Figures (1)  Tables (3)

    • Figure 1.  Schematic diagram of rootstock control scion vigour.

    • Name of crop Rootstock/treatments Traits Key findings References
      Peach K146-43, Hiawatha, Nemaguard Vegetative growth, stem elongation, and water status measurements Water relations were linked with rootstock-induced dwarfing mechanism. [25]
      Tree canopies were partially covered (0, ~30, and ~60%), and three rootstocks were used, including (K146-43, Hiawatha, and Nemaguard) Water usage and transport Tree water status were possibly involved in the dwarfing of scion growth by rootstocks. [30]
      ‘K146-43’, ‘Nemaguard’ and ‘P30-135’ Theoretical axial xylem conductance Larger vessel dimensions were found in the vigourous rootstock than dwarfing rootstocks (‘K146-43’). The vessel density per xylem area in ‘Nemaguard’ rootstock was also lower than those of the ‘K146-43’ and ‘P30-135’ rootstocks. [31]
      Apple JM5, JM1, JM7, JM2, and Marubakai Anatomical traits, sap flow, and hydraulic conductance The degree of dwarfing were closely associated with the phloem to xylem ratios of roots. Therefore, it could be a useful index for screening the dwarfing potential of rootstocks. [32]
      Baleng, Chistock-1, SH.6/Baleng, SH.6/Chistock-1, M.26, M.9, SH.6, B.9 Hydraulic conductance, non-structural carbohydrates, leaf anatomy, gas exchange, and chlorophyll fluorescence, The reduction of photosynthetic rate has been attributed to the decreased hydraulic conductivity, which causes a decline in instantaneous photosynthetic assimilation of the whole canopy. [29]
      Pear Dwarfing and vigourous rootstocks Anatomical investigations of young stems and mature leaves Dwarfing rootstock had lower vessel diameter and vessel density compared with the vigourous type. The lower growth vigour of dwarf pear may be associated with anatomical characteristics. [26]
      Cherry Gisela 5, Mahaleb, Mazzard, Colt PHL-A Stem and root anatomical characteristics and theoretical hydraulic conductance (kh) Lower hydraulic conductance in dwarfing rootstock were possibly due to smaller vessel lumens and percentage. [28]
      Citrus Troyer citrange, Rough lemon, Sweet lime, Carrizo citrange, sour orange and Flying dragon Anatomical features of leaf, stem and root Vigourous rootstocks possessed larger vessel elements in the stem and roots as well as lower proportions of bark (phloem) compared with dwarfing rootstocks. [27]
      Flying Dragon and Rubidoux trifoliate rootstocks Leaf water potential, hydraulic resistance, gas exchange measurements, xylem anatomy, and 13C photoassimilates transport Lowered hydraulic conductance might be the possible reason for rootstock-induced dwarfing in citrus scion when grafted with dwarfing rootstock. [33]
      Olive Cairo7, Manzanill, Aggezi, Frantoio, Coratina, Koroneiki, Picua, Arbequina, Teffahi, Chemlali, Dolce Histological studies of stem Lower phloem and higher xylem (%) in vigourous rootstock are correlated with growth vigour. [34]
      Mango Alphonso, Fajri Kalan, Sukkary and Zebda, Tommy Atkins, Sediek, Keitt, 13/1, Naomi, Kent, Mabrouka, Ewais, Hindi Besinnara, Maya Anatomical studies of stem Xylem and phloem percentage could be used as a dwarf indicator for the screening of rootstocks. [35]

      Table 1.  Important physiological and anatomical evidences underlying rootstock induced vigour control.

    • Name of crop Rootstock Scion Traits Key findings References
      Peach Mr.S.2/5, GF677, Armking 'Armking' Xylem exudates Tree growth was positively associated with the xylem transport rate of cytokinin. [37]
      Apple MM.111, M.27, M.7, and M.9 MM.111, M.9, M.7, M.27, Gala, Fuji Scion above the graft union, rootstock below the graft union, leaf, roots, exudates, current year stem Reduced GA levels and higher ABA levels were linked with a degree of dwarfing. [48]
      'Royal Gala', 'M.793', 'MM.106', and 'M.9' 'Royal Gala' Application of growth regulators, Measurements of tree growth, shoot-root-shoot hormonal signalling Dwarfing rootstocks reduce the basipetal IAA transport to the root, thus decrease the amount of root synthesized gibberellin and cytokinin, transported to the aerial part. [34]
      'Royal Gala', 'M.793', 'MM.106' and 'M.9' 'Royal Gala' Measurements of scion growth, root growth, total growth per tree, total dry weight quantification of indole-3-acetic acid, cytokinins, and gibberellins. Size-controlling apple rootstocks may restrict root-produced GA19 supplied to aerial part. [18]
      'M.9', 'MM', and interstock combinations, 'M.9'/'MM' 'Red Fuji' Hormone determination and the expression of hormone related genes. Lower expression levels of IPT3 gene in dwarfing rootstocks resulted in lowered cytokinin synthesis in roots, which resulted in inadequate supply of cytokinin to the aerial parts, resulting in a reduction of auxin content and scion growth. [49]
      M.9 and Baleng Crab Scion/rootstock combinations (Fuji/M9), Fuji/
      M9/Baleng Crab, Fuji/Baleng Crab      		 Determination of phytohormone contents and relative expressions of MdPINs genes Dwarfing effect was initiated by inherently lower expression of MdPIN8 in M9 interstem. [50]
      'M.9' and 'MM.106' 'Fuji' Investigation of tree growth and measurement of IAA to explain the function of auxin in controlling the dwarfing rootstocks The lower amount of auxin transported from the shoots along with the root auxin synthesis deficiencies reduced the root growth and then decreased the supply of root-produced substances to the shoots in dwarfing rootstocks. [33]
      'M27', 'M9' and 'M793' 'Royal Gala' ('RG') Non-structural carbohydrate analysis, RNA sequencing and quantitative reverse transcriptase PCR. Over-accumulation flavonoids and reduced MdAUX1 and MdLAX2 expression contribute to the reduced auxin transport observed in dwarfing rootstocks. [51]
      Six kinds of apple rootstock ('Mailing 9', 'Mailing 26', 'Budagovsky 9', 'Malus xiaojinensis', 'Malus robusta', 'Malus baccata') and two grafting complexes ('Fuji/M9' and 'Fuji/Mr') 'Fuji' Trans-zeatin determination, and expression of cytokinin metabolic pathway genes Low IPT5b expression with high-level methylations in the promoter region, leading to poor root trans-zeatin biosynthesis in the M9 rootstock, which may induce dwarfing. [52]
      Pear Dwarf and standard rootstocks − Comparative transcriptomic analysis between standard and dwarf pears of the young apical stem Major differences between dwarf and standard pears were associated with ribosome biogenesis and photosynthesis. [53]
      Zhongai 1 and Jinxiang − RNA-Seq analysis and the determination of phytohormones (GA3, IAA, and ABA) The dwarf mechanism of different genotypes may be diverse, and even in the same genotype, the dwarf character may be controlled by many factors [54]
      Sweet cherry Ten different size controlling (Prunus Mahaleb L.) genotypes − Vegetative growth parameters and hormonal ratio The proportion of ABA/IAA hormones was lesser in sturdy rootstocks than that in the dwarf rootstocks. Moreover, the available ABA concentration demonstrates a relationship between growth vigour and ABA in shoot bark of rootstock. [47]
      Litchi vigourous cultivar (Feizixiao) and dwarf cultivar (Ziniangxi) − Anatomical observation, transcriptome profiling, and mechanisms of litchi dwarfism Upregulation of GA2ox in dwarf cultivar (ZNX) samples only, showing GA may assume a significant role in managing an immense difference between cultivars of dwarf and vigourous litchi cultivars. [43]
      Sweet Persimmon Rootstock (Diospyros lotus L.) and interstock/rootstock (Nantong-xiaofangshi/Diospyros lotus L.) 'Kanshu' Hormone levels and water conductance The expression of GA2ox, DELLA, and SPINDLY genes were upregulated and associated with a decrease level of GA in scions grafted on the interstock. [55]
      Citrus Fragrant orange, Rough lemon, Shatangju mandarinCanton lemon, and Red tangerine 'Shatangju' Dwarfing mechanisms and the influence of rootstock on scion growth IAA and GA were significantly and positively related to growth vigour. the qRT-PCR analysis showed that expression levels of ARF1, ARF8, GH3, and IAA4 were negatively correlated with the growth vigour and IAA content. [56]

      Table 2.  Important hormonal and carbohydrates evidences underlying rootstock induced vigour control.

    • Name of crop Family Name of rootstocks Name of scion cultivar Traits References
      Apple (Malus domestica Borkh.) Rosaceae M.9, M.26, Chistock-1 and Baleng 'Red Fuji' Dwarfing traits, scion morphology, and mineral concentration [8]
      M.9, MM.106, MM.111 and local seedling (Malus domestic cv. 'Local' 'Golden Delicious' and 'Royal Gala' Growth vigour and mineral concentration [22]
      M. hupehensis Rehd., M. prunifolia Borkh., M. robusta Rehd., M. sieversii Roem, and M. rockii − Plant growth and potassium (K) use efficiency [58]
      Peach (Prunus persica L.) Rosaceae Seven hexaploid plum rootstocks (Adesoto, Monpol, Montizo, P. Soto 67 AD, PM 105 AD, GF 655/2 and Benasque) 'Catherina' Leaf mineral concentration and fruit quality traits [59]
      almond × peach hybrids rootstocks (Adafuel, Adarcias, GF 677, Cadaman, Garnem and Felinem) Queen Giant and Tebana Vigour, yield and mineral concentration [52]
      Pear (Pyrus communis L.) Rosaceae Seedlings of Local and colonal pyrus, MA, MC and BA 29 Quince (Cydonia oblonga M.) Santa Maria Fruit quality, yield and leaf uptake of mineral elements [63]
      Plums (Prunus domestica L.) Rosaceae Marianna GF8-1 and Marianna GF10-2 (Prunus cerasifera × munsoniana) Rainha Claudia Verde Tree vigour, fruit quality and fruit mineral concentration [64]
      Apricot (Prunus armeniaca L.) Rosaceae Evrica, Krymsk 86, Torinel, PAC 00-08 and PADAC 01-47 Two apricot cultivars ('E-101' and 'E-404') Fruit yield and quality [65]
      Pistachio (Pistacia vera L.) Anacardiaceae Badami-sefid, Sarakhsi, Kalle-ghouchi, Daneshmandi, Barg-Seyah and Akbari Akbari and Barg-seyah Mineral uptake [66]
      Grape (Vitis
      vinifera L.)      		 Vitaceae 'Couderc 161-49', 'Sori', 'Kober 125AA', 'Börner', 'Kober 5BB' 'Regent' Mineral nutrition and heavy metals uptake [67]
      Two different rootstocks including (low and high vigour) Cabernet Sauvignon Control of scion vigour, mineral nutrition and whole plant biomass [68]
      'IAC 766', 'IAC 572', 'IAC 313' and 'IAC 571-6' 'Venus' Yield and nutrient uptake [69]
      Citrus Rutaceae Nine different citrus rootstocks Kinnow mandarin (Citrus reticulata Blanco L.) Leaf nutrient status, yield and fruit quality [70]
      Rough lemon, Karna Khatta, Carrizo citrange, Rangpur lime, Troyer citrange, Jatti Khatti and sour orange Kinnow mandarin Root morphology, mineral uptake and nutrient absorption capacities [71]

      Table 3.  Influence of rootstock on the vegetative growth, yield, fruit quality, and mineral uptake of grafted plants.