The Effects of Benzyladenine and Meta-topolin on in vitro Shoot Regeneration of a Citrus Citrandarin Rootstock

The effect of 6-benzyladeninepurine (BA) and meta-topolin (mT) on the three responses shoot quality, numbers of epicotyl explants producing shoots, and the number of shoots greater than 2 mm from citrus rootstock US-812 (Citrus reticulata x Poncirus trifoliata) epicotyl explants was determined. The experiment was designed as a mixture-amount. The two mixture components, BA and mT were varied proportionally from 0 BA:1 mT to 1 BA:0 mT and the amount of total cytokinin varied from 1 to 50 p,M. Models developed for each of the three measured responses were highly significant. Results were as follows: first, the three responses were similar over the design space; second, no synergistic or antagonistic interactions were detected; and, third, BA and mT resulted in similar responses, but at substantially different amounts - BA at 1 p,M was essentially equivalent to mT at 13.25 - 37.75 p,M.