Productivity and Curcumin Content of In vitro Regenerated Curcuma Plants

抄録

This study compared the growth and curcumin contents of in vitro regenerated and conventionally propagated Curcuma longa, C. aromatic, and C. zedoaria plants. The in vitro regenerated plants (IRPs) of all three species had an acceptable survival rate in the field (≥93%), suggesting that it is feasible to transplant Curcuma IRPs. In C. longa, the shoot and total rhizome dry weights (DWs) of conventionally propagated plants (CPPs) were 137.3 and 225.2 g, respectively, which were similar to or lower than the corresponding values in IRPs that were transplanted in April and similar to the corresponding values in IRPs that were transplanted in May. In C. aromatic and C. zedoaria, there was no significant difference in shoot growth between IRPs that were transplanted in April and CPPs, but the total rhizome DWs tended to be higher in the latter. In all three species, the shoot growth and rhizome yield of the IRPs increased as the planting time was brought forward, and there was a significant positive correlation between the shoot and rhizome DWs in the IRPs across all transplanting times (r = 0.88, p < 0.01). The curcumin contents of the rhizomes of C. longa and C. aromatic decreased as the transplanting time was delayed, but there was no significant difference in the curcumin contents of the rhizomes of IRPs that were transplanted in April and May and CPPs. These findings suggest that acceptable rhizome and curcumin yields can be obtained by cultivating IRPs of Curcuma spp. However, it is also necessary to consider bringing the planting time forward to increase these yields.