A reproducible micropropagation protocol for tamarillo (Solanum betaceum) via somatic embryogenesis was established in this study. Three types of explants were assayed: leaves, hypocotyls and zygotic embryos; all of them obtained from in vitro cultured seeds. Different concentrations of auxins 2, 4-D (2,4-dichlorophenoxyacetic acid) and NAA (a- napthaleneacetic acid) and sucrose were tested to find out an appropriate medium that stimulated the formation of embryogenic calli. MS medium supplemented with 5 mg/L of NAA and 90 g/L of sucrose (pH 5.8) induced somatic embryos formation from the upper thirds of hypocotyls and from zygotic embryos. One-hundred percent of the explants derived from zygotic embryos and hypocotyls developed big whitish calli. However, only 40 % of the hypocotyl-derived calli and 70 % of the zygotic embryo-derived calli produced somatic embryos. The results showed that somatic embryos were obtained after a four-week incubation period in MS medium supplemented with 5 mg/L of NAA and 90 g/L of sucrose. The somatic embryos grew rapidly and produced plantlets with normal phenotypes. These results suggest that this technique could be applied for large scale production of Tamarillo and other agronomically important Andean fruit crops.
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