Sources and Frequency of Somaclonal Variation

Abstract

Plant tissue culture was introduced to the public as an asexual method to propagate plants rapidly and reliably. Many ornamental, fruit, and vegetable crops are now routinely propagated commercially in vitro. The ease of tissue culture propagation has revitalized certain ornamental industries and facilitated the rapid introduction of new cultivars. In spite of new cultivars and in spite of these successes, some commercial propagators are now advertising that their plants are “not from tissue culture,” while others continue to advertise that their plants are tissue culture-derived (e.g., American Nurseryman, Apr. 1990, Classified Section, “Daylilies”). What is going on? Commercial nurseries are now encountering the ubiquitous phenomenon of somaclonal (tissue culture-derived) variation (Anonymous, 1989; Knuttel, 1989). Since all cells of an organism are derived from a single cell, researchers assumed that plants derived from cells of a mother plant would yield plants identical to the mother plant. However, according to Scowcroft (1985), who has researched somaclonal variation since it was formally acknowledged, “clonal uniformity is now recognized as the exception rather than the rule.”