|Better Farming Series 16 - Roots and Tubers (FAO - INADES, 1977, 58 p.)|
|How to grow yams|
Many kinds of yam bear flowers which fruit and produce seeds. So it is possible to obtain new yam plants by sowing these seeds.
But this way of propagating is no use to the farmer. The new plants grown from seed are not always like the parent plants. Often the yield is less, the tubers are much too small and of bad quality and contain a poison called dioscorine.
For all these reasons, it is better to propagate by cuttings. But here care is needed Take cuttings from ripe tubers, and not from the aerial stems, as is done with cassava. These root cuttings make plants which are like the parent plant, and give good yields.
For the cuttings use pieces of tuber or small whole tubers. To get regular sprouting and good yields, the cuttings "whether whole tubers or pieces) should weigh between 250 and 400 grammes.
The amount of yams planted represents a considerable part (about a quarter) of the harvest. That much of the harvest must be set aside and well stored for use in planting later.
Plant only fully ripe tubers. It is best to use the part of the tuber nearest the crown. This top of the tuber contains many growth buds and shoots more quickly than the rest of the tuber. For this reason, tops of tubers must all be planted in the same field.
The remaining yam tubers are planted in another field. They sprout less quickly.
With the Dioscorea bulbifera variety of yams, the bulbils can be planted in the same way as tubers. Wait until they are quite ripe, when they are easily removed from the stem.
Do not plant tubers or bulbils that are damaged, rotten or diseased.
Small yam tuber used for planting