MORPHOGENETIC RESPONSE OF TWO AGAVE SPECIES REGENERATED IN VITRO

Abstract

Background: Agaves in Mexico are plants with great economic, gastronomic and cultural value. Despite the multiple forms of reproduction of plants belonging to the genus Agave, several of these species are threatened due to their slow growth, low percentage of seed viability, destruction of its habitat, excessive looting, interruption of its ripening cycle due to the use of their different organs,however, it has been posible to establish biotechnological techniques for its propagation, conservation and genetic improvement. Objective: At the present work were selected a representative species  of Agave, one of them for pulque production (A. salmiana) (As) and the other one in the production of mezcal (Agave marmorata) (Am) with the aim to establish an efficient micropropagation protocol optimizing the concentrations of the citokinin benzylaminopurine (BA) and the auxin 2,4-Dichlorophenoxyacetic acid (2,4-D), on the in vitro morphogenesis of both species. Methodology: Two in vitro culture systems were conducted in three explants (zygotic embryonic axis (E1), in vitro meristematic zone (E2) and ex vitro meristematic zone (E3)). Results: Shoots regeneration was achieved in all tested experiments; the highest number of shoots in As was 23.8 for explant using the E2 of directly regenerated in vitro germinated plants using a concentration of 10 mg L-1 of BA, while in Am 24.7 shoots/explant were obtained with 5 mg L-1 of BA using the zygotic embryonic axis who throughing a callus phase. Implications: The results obtained help to understand the importance of developing specific micropropagation protocols for each species, as well as contribuiting in the masive multiplications of A. salmiana and A. marmorata by understanding the effect of cytokinin BA and auxin 2,4-D and their combination in the formation of shoots by direct and indirect organogenesis. This provides a conservation alternative and an opportunity to startgenetic improvment programs. Conclusion: The results of this research suggest that the choice of explant, multiplication system, species and plant growth regulators are the key to obtain a greater number of shoots with high ex vitro survival rates.