Optimizing a novel micropropagation system for Poacea in a single, multifactor experiment

A disposable, flexible film vessel was demonstrated for liquid culture micrporopagation of Poacea × ‘Cape Breeze’ and a micropropagation process was optimized for this system. Process factors involving media volume and plant density; mineral factors of ammonium and phosphate concentrations; and the important organic chemicals sucrose and benzyladenine; were simultaneously varied in the presence and absence of an inert paper substrate (40 treatment combinations for the six continuous factors, duplicated for the nominal factor, paper). Plant multiplication was enhanced by having fewest plants per vessel (10) with the largest volume of medium (90 mL), with the greatest concentrations of benyzladenine (10 µM) and phosphate (6.25 mM), in the absence of the paper. Optimal ex vitro growth, measured by dry mass increase on the mist bed required plants that had been grown under very different in vitro conditions (the smallest volume of medium per vessel (30 mL), fewest plants per vessel (10), low benzyladenine (1.6 µM), lowest phosphate (1.25 mM), in the presence of paper). Media that produced the largest in vitro plants produced plants that rapidly increased in dry mass in the greenhouse. Increasing the number of plants per vessel (30) increases the economy of the system with greater numbers of plants, but they are smaller and grow more slowly than the low-density cultures. In a small experiment using 80 vessels, separate optimal conditions in both process and media formulation were determined for both stage II and stage III cultures of Poacea . The analysis identified most important factors that drive the responses, from other significant responses with less impact.