Artificial Induction of Polyploidy in Orchids by the Use of Colchicine

Abstract

In the orchid industry, polyploidy has come to assume a prominent role in the production of superior types. Because polyploid orchids have been established to be generally superior to their diploid counterparts, the artificial induction of polyploidy assumes particular significance. If somatic doubling can be induced at will with a chemical such as colchicine, superior horticultural varieties might be obtained immediately. Such induced tetraploids might be utilized in breeding further polyploids. In the course of an extensive breeding program in orchids, a relatively high degree of sterility has been encountered among intergeneric hybrids and to a lesser degree among interspecific hybrids. Restoration of fertility among the sterile hybrids was found desirable in order to advance the breeding program. In accordance with these considerations, attempts were made to find practical methods for inducing polyploids in selected orchid groups by the use of colchicine. This investigation also entailed the study of the characteristics of the induced polyploids and comparing them with their diploid counterparts with respect to morphological differences.