Efficient production of vigorous passion fruit rootstock for in vitro grafting

In Vitro Micrografting of Horticultural Plants: Method Development and the Use for Micropropagation

“…The survival rate during acclimatization of micrografted plants varies among species. For example, in apple, survival rate of grafted plants reached 100% [82], for almond it was 85-100% [92], it was 82% in cacao [36], and 75% in passionfruit [26], whereas in Tahitian lime and Valencia orange, survival rates ranged from 47 to 50%, respectively [87]. Contrasting results were also reported by Kobayashi et al [93] in micrografting of sweet orange buds derived from organogenesis.…”

“…Following the advent of in vitro plant tissue culturing in the early 1900s [7], a grafting system using tissue culture (micrografting) was first demonstrated by Doorenbos [8] in ivy and then Holmes [9] in chrysanthemum in the 1950s, and was later developed and standardized for virus eradication from citrus species by Murashige et al [10] and Navarro et al [11]. To date, in vitro micrografting (IVM) has been widely applied (1) in pathogen management to facilitate the eradication, indexing and transmission of pathogens, as well as the assessments of graft incompatibility induced by pathogen infection [11][12][13][14][15]; (2) to facilitate in vitro rooting [16][17][18][19], to invigorate regenerating plant tissue cultures during micropropagation [19][20][21][22], and for the rapid assessment of graft compatibility [23][24][25][26]; and (3) in studies focusing on the molecular mechanism of graft compatibility, as well as the exchange and trafficking of macromolecules between scions and rootstocks [27][28][29][30].…”

“…This stable in vitro environment and the probable pathogen-free status of micro-scion/rootstock may favor callus formation and rapid establishment of vascular reconnection between scions and rootstocks required for grafting success [34,35]. Micrografting protocols have been developed for many fruit crops including almond [18], apple [36], apricot [23], avocado [37], cacao [38], cashew [39], cherimoya [19], cherry [21], citrus [40,41], guava [4], grape [34], jujube [42], mulberry [43], hazelnut [44], kiwifruit [25], passion fruit [26], olive [45], peach [46], pear [47], pistachio [17], plum [48], walnut [49,50], and watermelon [51].…”

“…The presence of roots on the rootstock is essential for micrografted plants to survive acclimatization. Hieu et al [26] found that the micrografted plants of passion fruit without roots did not survive acclimatization; plants with roots formed in vitro achieved the highest survival rate during the acclimatization phase. The survival rate during acclimatization of micrografted plants varies among species.…”

“…In addition, the phytohormones applied in the culture medium can also affect the development of micrografts. Cytokinin and auxin are the most frequently used phytohormones in growth media when micrografts are used [22,26,91]. In pistachio, Onay et al [17] found that the micrografts cultured in a growth medium with 2.22 µM 6-benzylaminopurine (BAP) were significantly more successful (72%) than those cultured in medium containing 2.46 µM indole-3-butyric acid (IBA) (36%) or in phytohormone-free medium (47%).…”