A Method for Acclimatization of Micropropagated Vanilla Plantlets Using Arbuscular Mycorrhizal Fungi

Arbuscular mycorrhizal fungi (AMF) make associations with the roots of different plant species to improve crop development in a sustainable way. The objective of the present study was to evaluate the effect of different doses of AMF (Rhizophagus intraradices) on the ex vitro development of vanilla (Vanilla planifolia Jacks. ex Andrews) plantlets. Vanilla plantlets were inoculated with different doses: 0, 50, 100, 200, and 300 spores per plantlet (s/p) of R. intraradices during the acclimatization stage. At 120 days of inoculation, the colonization percentage, survival percentage, different growth variables, dry matter, chlorophyll and macro and micronutrient contents of the plantlets were evaluated. An effect of the AMF doses on the evaluated variables was observed. AMF at a dose of 50 s/p showed an efficient symbiotic interaction according to the development variables evaluated. At this dose, with 17% colonization, 96% survival was obtained, while, at doses of 200 and 300 s/p, with 65.3% and 73.3% colonization, the lowest survival percentages were observed, with 63.3% and 53.3%, respectively. In addition, AMF had an effect on the content of the nutrients N, P, Zn, Mn and B, while, for K, Ca, Mg, Fe and Cu, no significant differences were observed. Applying suitable inoculation doses of R. intraradices in vanilla plantlets under greenhouse conditions is an alternative to improve survival and physiological development during acclimatization and allows conditioning prior to transplanting for cultivation.