Both reproductive and vegetative portions of many fruit crops have been studied in tissue culture. Most investigations have dealt with three primary subjects: the production of callus, proliferation of axillary and adventitious buds, and rooting. In a recent survey of tissue culturalists, R. H. Zimmerman reported that most investigators working with fruit crops used a modification of the T. Murashige and F. Skoog high mineral salts medium at some stage of culture. The problem of determining the organic compounds essential for plant growth in tissue culture was particularly difficult for early investigators since few natural plant constituents were known when plant tissue cultures began. One of the most common organic complexes used in tissue culture is agar. Since agar is produced from a red algae that is harvested from the ocean, each batch is slightly different and may represent a source of variation in an experiment that could be especially pronounced between batches of media.