Wasabia japonica, native to Japan, is of the mustard family and a perennial plant. The stem often is compared to a root or rhizome and is harvested as the edible part of the plant. Measuring 2 to 4 inches in diameter and 6 to 12 inches long, the wasabi has a flavour similar to horseradish. The spicy taste dissipates in the mouth and leaves a sweet flavour without a burning sensation.
Types of Propagation
Wasabi is propagated from offshoots, seeds or tissue culture, according to Washington State University Extension. Japanese farmers prefer starting wasabi plants by seed, which rejuvenates the crop and doesn't promote the spreading of disease. Tissue cultures from the mother plant are genetically identical, disease free and have the same potential for high quality stems. Plantlets or offshoots appear around the crown of the mother plant, again identical. However, these potentially are prone to carrying disease.
An effective way to start wasabi plants is with tissue cultures grown into plantlets. A small section of plant tissue, from the root, stem, bud or leaf, is cultured in a test tube and transferred to a greenhouse. Acclimatising the tissue cultures is an important step in procuring a viable plantlet. Transferred first to seedling trays, then potting mixture, the plantlet is allowed to develop under controlled, high humidity conditions. This process takes from a few weeks to a few months. After good root development has been established, the plantlets are ready to be transferred into a nursery bed and subsequently marketed.
Plantlets or offshoots form around the crown of the mother plant, according to Washington State University Extension. A wasabi plant will produce up to 20 offshoots that can be used as starter plants. During harvesting, the offshoots are separated from the mother plant and immediately replanted, if warranted. Plantlets that possess four to five leaves, a healthy colour and appearance, and measure approximately 1-1/2 inches or more are ready for replanting. Smaller plantlets are treated as seedlings and transferred to a nursery bed for further development.