Development of a Liquid Micropropagation System for Asparagus officinalis L.

Asparagus (Asparagus officinalis L.) is a dioecious plant that has been successfully micropropagated in vitro on solid medium, but efficiency is not optimum, especially for recalcitrant genotypes. Liquid culture has been used for propagation in other plant species and showed improvement of explant morphology as well as a high multiplication rate compared to solid culture. Thus, shoot and root growth of asparagus and overall propagation efficiency could be improved by the development of a liquid culture system. The objectives of this research were to test the effects of basal medium (DKW, MS), NAA and kinetin concentrations (0, 0.125, 0.25, 0.5µM), and types and concentrations of carbohydrates (sucrose, glucose, fructose, maltose; 0%, 3%, 6%) and growth retardants (ancymidol, paclobutrazol; 0, 0.25, 0.5, 1µM) on shoot growth in a liquid culture system. Nodal segments on DKW medium with 0.5 µM kinetin and 0.125 µM NAA, three percent glucose and 1 µM ancymidol produced the best results: a high percentage of nodal segments that initiated at least one shoot, and long, thick shoots with a large number of nodes. The effects of culture parameters on rooting are currently under analysis and plantlets will ultimately be tested for survivability in soil.