... technique training, food processing, storage, the maintenance of planting material training. In Bacgiang province, 67-100% of farmers needed to get help in these trainings. In Thanhhoa province, however, ... provinces, the percentage of farmers using animals for preparing land was about 67-100%. On the other hand, the percentage of farmers using machines for preparing their land was rather high in ... farmers maintained and multiplied planting materials in their own garden by using the stems. There was no farmer using the tuber roots as the initiated source for the multiplication of planting materials....