In Vitro Propagation of the Kenyan Yam (Dioscorea spp.)

Abstract

Yam tuber is used as food where it provides cheap, starch-rich food for the hot humid tropics. In Kenya yam is mainly boiled, fried or roasted although a minority of consumers also processit into flour for use in some baked products. Yams are propagated vegetatively using corms and tuber-sets. In general vegetative propagation is associated with the rapid spread of diseases and is cumbersome. The main objective of this studywas to developan efficient in vitromass propagation protocol for this particular species. The work involved establishment of the best sterilization procedure for the explants that were initially grown in pots in a screenhouseand thenexposed to different levels of commercial bleach (3.5% chlorine). This wasfollowed by culturing the nodal cuttings from the explants in MS media supplemented with different levels of growth regulators. The two step-wise sterilization procedure using commercial bleach was found to be the best and hence recommended for future work. There weresignificant differences among the treatments with the combination of BAP and IAA at levels of 0.5mg/l of BAP + 0.02mg/l of IAA giving the best results for plantlet regeneration. In vitrorooting was achieved without the use of hormones and the most vigorously growing plantlets acclimatized in the greenhouse. Inconclusion, the study foundthat it is possible to propagate yams in vitroand with the adoption of this protocol formicro-shootgrowth, increased rates of multiplication can be achieved. This technique can then be exploited to generate clean, disease-free material both for mass propagation and experimental work.