IN VITRO CLONAL PROPAGATION, CALLUS INDUCTION AND GERMPLASM CONSERVATION OF ‘CERECILLO’ MUNTINGIA CALABURA L. (MUNTINGIACEAE)

Muntingia calabura L. (Muntingiaceae) is a fast-growing tree native to tropical America, abundant in the seasonally dry forest of the north coast of Peru. Tissue culture is an effective procedure to produce healthy plants, rapid clonal propagation and several morphogenic process. The objective of this study was to formulate an efficient method for micropropagation, morphogenesis callus induction and germplasm conservation of this species. In this study, seeds, shoot-tips and nodal segments of seedlings were used as explants, inducing various morphogenic processes in different combinations of growth regulators and osmoregulatory substances. In vitro seeds germination was 100% up to four months after the ripe fruits were collected and after 12 months the germination rate was 0.0%. The highest elongation of shoot was observed with 0.5 mg L-1 2iP (3.11 cm) although the highest number of shoots formed (18.0 and 16.5) was observed with 0.5 mg/L KIN or TDZ, respectively, after 30 days of culture. The best callus induction was obtained in 0.5 and 1.0 mg L-1 TDZ, 1.0 and 2.0 mg L-1 2,4-D, 2.0 mg L-1 NAA or 2.0 mg L1 NAA with 0.1 and 0.5 mg L-1 BAP, after 45 days of culture period. Shoot regeneration (> 10 shoots/explant) was observed with 0.1 to 2.0 mg L-1 NAA. Root induction was observed in all shoots cultured in various concentrations of IBA and NAA-GA3, after 30 days of culture. After two months, well rooted plantlets were transplanted in greenhouse conditions, however, the survival rate was less than 10%. Only in treatment with mannitol 2.0% in explants without roots, the highest in vitro conservation rate (50%) was reached, after 6 months of culture, while in the control treatment in culture medium without ABA and mannitol, but supplemented with 0.02-0.02 mg L-1 (IAA-GA3), the conservation rate reached 100%. The results demonstrated the applicability of tissue culture in the micropropagation and in vitro germplasm conservation of M. calabura.