Notes

Abstract

:
Double grafting is an innovative horticultural technique that enables the rapid and cost-effective development of ideal plants by incorporating an interstock between the scion and rootstock. This review comprehensively examines the multifaceted impacts of double grafting on plant physiology and development. This includes how double grafting influences the plant healing process, photosynthetic efficiency, nutrient uptake and transport, phytohormone regulation, and gene expression. Furthermore, we analyze and synthesize the roles of double grafting in promoting dwarfing, regulating bud differentiation, enhancing stress tolerance, and improving overall yield and quality. By integrating insights from both fundamental research and practical applications, this review aims to provide a forward-looking perspective and a robust theoretical foundation for the global advancement of double grafting technology.

1. Introduction

Grafting, an ancient and widely adopted asexual plant propagation technique, plays a pivotal role in horticulture by enhancing productivity through improved resistance to biotic and abiotic stresses, increased yield, and optimized fruit quality [1]. In simple grafting, the scion is fused onto the rootstock, enabling the grafted plant to inherit desirable traits from the rootstock (Figure 1a). However, the practical application of simple grafting is often constrained by the challenge of selecting rootstocks that simultaneously possess multiple advantageous attributes (e.g., disease resistance, stress tolerance, and graft compatibility)—a process that is time-consuming and costly. Double grafting (also termed interstock grafting) addresses these limitations by introducing an interstock (Figure 1b). This technique not only integrates the dual advantages of both rootstock and interstock but also enhances scion-rootstock compatibility [2]. For example, transgenic sweet orange interstocks resistant to Citrus psorosis virus (CPsV) can transfer disease resistance to the scion [3]; specific interstocks in sweet orange improve graft survival rates between otherwise incompatible scion-rootstock combinations [4]; plum double grafting accelerates environmental adaptation while enhancing fruit quality [5]; apple interstocks confer dwarfing traits alongside phlorizin stress resistance [6].
Although double grafting involves more complex procedures (managing two graft junctions) and potentially higher initial costs compared to simple grafting, its long-term benefits are substantial. By shortening breeding cycles, reducing disease-related losses, and producing high-value fruits, the comprehensive returns of double grafting may surpass those of simple grafting [7]. Current research has begun to unravel the mechanisms underlying double grafting, including phytohormone regulation, gene expression networks, and metabolic reprogramming. However, optimizing interstock selection (e.g., interstock length, soil burial depth) to balance cost and efficacy remains a critical challenge for future studies. This review synthesizes molecular biological insights and field trial evidence to systematically analyze the technical advantages and application potential of double grafting, aiming to provide theoretical and practical strategies for sustainable horticulture.

2. Effects of Double Grafting on Plant Physiology

2.1. Healing Process

The healing process of grafting involves the formation of the isolation layer, callus formation, callus proliferation and bridging, and vascular tissue redifferentiation. This process ensures the normal growth and development of the grafted plant [8].
Formation of the isolation layer: During initial grafting, damaged cells from the incision undergo enzymatic oxidation to form a brown necrotic layer, termed the isolation layer. Substances such as pectins, carbohydrates, and proteins accumulate on both sides of this layer, facilitating initial cell adhesion [9].
Callus formation: Simultaneously with isolation layer development, cells from the cambium (excluding epidermal cells), phloem, cortex, xylem parenchyma, and pith initiate a dedifferentiation process. These cells proliferate into regularly arranged callus tissue [10].
Callus proliferation and bridging: The callus continues to divide, forming a continuous cambial connection—known as a callus bridge—between the scion and rootstock. This structure provides mechanical support and enables the preliminary exchange of water and nutrients [11].
Vascular tissue redifferentiation: At the margins of the newly formed callus, parenchyma cells adjacent to the cambium redifferentiate into new cambial cells. These cells generate secondary xylem inwardly and phloem outwardly; phloem reconnection typically precedes xylem reconnection [12].
The compatibility among the scion, interstock, and rootstock determines the healing state of the double-grafted plants. Among the manifestations of incompatibility during the healing period of grafting, the expansion of the graft union is the most intuitive [13]. In pear, a relatively accurate indicator of incompatibility was identified from many early indicators: the ratio of the circumference of the upper graft union to the circumference of the scion (D/E) [14], which is closer to 1, indicating better compatibility. In incompatible double-grafted citrus, internal manifestations include low chlorophyll content, high soluble sugar content in scion leaves [15], and antioxidant enzyme activities were significantly lower than in compatible grafts, suggesting that incompatibility of interstocks leads to accelerated sugar depletion or inhibition of sugar synthesis in both scions and rootstocks [16]. The above internal manifestations of double grafting incompatibility are similar to those of simple grafting. Therefore, determining whether the early incompatibility indexes of simple grafting are applicable to double grafting is one of the important directions for future research.

2.2. Photosynthetic Function

Double grafting alters the structure of scion leaves, thereby increasing the photosynthetic rate. For example, the stomatal density and pore size of citrus leaves grafted with interstocks are higher than those of leaves without interstocks. This enhances CO2 uptake by leaves and improves the photosynthetic rate. Additionally, the thickness of the lower epidermis, fenestrated tissue, and spongy tissue in citrus leaves with interstock grafting is greater than that in simple grafting (Figure 2) [17]. This further enhances the efficiency of light energy capture and conversion.
Double grafting exerts significant effects on plant photosynthesis through multiple physiological mechanisms. Double grafting with interstocks results in higher chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid contents in apple and citrus scions compared to simple grafting. This leads to enhanced light energy interception [17]. In apple, interstocks improve the overall photosynthetic rate of the plant without significant changes in scion chlorophyll content. This is evidenced by increased stomatal conductance, light saturation point, photosynthetic quantum efficiency, and photosynthetic electron transfer efficiency of the leaves, as well as facilitated leaf carbon assimilation [18]. Additionally, interstocks enhance the antioxidant capacity of the crop and reduce photodamage in photosynthesis, thereby maintaining photosynthetic stability [19].

2.3. Nutrient Uptake and Transportation

By introducing interstocks, double grafting modifies the plant’s stem structure and influences root system development. These structural changes subsequently regulate the efficiency of nutrient and water uptake, their systemic transport, and ultimately shape the overall plant phenotype. Although the exact mechanisms of regulation are not fully understood, substantial research efforts have been conducted to elucidate the underlying principles.
Double grafting directly modifies the plant’s stem structure, making the interstocks a crucial determinant of nutrient and water transport rates. For example, in peach trees, longer interstock segments and higher grafting positions increase the distance that nutrients must travel from the root to the scion. This increased distance can lead to nutrient losses and heightened metabolic demands during transport, thereby restricting scion growth potential [20]; the same phenomenon was found in mango, and the phenomenon was independent of rootstock type and vigor [21]. Some studies have further elucidated this phenomenon: Excessively long interstocks cause nitrogen stagnation, impeding upward nitrogen transport, increasing nutrient consumption, and reducing nitrogen uptake by leaves and the central stem [22]. Additionally, because the conduit structure of the interstocks differs from that of the scion and rootstock, double grafting results in thinner fiber walls, smaller conduit sizes, and reduced conduit density and lumen area compared to direct scion-to-rootstock grafting [23,24]. These changes decrease water conductivity, resulting in a significant reduction in water potential in double-grafted apples and persimmons [25,26]. Double-grafted lemons are also more susceptible to water imbalance under flooding stress [27]. Moreover, apple interstocks accumulate colloidal substances such as carbohydrates and aspartic acid, which affect cellular matrix and osmotic potentials, further contributing to decreased water potential. Understanding the transgenotypic organization of water movement in double grafting is essential for developing rational irrigation strategies and represents an important research direction in grafting studies.
Double grafting can modify the plant’s root system, thereby affecting nutrient absorption capacity. For example, the use of dwarfing interstocks can reduce the size and vigor of the root system of the rootstock [28]. These changes in root architecture further influence the rate of mineral uptake by roots, leading to differences in mineral content and distribution among apple roots from different interstocks [29]. Since interstocks often root after being buried in soil, the depth of interstock burial in double grafting also regulates plant root and scion morphology. For instance, completely burying the interstock in the soil can enhance its absorption capacity and maximize the length of new shoots and the height of the tree. Similarly, as the length of the interstock buried in the soil decreases, the plant’s growth vigor diminishes [22].
The presence of interstocks in double grafting induces changes in the root system and stem structure, which in turn alters the nutrient content in leaves and fruits. Such as, during salt stress, luffa interstock reduced Na+ accumulation in cucumber scions but increased Na+ accumulation in rootstocks, suggesting that lucerne interstock can limit Na+ transport from roots to shoots [30]. Furthermore, the effects of different interstock varieties on nutrient content also vary. For instance, differences in the contents of macroelements and minerals in leaves and fruits of plants with different apple interstocks have been observed [31]. However, a systematic explanation for these differences is still lacking.

2.4. Phytohormone Regulation

Phytohormones play a crucial role in regulating the growth of double-grafted plants. The interstock influences plant growth potential and bud differentiation by altering the levels of phytohormones such as auxin (IAA), cytokinin (CTK), including its bioactive form zeatin riboside (ZR), gibberellin (GA), and abscisic acid (ABA), and other phytohormones within the plant.
Apple interstocks reduce CTK production in the root system, thereby weakening tree growth [32]. Meanwhile, the use of dwarfing interstocks in apple and persimmon reduces the content or transport of GA in the scion. This occurs because interstocks can induce the conversion of biologically active gibberellins and their precursors in the scion to inactive forms, which inhibit stem and new shoot growth [25,33]. It is possible that phytohormone regulation by different interstock varieties may have opposing effects. To illustrate, apple interstocks can increase the (IAA + ZR + GA)/ABA ratio in the rootstock, significantly enhancing plant height and stem diameter compared to simple grafting [32]. The key phytohormone regulatory mechanisms promoting plant dwarfing differ in whether the same apple variety is utilized as a rootstock or an interstock (Figure 3) [32]. When dwarfing varieties are used as rootstocks, a reduction in the expression of the IPT3 protein, which is involved in the synthesis of CTK in the roots, has been observed. This decline has been shown to result in a decrease in CTK content within the root system, thereby directly triggering plant dwarfing [34]. When used as interstocks, the synthesis of the auxin transporter PIN1 in this stem segment is inhibited, which restricts the transport of IAA synthesized by the root system to the scion. This results in IAA accumulation in the interstock segments while reducing IAA content in the root system. Consequently, the scion receives insufficient IAA to support normal growth, resulting in dwarfing [35]. Therefore, the regulation of IAA transport by interstocks is considered a key factor in achieving plant dwarfing.
In addition to variety, the depth at which the interstock is buried in the soil is also a significant factor influencing phytohormone levels. For example, when the apple interstock was buried at a depth of 15 cm, the ratio of (IAA + GA + ZR) to ABA was significantly higher compared to other burial depths, which helped to stimulate root growth [36].

2.5. Gene Expression and Biomass Metabolism

Due to the presence of interstocks, there are notable differences in gene expression and biomass metabolism between simple and double-grafted plants. These differences affect various signaling pathways in plants, which in turn regulate plant growth and development. During the vegetative growth period, apple dwarfing interstocks enhance the expression of genes related to carbon metabolism (e.g., AATP1, GDH, PFK3) in the scion and up-regulate the expression of genes associated with nitrogen metabolism (e.g., NRT2.7, NADH, GDH) in the rootstock. This suggests that interstocks can alter the uptake and transport of carbon and nitrogen by regulating these genes, thereby influencing plant growth patterns [37], and it has been experimentally demonstrated that GA2ox is a key gene for dwarfism [25]. During the reproductive growth period, apple interstocks stimulate the expression of flowering genes (e.g., MOF1, FTIP7, AGL12, AGL24) in the scion, resulting in early flowering characteristics [37]. In the case of citrus, fruit quality can be significantly enhanced after double grafting, as interstocks up-regulate the expression of genes related to sugar and energy metabolism (e.g., FRK4, HXK1, SPS3F) in the scion after blooming, resulting in increased accumulation of sugars and organic acids in the fruit [38]. Transcriptome analysis is one of the key approaches to elucidate the mechanisms by which interstocks influence plant growth by identifying genes that affect scion morphology and rootstock development following double grafting.
The regulatory role of interstocks in plant physiology is further manifested in the modulation of enzyme activity and substance content. In double graft combinations of cold-tolerant apples, it was observed that interstock increased plant cold tolerance by boosting the activities of antioxidant enzymes such as superoxide dismutase (SOD) and peroxidase (POD), elevating proline content, and reducing the rate of superoxide anion production [39]. Melon interstocks strengthen disease resistance in grafted seedlings by reducing cellular electrolyte permeability and malondialdehyde content in cucumber scion leaves [40]. Analysis of differentially accumulated metabolites (DAMs) in pear trees with dwarfing interstocks revealed that the pathways of DAM enrichment in scions were primarily associated with vitamin B6 metabolism, whereas rootstocks were predominantly enriched in fructose and mannose metabolism [41]. These findings underscore that the regulation of carbohydrate allocation is a central physiological mechanism through which interstocks orchestrate plant growth.

3. Application of Double Grafting

Since the 1970s, the application of double grafting to achieve tree dwarfing has been reported in China. In the field of fruit trees, dwarfing apple interstocks such as M2, M7, and M6 were first introduced from Europe [42]. Subsequently, cold-resistant apple interstocks and dwarfing apple interstocks, including Jizhen 1 and Jizhen 2, were cultivated in China [43]. Additionally, interstocks for other species have been gradually developed. For example, the dwarfing pear interstocks Zhongai 1 [44] and double-grafted interstock of citrus, Satsuma mandarin, combined with melatonin treatment, confer chilling tolerance in citrus fruit during cold storage [45]. Double grafting is also utilized to conserve genetic resources, as the interstock can enter a dormant state after grafting [46]. This enables the scion to tolerate aboveground environmental stresses such as high temperature and bright light, while the rootstock resists soil-borne pathogens, drought, and salinity. At present, the primary applications of double grafting encompass controlling tree growth to achieve dwarfing, regulating flower bud differentiation, enhancing plant resistance, increasing fruit yield and improving quality, and improving the compatibility and performance of rootstock-scion combinations that were originally of low compatibility in simple grafting (Table 1).

3.1. Dwarfing

Based on the mechanism of double grafting’s impact on plants, the dwarfing effect of interstocks can be applied to practical production. Dwarfed fruit trees have a shorter stature, facilitating pruning, harvesting, and pest control, thereby reducing management costs.
Dwarfing interstocks can significantly reduce tree height, resulting in a more compact canopy, which is suitable for high-density planting. Many studies have shown that dwarfing interstocks contribute to restricting plant height, crown size, and tree volume; interstocks can continue to dwarf the tree to 80% of the height of a simple graft, or even more [65,66]. Based on the mechanism of the interstock effect on plant nutrient uptake and transport, the dwarfing effect increased with longer rootstock segments, although the relationship was not linear. About 20–30 cm interstock segment was found to be the most effective for dwarfing in apple and persimmon studies; the dwarfing effect was improved by about 20% and 17% compared to 10 cm and 15 cm [22,67]. Similarly to simple grafting, the degree of scion dwarfing in double grafting also varies depending on the ploidy of the polyploid rootstocks. For example, in loquat double grafting, the use of triploid interstocks resulted in a more significant dwarfing effect compared to diploid interstocks or no interstocks [68]. Currently, the specific mechanism underlying scion growth differences caused by interstocks of different ploidy levels remains unclear. However, it may be explained by differences in rootstock compatibility and phytohormone levels among rootstocks of varying ploidy.
In practice, the dwarfing effect of double grafting with interstocks is influenced by multiple factors, such as graft compatibility, depth of interstock burial, and environmental conditions. Therefore, it is essential to select appropriate double grafting combinations based on local conditions to enhance the dwarfing effect and improve economic yield.

3.2. Regulation of Flower Bud Differentiation

Double grafting can regulate flower bud differentiation in plants. For example, interstocks in pistachio trees can delay flowering by 10 days compared to simple grafting, while apple interstocks can promote flower bud differentiation [37,69]. In production, interstocks can be selected to promote or delay flower bud differentiation based on market demand. The length and position of the interstock also affect flower bud differentiation. Higher grafting positions or longer peach interstocks can shorten bud length, increase bud numbers, and delay flowering, a strategy often used to prevent potential damage from late spring frosts [20].

3.3. Enhancing Stress Tolerance

Double grafting enhances plant resistance to biotic and abiotic stresses. For example, Interstocks enhance plant drought and cold resistance by reducing the electrolyte leakage rate of scion cells and increasing the efficiency of plant nitrogen uptake and utilization [29]. In the rhizosphere and endophytic bacterial communities of double grafting apple, the relative abundance of beneficial bacteria (such as Phenylobacterium and Kribbella) increased significantly, promoting plant growth and improving disease resistance [70]. Cucumber grafted seedlings using melon interstocks were significantly less diseased than autochthonous and simple-grafted seedlings in experiments inoculated with powdery mildew sources, disease incidence was reduced by 30% and 15%, respectively [40]. The use of resistant interstocks in pear increased plant resistance to pear woodlouse [71]. Similarly, the grafting of ‘Garrigues’ apricots as an interstock significantly reduces the symptoms of sharka (Plum pox virus, PPV) infection and virus accumulation in peach trees and even prevents the virus completely after grafting [72]. In the future, the mechanisms by which interstocks improve disease resistance can be further explored, and new combinations of disease-resistant rootstocks can be developed.

3.4. Enhancement of Yield and Quality

Double grafting with interstocks can significantly enhance fruit quality in terms of fruit appearance, aroma, and flavor. For example, the content of aromatic compounds in apples after double grafting can be twice as high as that in apples after simple grafting. Additionally, this method can increase the levels of anthocyanins and phenolic compounds in the fruit skin, boost the content of soluble solids in the fruit flesh, and lead to higher yields [73,74]. In a peach grafting study, the fruit load of double-grafted plants was even increased by about 50% compared to the simple-grafted plants [20]. Moreover, the interstock plays a crucial role in modulating the activities of enzymes related to ester and aldehyde synthesis during kiwifruit ripening, thereby significantly boosting the content of volatile metabolites in the fruit [58]; this results in a more pronounced aroma compared to fruit from simple-grafted plants. The depth of interstock burial in the soil also affects fruit quality. When the depth of apple dwarfing interstock burial is within an optimal range (about 15 cm), fruit shape, coloration, and ripening are improved [75]. In the case of cucumber grafting, melon interstocks dramatically enhance the fruit shape index of cucumber, and the contents of characteristic flavor substances (e.g., nonanal, (2E)-nonenal, tridecanal) in cucumber fruit are increased compared to those of simple grafting. Additionally, in the fruits of cucumbers that have undergone double grafting, new flavor compounds (e.g., tetradecanal, hexadecanal, maple balsam) can be detected, which are characteristic of melons [61]. Therefore, studying new double grafting combinations is beneficial for obtaining better quality fruit and vegetable products.

3.5. As a Mediator of Non-Compatible Grafting

Interstocks can facilitate the successful grafting of otherwise low-compatibility rootstock-scion, resolving both localized and translocated incompatibilities. Localized incompatibility occurs at the junction between the scion and rootstock, where the cells of the scion fail to integrate and differentiate properly due to physiological, biochemical, and genetic disparities. Translocated incompatibility is a more complex type, involving specific signaling molecules produced by either the scion or the rootstock that are not correctly recognized and responded to by the other, thereby affecting the growth and development of the entire graft [76]. In citrus grafting studies, the use of the closely related sweet orange as an interstock allowed the successful grafting of low-compatibility lemon rootstock to sweet orange scion without later manifestations of incompatibility. This role facilitates the integration of plant tissues and enhances the overall health and vigor of the grafted plant [77]. However, the mechanisms by which interstocks modulate the molecular communication between scion and rootstock to enhance compatibility remain poorly understood.

3.6. Microinterstocks

Micrografting is a plant propagation technique that allows the production of large numbers of virus-free grafted seedlings in a short period of time. One study has attempted to produce cherry-grafted seedlings with microinterstock using parafilm as a wrapping material around the grafted part, but the survival rate was extremely low, only 10% [78]. The potential for future applications of micrografting technology is substantial, but key challenges such as the low survival rate of double grafting, optimization of wrapping materials, and control of environmental conditions need to be overcome to achieve its wide application in the efficient propagation of virus-free seedlings.

4. Research Directions for Subsequent Studies on Double Grafting

In this paper, we reviewed 424 Chinese and English documents published from January 2020 to December 2024, focusing on the themes of “interstock”. As shown in Figure 4a, in the last five years, apple was the most widely studied variety, accounting for 63% (267 papers) of the reviewed literature. This was followed by citrus with 8% (36 papers) and pear with 5% (21 papers). Therefore, apple, citrus, and pear are considered to be the main experimental materials for research related to interstocks. As shown in Figure 4b, when the literature was categorized according to research fields, dwarfing interstocks were considered to be a research hotspot, followed by fruit yield and quality.
The research species in double grafting are more concentrated, while the research directions for the physiological impacts of interstocks vary. The maturity of technologies such as histological analysis, high-throughput sequencing technologies, and CRISPR/Cas9 genome editing has provided more efficient theoretical and technical support for research on double grafting. Future research on double grafting should focus on the following aspects:
Firstly, currently, research on and the application of double grafting is focused on dwarfing and improving the quality, yield, and resistance of fruit trees. It is worth noting that interstocks are an effective method of resolving rootstock-scion incompatibility and thus serve a dual purpose: mediating the compatibility of previously incompatible rootstock-scion while producing fruit with novel flavors. Given that market demands will become more diverse in the future, this approach can be utilized to develop grafting combinations while systematically evaluating their performance to predict a number of metrics, including graft survival, disease resistance, yield stability, and fruit quality. Double grafting also provides an improved pathway for ornamental plants. In roses, the use of interstocks is already a precedent [79], so in the future we could consider using a disease-resistant variety as the base rootstock, then grafting a dwarfing interstock, and ultimately connecting it to a scion with a rare flower color, which would simultaneously address the problems of collapse, disease, and varietal degradation that have traditionally characterized the cultivation, as well as controlling the height of the plant, resulting in a more compact plant shape. This way is especially suitable for ornamental plants with high requirements for plant shape, stress resistance, and ornamental properties.
Secondly, the factors affecting the growth of double-grafted plants and their underlying mechanisms remain a critical area of investigation. In the future, in-depth research should focus on elucidating the mechanisms by which double grafting affects phytohormone metabolism and gene expression, as well as how bioregulator applications influence the physiology of double-grafted plants. Additionally, the effects of environmental factors (e.g., light, temperature, water, and soil conditions) on the physiology of double-grafted plants need further investigation. In particular, studies should examine how interstocks enhance plant adaptation to extreme environmental conditions by regulating the activity of antioxidant enzymes and the accumulation of osmoregulatory substances.
Thirdly, the gene expression and signaling mechanisms in double grafting are an area of interest. The biological mechanisms by which interstocks overcome graft incompatibility, such as the mechanisms of material transport and signaling between the rootstock and scion, still warrant deeper exploration. To this end, we should fully utilize modern molecular biology techniques, such as transcriptomics, metabolomics, and proteomics, to systematically analyze the molecular communication networks at the grafting interface. This will provide new insights into the physiological and biochemical mechanisms of double grafting.
The influence of interstocks on plant growth and development is mediated by a multifaceted network of mechanisms. Anatomical modifications induced by the interstocks impact the efficiency of water and inorganic ion translocation, resulting in diminished tree vigor. Furthermore, interstocks modulate photosynthetic processes and nutrient allocation, affecting carbohydrate accumulation, partitioning, and the regulation of floral initiation. Phytohormonal regulation is also critical; interstocks inhibit longitudinal growth by modulating phytohormone metabolism, specifically reducing the levels of gibberellins and cytokinins. Genetic studies have implicated specific genes in the dwarfing phenotype conferred by interstocks, with reduced expression of the PIN gene family being correlated with dwarfing effects. In summary, interstocks regulate growth in grafted plants through the synergistic integration of anatomical, photosynthetic, phytohormonal, and genetic mechanisms. Further studies on the mechanism of action of interstocks will help to further expand the research and application of double grafting in horticultural crops.

Author Contributions

Conceptualization, J.Y.; formal analysis, Y.Z.; investigation, S.T. and B.X.; resources, J.T.; project administration, C.Z. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Zhejiang Provincial Department of Agriculture and Rural Affairs, Development of automatic grafting machine and ripening of tomato seedlings-Agronomic technology research on automatic grafting of tomato seedlings, grant number 10413030224KB0901F. Zhejiang Province “Three Rural Nine Parties” Science and Technology Collaboration Program, grant number 2024SNJF013.

Data Availability Statement

No new data were created or analyzed in this study.

Acknowledgments

The authors would like to thank all the participants for their comments and help with this project.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Goldschmidt, E.E. Plant Grafting: New Mechanisms, Evolutionary Implications. Front. Plant Sci. 2014, 5, 727. [Google Scholar] [CrossRef] [PubMed]
  2. Miodragović, M.; Magazin, N.; Keserović, Z.; Milić, B.; Popović, B.; Blagojević, B.; Kalajdžić, J. The Early Performance and Fruit Properties of Apricot Cultivars Grafted on Prunus spinosa L. Interstock. Sci. Hortic. 2019, 250, 199–206. [Google Scholar] [CrossRef]
  3. De Francesco, A.; Simeone, M.; Gómez, C.; Costa, N.; García, M.L. Transgenic Sweet Orange Expressing Hairpin CP-mRNA in the Interstock Confers Tolerance to Citrus Psorosis Virus in the Non-Transgenic Scion. Transgenic. Res. 2020, 29, 215–228. [Google Scholar] [CrossRef]
  4. Guilherme, D.D.O.; Marinho, C.S.; Biazatt, M.A.; Campos, G.S.; Bremenkamp, C.A. Produção de Mudas de Laranjeira Pêra Por Meio Do Método de Interenxertia. Cienc. Rural. 2014, 44, 414–417. [Google Scholar] [CrossRef]
  5. Popara, G.; Magazin, N.; Keserović, Z.; Milić, B.; Milović, M.; Kalajdžić, J.; Manojlović, M. Rootstock and Interstock Effects on Plum Cv. ‘Čačanska Lepotica’ Young Tree Performance and Fruit Quality Traits. Erwerbs-Obstbau 2020, 62, 421–428. [Google Scholar] [CrossRef]
  6. Sun, W.; Cao, Y.; Du, P.; Li, Z.; Xu, Z.; Zhou, S.; Li, Z.; Zhang, X.; Liang, B. Evaluation of Phlorizin Stress Resistance and Mineral Nutrient Utilization Efficiency in Apple Seedlings with Different Dwarfing Interstocks. Sci. Hortic. 2025, 340, 113947. [Google Scholar] [CrossRef]
  7. Hayat, F.; Li, J.; Iqbal, S.; Peng, Y.; Hong, L.; Balal, R.M.; Khan, M.N.; Nawaz, M.A.; Khan, U.; Farhan, M.A.; et al. A Mini Review of Citrus Rootstocks and Their Role in High-Density Orchards. Plants 2022, 11, 2876. [Google Scholar] [CrossRef]
  8. Kirca, L.; Karadeniz, T. Histological Investigation of the Compatibility of Prunus spinosa as Interstock with Almond Cultivars. Appl. Fruit Sci. 2024, 66, 1305–1316. [Google Scholar] [CrossRef]
  9. Serivichyaswat, P.T.; Kareem, A.; Feng, M.; Melnyk, C.W. Auxin Signaling in the Cambium Promotes Tissue Adhesion and Vascular Formation during Arabidopsis Graft Healing. Plant Physiol. 2024, 196, 754–762. [Google Scholar] [CrossRef]
  10. Wang, L.; Liao, Y.; Liu, J.; Zhao, T.; Jia, L.; Chen, Z. Advances in Understanding the Graft Healing Mechanism: A Review of Factors and Regulatory Pathways. Hortic. Res. 2024, 11, uhae175. [Google Scholar] [CrossRef]
  11. Feng, M.; Augstein, F.; Kareem, A.; Melnyk, C.W. Plant Grafting: Molecular Mechanisms and Applications. Mol. Plant 2024, 17, 75–91. [Google Scholar] [CrossRef] [PubMed]
  12. Nanda, A.K.; Melnyk, C.W. The Role of Plant Hormones during Grafting. J. Plant. Res. 2018, 131, 49–58. [Google Scholar] [CrossRef] [PubMed]
  13. Tedesco, S.; Fevereiro, P.; Kragler, F.; Pina, A. Plant Grafting and Graft Incompatibility: A Review from the Grapevine Perspective. Sci. Hortic. 2022, 299, 111019. [Google Scholar] [CrossRef]
  14. Li, H.; Li, D.; Wang, R.; Ma, C. Effects of different dwarfing interstocks on Whangkumbae pear growth and correlation analysis of graft-compatibility. Acta Agric. Zhejiangensis 2022, 34, 1175–1182. [Google Scholar] [CrossRef]
  15. Wang, T.; Deng, L.; Huang, S.; Xiong, B.; Ihtisham, M.; Zheng, Z.; Zheng, W.; Qin, Z.; Zhang, M.; Sun, G.; et al. Genetic Relationship, SPAD Reading, and Soluble Sugar Content as Indices for Evaluating the Graft Compatibility of Citrus Interstocks. Biology 2022, 11, 1639. [Google Scholar] [CrossRef]
  16. Wang, T.; Jin, Z.; Yuan, Y.; Deng, L.; Sun, G.; He, S.; Liao, L.; Wang, J.; Xiong, B.; Wang, Z. Interstock-Mediated Graft Incompatibility: Insights into Photosynthetic Pigments, Carbohydrates, Antioxidant Defense Systems, and Hormones Response Mechanisms in Citrus. Plants 2025, 14, 522. [Google Scholar] [CrossRef]
  17. Rong, Y.; Liao, L.; Li, S.; Wei, W.; Bi, X.; Sun, G.; He, S.; Wang, Z. Comparative Transcriptomic and Physiological Analyses Reveal Key Factors for Interstocks to Improve Grafted Seedling Growth in Tangor. Int. J. Mol. Sci. 2023, 24, 6533. [Google Scholar] [CrossRef]
  18. Zhou, Y.Q.; Qin, S.J.; Ma, X.X.; Zhang, J.E.; Zhou, P.; Sun, M.; Wang, B.S.; Zhou, H.F.; Lyu, D.G. Effect of Interstocks on the Photosynthetic Characteristics and Carbon Distribution of Young Apple Trees during the Vigorous Growth Period of Shoots. Europ. J. Hort. Sci. 2015, 80, 296–305. [Google Scholar] [CrossRef]
  19. Fayek, M.A.; Rashedy, A.A.; Ali, A.E.M. Alleviating the Adverse Effects of Deficit Irrigation in Flame Seedless Grapevine via Paulsen Interstock. Rev. Bras. Frutic. 2022, 44, e-839. [Google Scholar] [CrossRef]
  20. Calderón, F.J.; Weibel, A.M.; Trentacoste, E.R. Effects of Different Interstock Length on Vegetative Growth and Flowering in Peach Cv. Pavie Catherine. Sci. Hortic. 2021, 285, 110174. [Google Scholar] [CrossRef]
  21. Casierra–Posada, F.; Guzmán, J.A. Effect of Rootstock and Interstock on Mthe Fruit Quality of Mango (Mangifera Indica L.). Agron. Colomb. 2009, 27, 367–374. [Google Scholar]
  22. Zhou, S.; Shen, Z.; Yin, B.; Liang, B.; Li, Z.; Zhang, X.; Xu, J. Effects of Dwarfing Interstock Length on the Growth and Fruit of Apple Tree. Horticulturae 2023, 9, 40. [Google Scholar] [CrossRef]
  23. Li, C.; Yang, T.; Gao, J.; Wang, Q.; Cai, H.; Du, X.; Wang, S.; Gong, G.; Wang, X.; Zhang, Y.; et al. Dwarfing Mechanism of Apple Dwarf Rootstock: Research Progress. Chin. Agric. Sci. Bull. 2017, 33, 86. [Google Scholar] [CrossRef]
  24. Doley, D. Effects of Rootstocks and Interstock on Cell Dimensions in Scion Stems of Apple (Malus pumila Mill). New Phytol. 1974, 73, 173–194. [Google Scholar] [CrossRef]
  25. Shen, Y.; Zhuang, W.; Tu, X.; Gao, Z.; Xiong, A.; Yu, X.; Li, X.; Li, F.; Qu, S. Transcriptomic Analysis of Interstock-Induced Dwarfism in Sweet Persimmon (Diospyros kaki Thunb.). Hortic. Res. 2019, 6, 51. [Google Scholar] [CrossRef]
  26. Zhang, X.; Yang, W.; Tahir, M.M.; Chen, X.; Saudreau, M.; Zhang, D.; Costes, E. Contributions of Leaf Distribution and Leaf Functions to Photosynthesis and Water-Use Efficiency from Leaf to Canopy in Apple: A Comparison of Interstocks and Cultivars. Front. Plant Sci. 2023, 14, 1117051. [Google Scholar] [CrossRef]
  27. Gimeno, V.; Syvertsen, J.P.; Simon, I.; Martinez, V.; Camara-Zapata, J.M.; Nieves, M.; Garcia-Sanchez, F. Interstock of ‘Valencia’ Orange Affects the Flooding Tolerance in ‘Verna’ Lemon Trees. HortScience 2012, 47, 403–409. [Google Scholar] [CrossRef]
  28. Ma, L.; Hou, C.W.; Zhang, X.Z.; Li, H.L.; Han, D.G.; Wang, Y.; Han, Z.H. Seasonal Growth and Spatial Distribution of Apple Tree Roots on Different Rootstocks or Interstems. J. Am. Soc. Hortic. Sci. 2013, 138, 79–87. [Google Scholar] [CrossRef]
  29. Zapata, J.M.C.; Cerdá, A.; Nieves, M. Interstock-Induced Mechanism of Increased Growth and Salt Resistance of Orange (Citrus Sinensis) Trees. Tree Physiol. 2004, 24, 1109–1117. [Google Scholar] [CrossRef]
  30. Guo, Z.; Qin, Y.; Lv, J.; Wang, X.; Dong, H.; Dong, X.; Zhang, T.; Du, N.; Piao, F. Luffa Rootstock Enhances Salt Tolerance and Improves Yield and Quality of Grafted Cucumber Plants by Reducing Sodium Transport to the Shoot. Environ. Pollut. 2023, 316, 120521. [Google Scholar] [CrossRef]
  31. Ji, J.; He, X.; Liu, H.; Li, Z.; Zhou, S.; Zhang, X.; Xu, J.; Liang, B. Influence of Dwarfing Interstock on the Tolerance and Nutrient Utilization Efficiency of Apple Trees under Drought Stress. Sci. Hortic. 2023, 315, 111984. [Google Scholar] [CrossRef]
  32. Li, H.L.; Zhang, H.; Yu, C.; Ma, L.; Wang, Y.; Zhang, X.Z.; Han, Z.H. Possible Roles of Auxin and Zeatin for Initiating the Dwarfing Effect of M9 Used as Apple Rootstock or Interstock. Acta. Physiol. Plant. 2012, 34, 235–244. [Google Scholar] [CrossRef]
  33. Li, Y.; Ma, Z.; Li, Y.; Li, W.; Sun, L.; Xu, J.; Mao, J.; Chen, B. Modification of Fruit Quality and Leaf Mineral Composition of ‘Nagafu No.2’ Apple Grafted onto Four Dwarfing Interstocks. J. Plant. Growth Regul. 2023, 42, 7240–7256. [Google Scholar] [CrossRef]
  34. Feng, Y.; Zhang, X.; Wu, T.; Xu, X.; Han, Z.; Wang, Y. Methylation Effect on IPT5b Gene Expression Determines Cytokinin Biosynthesis in Apple Rootstock. Biochem. Biophys. Res. Commun. 2017, 482, 604–609. [Google Scholar] [CrossRef] [PubMed]
  35. Verma, P.; Sharma, N.C.; Sharma, D.P.; Kumar, P.; Chand, K.; Thakur, H. Dwarfism Mechanism in Malus Clonal Rootstocks. Planta 2024, 260, 133. [Google Scholar] [CrossRef]
  36. Ren, X.F.; Li, B.Z.; Zhang, L.S.; Han, M.Y.; Li, X.W. Effects of Planting Depth of Apple Dwarfing Rootstock on Root Growth, Hormone Content, Fruit Yields and Quality. Acta Hortic. Sin. 2013, 40, 2127. [Google Scholar]
  37. Li, Q.; Gao, Y.; Wang, K.; Feng, J.; Sun, S.; Lu, X.; Liu, Z.; Zhao, D.; Li, L.; Wang, D. Transcriptome Analysis of the Effects of Grafting Interstocks on Apple Rootstocks and Scions. Int. J. Mol. Sci. 2023, 24, 807. [Google Scholar] [CrossRef]
  38. Liao, L.; Li, Y.; Bi, X.; Xiong, B.; Wang, X.; Deng, H.; Zhang, M.; Sun, G.; Jin, Z.; Huang, Z.; et al. Transcriptome Analysis of Harumi Tangor Fruits: Insights into Interstock-Mediated Fruit Quality. Front. Plant Sci. 2022, 13, 995913. [Google Scholar] [CrossRef]
  39. Jing, J.; Liu, M.; Yin, B.; Liang, B.; Li, Z.; Zhang, X.; Xu, J.; Zhou, S. Effects of 10 Dwarfing Interstocks on Cold Resistance of ‘Tianhong 2’ Apple. Horticulturae 2023, 9, 827. [Google Scholar] [CrossRef]
  40. Wang, L.; Guan, M.; Zhong, D.; Liu, S. Effects of Interstock Grafting on Cucumber Resistance to Powdery Mildew. J. Shandong Agric. Univ. (Nat. Sci. Ed.) 2020, 51, 206–211. [Google Scholar] [CrossRef]
  41. Cui, Z.; Zhang, H.; Galarneau, E.R.-A.; Yang, Y.; Li, D.; Song, J.; Ma, C.; Zhang, S.; Wang, R. Metabolome Analysis Reveals Important Compounds Related to Dwarfing Effect of Interstock on Scion in Pear. Ann. Appl. Biol. 2021, 179, 108–122. [Google Scholar] [CrossRef]
  42. Li, W.; Chu, C.; Li, H.; Zhang, H.; Sun, H.; Wang, S.; Wang, Z.; Li, Y.; Foster, T.M.; López-Girona, E.; et al. Near-Gapless and Haplotype-Resolved Apple Genomes Provide Insights into the Genetic Basis of Rootstock-Induced Dwarfing. Nat. Genet. 2024, 56, 505–516. [Google Scholar] [CrossRef] [PubMed]
  43. Liang, B.; Shi, Y.; Yin, B.; Zhou, S.; Li, Z.; Zhang, X.; Xu, J. Effect of Different Dwarfing Interstocks on the Vegetative Growth and Nitrogen Utilization Efficiency of Apple Trees under Low-Nitrate and Drought Stress. Sci. Hortic. 2022, 305, 111369. [Google Scholar] [CrossRef]
  44. Ou, C.; Wang, F.; Wang, J.; Li, S.; Zhang, Y.; Fang, M.; Ma, L.; Zhao, Y.; Jiang, S. A de Novo Genome Assembly of the Dwarfing Pear Rootstock Zhongai 1. Sci. Data 2019, 6, 281. [Google Scholar] [CrossRef]
  45. Liao, L.; Li, J.; Lan, X.; Li, Y.; Li, Y.; Huang, Z.; Jin, Z.; Yang, Y.; Wang, X.; Zhang, M.; et al. Exogenous Melatonin and Interstock Treatments Confer Chilling Tolerance in Citrus Fruit during Cold Storage. Sci. Hortic. 2024, 327, 112802. [Google Scholar] [CrossRef]
  46. Nee, C. 039 Interstock Preservation of Plant Germplasm. HortScience 1994, 29, 433d–433. [Google Scholar] [CrossRef]
  47. Zhao, D.; Yuan, J.; Xu, K.; Cheng, C.; Li, H. Selection of Morphological, Physiological and Biochemical Indices: Evaluating Dwarfing Apple Interstocks in Cold Climate Zones. N. Z. J. Crop Hortic. Sci. 2016, 44, 291–311. [Google Scholar] [CrossRef]
  48. Di Vaio, C.; Cirillo, C.; Buccheri, M.; Limongelli, F. Effect of Interstock (M.9 and M.27) on Vegetative Growth and Yield of Apple Trees (Cv “Annurca”). Sci. Hortic. 2009, 119, 270–274. [Google Scholar] [CrossRef]
  49. Yuan, J.-C.; Cheng, C.-G.; Zhao, D.-Y.; Liu, S.-T.; Li, E.-M. Effects of different interstocks on the growth, yield, and fruit quality of Hanfu apple. Ying Yong Sheng Tai Xue Bao 2021, 32, 3145–3151. [Google Scholar] [CrossRef]
  50. Oliveira, J.A.A.; Bruckner, C.H.; Silva, D.F.P.D.; Santos, C.E.M.D.; Soares, W.D.S.; Nunes, L.V. Performance of Interstocks in the Plant Development and Fruit Quality of Plum Trees. Acta Sci. Agron. 2019, 41, 39928. [Google Scholar] [CrossRef]
  51. Edstrom, J.P.; Connell, J.H.; Micke, W.C.; Yeager, J.T. ‘Marianna 2624’ Plum as a Rootstock for Almond. Horttech 1999, 9, 127. [Google Scholar] [CrossRef]
  52. Yilmaz, B.; Kamiloğlu, M.; Çimen, B.; Incesu, M.; Yesiloglu, T.; Tuzcu, O. Effects of different interstock lengths on the yield, fruit quality and tree size of Kütdiken lemon trees in Turkey. J. Glob. Agric. Ecol. 2015, 3, 91–96. [Google Scholar]
  53. Kamiloğlu, M.; Yeşiloğlu, T. Effect of Interstocks In Photosynthesis and Growth Rates for ‘Navelina’ Orange And ‘Kütdiken’ Lemon. Türk Tarım Doğa Bilimleri Dergisi 2014, 1, 939–946. [Google Scholar]
  54. Shokrollah, H.; Lee Abdullah, T.; Sijam, K.; Akmar Abdullah, S.N. Potential Use of Selected Citrus Rootstocks and Interstocks against HLB Disease in Malaysia. Crop Prot. 2011, 30, 521–525. [Google Scholar] [CrossRef]
  55. Gil-Izquierdo, A.; Riquelme, M.T.; Porras, I.; Ferreres, F. Effect of the Rootstock and Interstock Grafted in Lemon Tree (Citrus limon (L.) Burm.) on the Flavonoid Content of Lemon Juice. J. Agric. Food Chem. 2004, 52, 324–331. [Google Scholar] [CrossRef]
  56. Liang, Z.; Wang, Q.; Sun, M.; Du, R.; Jin, W.; Liu, S. Transcriptome and Metabolome Profiling Reveal the Effects of Hormones on Current-Year Shoot Growth in Chinese ‘Cuiguan’ Pear Grafted onto Vigorous Rootstock ‘Duli’ and Dwarf Rootstock ‘Quince A’. BMC Plant. Biol. 2024, 24, 169. [Google Scholar] [CrossRef]
  57. Guo, L.; Chen, P.; Sun, Y.; Liu, S.; Li, F.; Chen, Y.; Li, X. Effects of Different Interstocks on Tree Growth and Fruit Quality of Jinqiushatangju. Acta Agric. Univ. Jiangxiensis 2021, 43, 1278–1286. [Google Scholar] [CrossRef]
  58. Zhang, H.; Li, X.; Li, Y.; Chen, Z.; Yue, Y.; Zhai, J.; Zhao, Z.; Ji, X. Effects of Different Rootstocks on Fruit Quality of Jianxiang Kiwifruit. South China Fruits 2024, 53, 161–168+175. [Google Scholar] [CrossRef]
  59. Singh, N.P.; Srivastava, R.P. A New Approach towards Double Grafting in Mango. Curr. Sci. 1980, 1, 678–679. [Google Scholar]
  60. Fayek, M.A.; Ali, A.E.M.; Rashedy, A.A. Physiological and Chemical Performance of the Flame Seedless Grapevine Cultivar in the Presence of Paulsen 1103 as the Interstock. Ciênc. Agrotec. 2022, 46, e021621. [Google Scholar] [CrossRef]
  61. Wang, L.; Dong, Y.; Sun, X.; Liu, S. Effects of different grafting methods and different interstock graftings on fruit quality and volatile compounds in cucumber. Plant Physiol. J. 2019, 55, 867–874. [Google Scholar] [CrossRef]
  62. Miguel, A.; Marsal, J.I.; Maroto Borrego, J.V.; López-Galarza, S.; San Bautista, A.; Bono, M. Evaluación del injerto intermedio como solución a los problemas de afinidad del melón piel de sapo injertadoJornadas del grupo de horticultura. Fund. Rural. Valencia 2008, 50, 237–240. [Google Scholar]
  63. Miguel, A.; Marsal, J.I.; San Bautista, A.; López-Galarza, S.; Pascual, B.; Maroto, J.V. Double Grafting As A Method To Solve Affinity Problems In “Piel De Sapo” Melon Cultivars. Acta Hortic. 2011, 898, 287–290. [Google Scholar] [CrossRef]
  64. German, M.A.; Dai, N.; Matsevitz, T.; Hanael, R.; Petreikov, M.; Bernstein, N.; Ioffe, M.; Shahak, Y.; Schaffer, A.A.; Granot, D. Suppression of Fructokinase Encoded by LeFRK2 in Tomato Stem Inhibits Growth and Causes Wilting of Young Leaves. Plant J. 2003, 34, 837–846. [Google Scholar] [CrossRef] [PubMed]
  65. Hayat, F.; Iqbal, S.; Coulibaly, D.; Razzaq, M.K.; Nawaz, M.A.; Jiang, W.; Shi, T.; Gao, Z.; Hayat, F.; Iqbal, S.; et al. An Insight into Dwarfing Mechanism: Contribution of Scion-Rootstock Interactions toward Fruit Crop Improvement. Fruit Res. 2021, 1, 1–11. [Google Scholar] [CrossRef]
  66. Karlıdağ, H.; Aslantaş, R.; Eşitken, A. Effects of Interstock (M9) Length Grafted onto MM106 Rootstock on Sylleptic Shoot Formation, Growth and Yield in Some Apple Cultivars. J. Agric. Sci. 2014, 4, 70–73. [Google Scholar]
  67. Dong, Y.; Ye, X.; Xiong, A.; Zhu, N.; Jiang, L.; Qu, S. The Regulatory Role of Gibberellin Related Genes DKGA2ox1 and MIR171f_3 in Persimmon Dwarfism. Plant Sci. 2021, 310, 110958. [Google Scholar] [CrossRef]
  68. Wu, T.; He, H.; Dang, J.; Li, X.; He, Q.; Guo, Q.; Liang, G.; Huang, X.; Peng, W. Seedling growth and photosynthetic efficiency of loquat plants with different ploidy of “Hua Bai 1” as interstock. South China Fruits 2023, 52, 92–96. [Google Scholar] [CrossRef]
  69. Mahmoudi Meimand, M.J.; Shamshiri, M.H. Effects of Rootstock and Interstock on Pollen Traits and Flowering Synchronization in Pistachio (Pistacia vera L.). Erwerbs-Obstbau 2019, 61, 267–271. [Google Scholar] [CrossRef]
  70. Cao, Y.; Li, Z.; Du, P.; Ji, J.; Sun, W.; Xu, J.; Liang, B. Effects of Different Dwarfing Interstocks on the Rhizosphere, Endophytic Bacteria, and Drought Resistance of Apple Trees. Microbiol. Res. 2024, 283, 127690. [Google Scholar] [CrossRef]
  71. Shaltiel-Harpaz, L.; Gerchman, Y.; Ibdah, M.; Kedoshim, R.; Rachmany, D.; Hatib, K.; Bar-Ya’akov, I.; Soroker, V.; Holland, D. Grafting on Resistant Interstocks Reduces Scion Susceptibility to Pear Psylla, Cacopsylla Bidens. Pest Manag. Sci. 2018, 74, 617–626. [Google Scholar] [CrossRef] [PubMed]
  72. Rubio, M.; Martínez-García, P.J.; Martínez-Gómez, P.; Dicenta, F. Plum Pox Virus (Sharka) Resistance in Peach by Grafting ‘Garrigues’ Almond as Interstock. Sci. Hortic. 2024, 338, 113749. [Google Scholar] [CrossRef]
  73. Marcon, J.L.; Kretzschmar, A.A.; Hipólito, J.d.S.; Rufato, A.D.R.; Rufato, L.; Wurz, D.A. Increasing the Length of EM-9 Interstock Enhances Production Efficiency in Imperial Gala Apples. Rev. Ceres 2019, 66, 178–183. [Google Scholar] [CrossRef]
  74. Lu, X.; Gao, Y.; Wang, K.; Sun, S.; Liu, Z.; Yan, P.; Feng, J.; Li, Q.; Li, L.; Wang, D. Dwarf Interstocks Improve Aroma Quality of ‘Huahong’ Apple (Malus × Domestica). Agriculture 2022, 12, 1710. [Google Scholar] [CrossRef]
  75. Li, B.; Wang, J.; Ren, X.; Bao, L.; Zhang, L.; Zhang, L.; Han, M.; Zhang, D. Root Growth, Yield and Fruit Quality of “Red Fuji” Apple Trees in Relation to Planting Depth of Dwarfing Interstock on the Loess Plateau. Eur. J. Hortic. Sci. 2015, 80, 109–116. [Google Scholar] [CrossRef]
  76. Kumar, A.; Kumar, A.; Kumar, R.; Wamiq, M.; Gautam, P.; Gangwar, V. Graft Incompatibility Problem in Fruit Propagation and Scion-Stock Relationship; AkiNik Publications: Delhi, India, 2023; ISBN 978-93-5570-527-3. [Google Scholar]
  77. Girardi, E.A.; Mourão Filho, F.D.A.A. Production of Interstocked “Pera” Sweet Orange Nursey Trees on “Volkamer” Lemon and “Swingle” Citrumelo Rootstocks. Sci. Agric. 2006, 63, 5–10. [Google Scholar] [CrossRef]
  78. Exadaktylou, E.; Thomidis, T.; Grout, B.; Tsipouridis, C. Methods to Propagate the Cherry Rootstock Gisela 5 by Using Root Cuttings and Application of Micrografting. Adv. Hortic. Sci. 2007, 21, 51–54. [Google Scholar]
  79. Zlesak, D.C. Rose. In Flower Breeding and Genetics: Issues, Challenges and Opportunities for the 21st Century; Anderson, N.O., Ed.; Springer: Dordrecht, The Netherlands, 2006; pp. 695–740. ISBN 978-1-4020-4428-1. [Google Scholar]
Horticulturae 11 00366 g001
Figure 1. Different grafting methods: (a) simple grafting; (b) double grafting.
Figure 1. Different grafting methods: (a) simple grafting; (b) double grafting.
Horticulturae 11 00366 g001
Horticulturae 11 00366 g002
Figure 2. Anatomical structure of leaves of citrus with different grafting combinations (a) (HM); (b) (HDM); (c) (HAM).
Figure 2. Anatomical structure of leaves of citrus with different grafting combinations (a) (HM); (b) (HDM); (c) (HAM).
Horticulturae 11 00366 g002
Horticulturae 11 00366 g003
Figure 3. Model graph for dwarfing mechanism of dwarf interstock and rootstock. (a) Dwarfing rootstock mechanism: Reduced CTK production in the roots; (b) Dwarfing interstock mechanism: Hindered IAA transport from the roots to the scion.
Figure 3. Model graph for dwarfing mechanism of dwarf interstock and rootstock. (a) Dwarfing rootstock mechanism: Reduced CTK production in the roots; (b) Dwarfing interstock mechanism: Hindered IAA transport from the roots to the scion.
Horticulturae 11 00366 g003
Horticulturae 11 00366 g004
Figure 4. Percentage of different types of literature: (a) percentage of the number of studies on different research species; (b) percentage of the number of studies in different research fields.
Figure 4. Percentage of different types of literature: (a) percentage of the number of studies on different research species; (b) percentage of the number of studies in different research fields.
Horticulturae 11 00366 g004
Table 1. Application of double grafting.
Table 1. Application of double grafting.
TypeSpeciesInterstockRole
Fruit TreesAppleJizhen 1 and Jizhen 2Improved fruit quality and cold resistance [43]
SH6Increased keratin and wax content in fruit [47]
M27Enhanced fruit yield and quality [48]
GM256Dwarfing, cold resistance, enhanced fruit yield and quality [49]
PlumUFV 186 and UFV 286Dwarfing [50]
Havens 2BEnhanced grafting compatibility [51]
CitrusParadisi Macf.Enhanced fruit yield [52]
Rubidoux trifoliateDwarfing [53]
C. grandisAgainsted disease [54]
LemonWashington NavelImproved fruit flavor quality [55]
PearCuiguanDwarfing [56]
OHF51Dwarfing, enhanced grafting compatibility [41]
Zhongai 1Dwarfing [44]
Sugar orangeNanfengEnhanced fruit yield and quality [57]
KiwifruitMiliang 1Enhanced fruit yield and quality [58]
MangoBapakkaiRapid propagation [59]
GrapePaulsen 1103Enhanced grafting compatibility [60]
VegetablesMelonOriental Crisp and SweetEnhanced fruit appearance and flavor quality [61]
SienneEnhanced grafting compatibility and yield [62]
TroubadourEnhanced grafting compatibility [63]
TomatoFK-3aInhibit growth [64]
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Yu, J.; Zhao, Y.; Xu, B.; Tan, S.; Tong, J.; Zhang, C. Double Grafting: A Synthesis of Applications and Future Research Horizons. Horticulturae 2025, 11, 366. https://doi.org/10.3390/horticulturae11040366

AMA Style

Yu J, Zhao Y, Xu B, Tan S, Tong J, Zhang C. Double Grafting: A Synthesis of Applications and Future Research Horizons. Horticulturae. 2025; 11(4):366. https://doi.org/10.3390/horticulturae11040366

Chicago/Turabian Style

Yu, Jialing, Yinglei Zhao, Baoyu Xu, Shiyi Tan, Junhua Tong, and Chenghao Zhang. 2025. "Double Grafting: A Synthesis of Applications and Future Research Horizons" Horticulturae 11, no. 4: 366. https://doi.org/10.3390/horticulturae11040366

APA Style

Yu, J., Zhao, Y., Xu, B., Tan, S., Tong, J., & Zhang, C. (2025). Double Grafting: A Synthesis of Applications and Future Research Horizons. Horticulturae, 11(4), 366. https://doi.org/10.3390/horticulturae11040366

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop