Induction of Polyploid of Dendrobium devonianum

The polyploid breeding technique was used to induce polyploid of Dendrobium devonianum,an orchid occurring in the tropics of Yunnan with ornamental and medicinal values.The materials for polyploid breeding were in vitro seedlings of diploids.The polyploid plants could be induced in a short time with colchicines as mutagen.It resulted in the best inductive effect to use 0.03% colchicines to deal with the in vitro seedlings of diploids for 24 hours.The polyploid plants were different from those of diploids in morphology,stoma diameter,chromosome numbers,and DNA fingerprints.The in vitro seedlings of polyploid plant showed advantageous characteristics such as thicker stems and leaves.It is a successful case to apply polyploid breeding technique into the tropical orchid breeding in China.