Dioscoreaceae

Abstract: Part 1 The general morphology of yams: the annual vegetative system the vegetative reproductive system the sexual reproductive system. Part 2 The yam tuber - its structure, use and storage: the morphological and anatomical structures of the tuber bases for the use of the tuber the tuber's uses storing the yam tuber in a cool environment. Part 3 Cropping techniques: traditional cropping techniques industrial yam cultivation. Part 4 The growth and development of yams: clonal generations flowering and fruiting growth and development of plants resulting from seeds pluriannual development. Part 5 Prospects for crop improvement: results from experiments on cropping techniques protecting crops against pests and parasites choice of cultivars and varietal creations. Part 6 Systematics, distribution, evolution and phyllogenesis of Dioscoreasceae: the main factors involved in Dioscoreaceae classification the main groups of food yams some considerations on the development of the Dioscoreaceae. Part 7 Yams in society: ancient civilizations of the yam the development of yam-based production systems production and marketing. Conclusion: Some research proposals some suggestions for yam research and development.

Abstract: Agrobacterium tumefaciens induces tumorous proliferations on dicotyledonous plants by transferring a specific region (T-DNA) of its tumour-inducing (Ti) plasmid into wound-activated plant cells, where it becomes integrated into nuclear DNA1 and expressed2. The vir region of the Ti plasmid is essential for T-DNA transfer3,4 and is induced by specific wound substances from plants5–9. Agrobacterium is therefore a powerful tool for gene transfer to plants, but with some exceptions10–14 this method does not seem to be applicable to the commercially important monocotyledonous crops. We report here transformation of the monocotyledonous crop plant Dioscorea bulbifera (yam) with agrobacteria preincubated by wound substances from dicotyledons, leading to crown gall tumour formation. Moreover, we present direct evidence for the integration of T-DNA into the nuclear genome of this monocotyledonous crop.