A protocol for the in vitro establishment of Psidium guajava L. using seeds, for the conservation of native germplasm

Abstract

The guava Psidium guajava L. is a very important fruit tree for Aguascalientes. In the municipality of Calvillo, guava orchards were established with an area of more than 6 000 ha. The current problem is that it is being replaced with other crops, such as avocados, lemons, and vegetables. One solution for the conservation of these important genetic resources is germplasm banks, linked to in vitro propagation, which is a biotechnological tool that allows healthy guava plants to be reproduced in small spaces and controlled conditions. In view of this, a methodology for the in vitro establishment of guava seeds was standardized. Four treatments were evaluated in a first experiment to improve aseptic conditions, then a second experiment was conducted to determine the best in vitro culture proposal, including scarified and non-scarified seeds to define the complete protocol. In the first experiment, T3 with 0.1% Tween^® 20 (polysorbate), 6 ml L^-1 Fractal^® (citrus seed extract), 5% chlorine, and 70% ethanol showed 95% asepsis. In the second experiment, from the in vitro establishment stage, T4, with seed scarified with activated charcoal, obtained 90% germination with a length of 4.05 cm. Finally, it was found that, using scarified seed, the MS culture medium supplemented with 2 g L^-1 of activated charcoal, 0.5 mg L^-1 of BAP and 7.5 g L^-1 of agar-agar was the best to establish the in vitro reproduction protocol.