Techniques and Problems in the Propagation of Sapogenin-bearing Yams from Stem Cuttings

Abstract

Sapogenin-bearing yams, the sources of steroid hormones, were propagated by leaf-stem cuttings, which is a new method of propagation for this type of yam. Experiments were conducted to determine the effect of such factors as the season of the year, position of the leaf on the stem, and treatments with hormones and fungicides on the propagation of two species of medicinal yams (D. composita and D. floribunda) from leaf-stem cuttings. It was found that an important factor in the propagation from leaf-stem is the use of young, vigorous, succulent leaves. Leaves produced during the spring have these characteristics. Cuttings can be made from all available leaves. It was also found that hormones stimulate root growth and that, if good sanitation is practiced, fungicides are not necessary. Treatments with ethylene chlorohydrin in sealed containers, at the rate of 0.25 ml. per liter of air space, stimulate shoot growth. The two species tested are completely different in behavior with respect to their ability to respond to the treatments applied. The cuttings should be treated by an intermittent mist-spray schedule which keeps them damp. Differences in rootability resulting from the position of the leaf on the stem were significant in both species. The treatments given to cuttings prior to rooting influenced their survival and rooting.