In vitro CONSERVATION OF Agave spp. GERMPLASM UNDER SLOW GROWTH CONDITIONS

Abstract

An in vitro conservation system under slow growth conditions was developed for the threatened species Agave bracteosa, A. chiapensis, A. nizandensis, A. ornithobroma, A. peacockii, A. titanota y A. victoria reginae, and for non-sustainably exploited species A. cupreata, A. karwinskii and A. potatorum, used for “mezcal” production. The objective was to provide a tool for medium-term germplasm conservation of these species. The addition of osmotic agents to the culture media (manitol or sorbitol at 50 g L^-1) reduces in vitro tissue growth rate, measured as fresh weight increase. The slow growth rate extends lapses between subcultures from 75 d to 10 months without affecting their viability or complete plant regeneration capacity in media with cytokinins and without osmotic agents. Regeneration efficiencies between 5.8 and 20.6 shoots per explant were obtained in tissues conserved during 10 months with the addition of osmotic agents. Regenerated shoots were rooted and adapted to soil with 92 and 80 % average efficiencies, respectively. It is concluded that with this system, it is possible to establish in vitro germplasm banks, in the medium term, that contribute to the conservation and rational use of these species.