Evaluation of conditions for in vitro storage of commercial and minor grapevine (Vitis vinifera L.) cultivars

In vitro culture represents a tool for the ex situ conservation of a high number of sanitised plants in a reduced space. However, the culture media and/or other growing conditions need to be optimised to minimising plant growth and storage cost. Growth on MW medium was evaluated in the commercial cultivars ‘Airén’, ‘Bobal’, ‘Chardonnay’, ‘Garnacha Blanca’, ‘Moscatel de Alejandría’, ‘Moscatel de Grano Menudo’, ‘Pedro Ximénez’, ‘Pinot Blanc’, ‘Pinot Gris’, ‘Sauvignon Blanc’, and ‘Tempranillo’; the minor cultivars ‘Chelva’, ‘Valencí Negre’, ‘Valencí Blanc’, and ‘Verdil’; and the endangered cv. ‘Esclafacherre’. Different growth rates were observed among cultivars: those with faster growth need to be subcultured every 1.5–2.0 months; those with the slowest growth every 3.5–4.0 months. The effect of halving the sucrose in MW reduced the growth of the cultivars that grew faster without compromising survival. When IBA was removed from MW, growth was also reduced in some cultivars. Therefore, small modifications of the MW composition are adequate for grapevine in vitro storage under standard incubation conditions. This is an advantage with respect to the change of temperature used in other work to achieve growth reduction, and allows the use of the same chamber for different in vitro culture procedures.