Polyploidy induction in the crandon clone of Populus alba × P. grandidentata by colchicine treatment

Crandon clone of Populus alba×P. grandidentata was treated with various colchicine concentrations and treatment durations to determine the best method for inducing polyploidy through in vitro treatment of axillary buds. Colchiploid shoots were only produced from in vivo, but not from in vitro colchicine treatments. Most colchiploid shoots originated from buds that were treated 24 h. duration with 1% colchicine solution and 48 h. duration with 2% colchicine solution. Twelve colchiploid shoots produced from in vivo colchicine treatment continued to exhibit the chimera leaf shape after cuttings and have mixed chromosome numbers, 2n (38) and 4n (76). The adventitious shoots produced from chimeric leaf discs through in vitro culture appeared either normal or colchiploid leaf shape with thicker stem diameter. The colchiploid adventitious shoots had the mixed 2n-4n chromosome numbers.