Development of a clean-planting-material production system on tropical root and tuber crops, using in vitro propagated plants

Production of tropical roots and tubers is usually hampered by the lack of available clean, healthy planting material. This is caused by the fact that these crops are normally propagated asexually, which favors the accumulation of pests and pathogens, reducing yield and quality, as well as a reduction in the cropis genetic diversity. A nation wide pilot project on the production of clean asexual seed of Xanthosoma sagittifolium, X. violaceum, Zingiber officinale, Dioscorea trifida, D. alata and Manihot esculenta was initiated in Costa Rica. The strategy used was to produce 205,000 in vitro plants of these crops, and then further propagate these plants by establishing mother blocks, under isolated conditions, in the field. The protocols for micropropagation, were scaled up and now more than half of these plants are planted in the mother blocks. Yams have already finished the field stage and the planting material will be distributed among farmers in normal production areas. Prospects for the technology-transfer project are discussed.