ISSN: 0041-3216

ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 60 Number 2
Research Papers
Effect of thiourea treatments on the induction and development of buds in white yam (Dioscorea rotundata, Poir.) tubers
Ivan Samarawira
The cortex of trimmed and untrimmed ware tubers of white yam (Dioscorea rotundata, Polr.) was segmented by cutting narrow grooves longitudinally and horizontally into the cortex and the tubers were buried in pro-pagators, in a randomized complete-block-design with five replications, following treatments with 1.0, 1.5, 2.0 and 2.5% thiourea solutions, with water as control. A substantial number of buds was induced to develop on the upper and middle segments of the trimmed tubers, whereas bud development occurred only towards the 'head' end of untrimmed tubers. The 2.0% thiourea treatment was consistently better than the other treatments. The development of a satisfactory number of buds in the fourth week would appear to suggest that all propagules could be excised simultaneously for planting in the fourth week. The technique appears to be feasible for increasing the multiplication ratio in white yam.
Keywords: Dioscorea rotundata, Poir.; Tubers; Buds; Thiourea