Polyploidy induction of clone of Eucalyptus grandis with colchicine

The study was conducted to find the dependency of polyploid inductivity rate of axillary buds of Eucalyptus grandis clone Eg5 with colchicine on treatment conditions by applying Plackkett-Burman design and uniform design. According to regression analysis, the functional relation equation between polyploid inductivity rate and independent variables including colchicines concentration and soaking time was found with Adj R(2) as 0.9366 which is ideal. The maximum inductivity rate can reach 51% when the soaking time is 26.2 h and the colchicines concentration is 0.21%. The study result shows that inductivity rises at first and drops later with continuous increases of colchicine concentration and soaking time. The inductivity drops, because of the mass mortality of treated axillary buds. The difference of tree height between tetraploid plants and untreated plants was significant while the difference of ground diameter between them did not reach significant level.