Factors that Influence Vegetative Bud Development in Rootstock Segments of Dioscorea composita and D. floribunda

Abstract

Selections of D. composita and D. floribunda can be propagated vegetatively from segments of the tuberous rootstock. Dormancy of the rootstock delays bud development and results in uneven sprouting and high loss from rot of the planted segments. The degree of dormancy in the rootstock ap pears to be affected by the genetic makeup of the plant, by a dormancy gradient that increases from crown to tip of the rootstock, and by the state of growth of the plant from which the rootstocks are taken. A 31° C. temperature significantly stimulated bud development in the D. floribunda selections. Treatment of both D. composita and D. floribunda sections with dosages of 0.06 and 0.12 ml. of ethylene chlorohydrin showed highly significant stimulation of bud development. Relatively even sprouting and accelerated bud development were obtained experimentally by using rootstocks from plants in active growth, by using segments from intermediate areas and by breaking the dormancy of the rootstocks.