In Vitro Culture studies of Bixa orellana L: I - Differential requirements for plant regeneration from hypocotyl, leaf, cotyledonary leaf and root explants

Differential response to two basal media (MS and B5) supplemented with 2-iP and 2, 4-D; by hypocotyl, cotyledonary leaf, leaf and root were noted. B5 medium supplemented with 2-iP induced direct somatic embryogenesis in roots; callus formation in leaves and shoot bud development in hypocotyl segments. Though somatic embryos developed from root segments germinated on the same medium; healthy growth of roots occurred when 0.57 µM IAA was added to B5 medium. Shoots regenerated from hypocotyl segment showed better rooting when B5 medium was supplemented with 1.35 µM NAA. None of the explants showed growth response to B5 medium augmented with 2,4 – D. But MS medium supplemented with. 2,4 – D was effective in inducing embryogenic callus and later development into embryos from cotyledonary leaf and leaf (0.1 µM 2,4-D) and root (0.045 µM 2,4 - D) explants; whereas it could not initiate culture from the hypocotyl. These somatic embryos failed to grow further and germinate. 80% plantlets regenerated via shoot bud induction as well as through somatic embryogenesis got established on cocopeat in green house and showed 100% survival in field.