In vitro CONSERVATION OF VANILLA (Vanilla planifolia Jacks.) UNDER SLOW GROWTH CONDITIONS

Abstract

In México, vanilla (Vanilla planifolia Jacks.) is considered an endemic species that requires special protection due to severe changes in its natural habitat. Thus, development of conservations programs for rescuing this genetic resource is important. This study evaluated the effect of four concentrations (0, 10, 20 y 30 g L^-1) of two osmotic agents: mannitol and polyethylene glycol (PEG); and four concentrations (0, 1, 2 y 3 mg L^-1) of plant growth inhibitors: abscisic acid (ABA) and paclobutrazol (PAC); on survival and in-vitro growth of V. planifolia plants. In-vitro regenerated shoots, 0.5 cm tall, were used for all treatments. These shoots were grown on MS culture medium. Survival percentage, plant height, leaf number, root number and root length were recorded after 180 d in culture. Results showed a reduction in all response variables when osmotic agent concentrations increased. PAC treatments maintained 100 % survival; however, this compound affected the in-vitro phenotype of plantlets. Instead, ABA at 3 mg L^-1 caused a reduction in all variables, except survival percentage, which was 90 %. These results provide an in-vitro conservation method for V. planifolia, that extends lapses between subcultures to 180 d, without affecting their viability and normal phenotype.