Protocols were established for micropropagation
and coloured callus production of Echinocereus cinerascens, a
cactus that is highly in demand for the horticultural industry.
An efficient micropropagation system facilitates rapid shoot
production of this threatened species. The present study
investigates the effects of the plant growth regulators NAA
and BAP on shoot and coloured callus induction. Shoots were
produced from axillary buds and coloured callus from stem
explants cultured on Murashige and Skoog (MS) medium
supplemented with different concentrations of NAA and BAP
(0.5, 1.0, 1.5, 2.0 mg l-1) applied singly and in combinations.
The medium that resulted in the highest mean number of
shoots produced wasMS supplemented with 2.0 mg l-1 NAA
and 1.5 mg l-1 BAP. In general, media with combinations of
BAP and NAA were more effective than NAA or BAP alone
in inducing shoots. NAA alone resulted in significantly fewer
shoots than BAP alone.Most stem explants produced coloured
callus in all treatments. Green calluswas induced in over 80 %
of explants in all treatments in which the hormones were
applied singly, while yellow callus was induced in 80–100 %
of explants in half of the treatments with hormone combinations.
In contrast, the occurrence of pink callus was less prevalent
than green and yellow callus. Pink callus was induced
in 3–40 % of explants when treatments were added with
single BAP or NAA and in 7–63 % of explants treated with
combinations of BAP and NAA.