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The mango has proved difficult to micropropagate by shoot tip and nodal culture, primarily because of the rapid release of toxic phenolic compounds into the plant growth medium and endogenous bacterial contaminants.

Yang and Ludders (1993) described shoot tip and nodal culture for micropropagating 2-year-old seedlings of polyembryonic ‘Gomera’, ‘Sabre’, ‘Turpentine’ and ‘13-1’. Plant growth medium (G formulation) supplemented with 4.4 μM benzyladenine (BA), 4.6 μM zeatin, 9.8 μM dimethylallylaminopurine (2iP), 2.9 μM indoleacetic acid (IAA), 2.5 μM indolebutyric acid (IBA), 300 mg/l glutamine and 300 mg/l casein hydrolysate caused axillary bud proliferation, although rooting of in vitro shoots was not reported. Monoembryonic cultivars cannot use this procedure as it involved juvenile nucellar seedlings.

Controlling microbial infestations of shoot tip and nodal cultures has been difficult. Hare Krishna (2006) applied imidazole as a daily spray for 3 days on field-grown plants. There have been several reports of attempts to reduce phenolic exudation from shoot tip explants: (i) shoots from new vegetative flushes (Thomas and Ravindra, 1997); (ii) dipping in 0.5% polyvinylpyrrolidone (PVP) and 2.0% sucrose for 30 s (Chavan et al., 2000); (iii) dipping in a solution of 100 mg ascorbic acid and 50 mg citric acid (per 100 ml) for 30 s, followed by culture on medium with 0.05% PVP. Sharma and Singh (2002) observed that polyphenol oxidase (PPO) is reduced if shoots from decapitated trees are etiolated. ‘Bhadauran’ shoot tips have the highest PPO activity and the lowest explant survival rate (Sharma and Singh, 2002); whereas ‘Tommy Atkins’ had the lowest PPO activity and the highest survival rate.

Phenols, peroxidase and PPO activities are reduced in etiolated mango shoots together with greater shoot survival and reduced necrosis (Hare Krishna, 2006). The in vitro growth response of mango shoots from greenhouse-grown seedlings was better than field-grown plants (Hare Krishna et al., 2008). Chandra et al. (2004) suggested that shoots should be defoliated and sprayed with 0.1% bavistin (carbendazim) and 0.1% gentamicin containing 8.87 μM BA and 5.77 μM gibberellic acid (GA₃) on alternate days for c.2 weeks. Harvested shoots were agitated in an antioxidant solution containing 70 mg/l ascorbic acid and 50 mg/l citric acid for 30 min prior to culture on plant growth medium. This treatment resulted in 80% sterile cultures.