Yam is crop that has great economic importance in the world in general and tropical West Africa region in particular. It belongs to the genus Dioscorea that produce tubers, bulbils or rhizomes, which are of economic importance. Among the numerous other species of Dioscorea genus the following ten are of economic importance: D. rotundata (poir), D. alata L., D. cayenesis Lam, D. esculenta (Lour) Burk, D. dumentorum (Kunth) Pax, D. bulbifera L., D.trifida L., D. oppositaThunb, and D. japonicaThunb. However, among these ten species only D. rotundata, D. alata, D. esculenta, D. caynesis,D. dumentorum and D. bulbifera are edible.
Yams are widely distributed across the world regions, but their distribution concentrate more in tropics and subtropics climatic regions such as; West Africa, west Indies, East African, Southeast Asia, Indochina, South America, China, Japan, Philippines, Madagascar, Central America, Caribbean, Malaysia, South Pacific Island, Korea and Papua new Guinea. In most of these countries, yam constitutes a good portion of the source of dietary calories of great proportion of their population, while in some countries like; Japan and China, yam is contributing significantly to their industrial raw materials, especially in the area of pharmaceutical and brewery industries. The trend of global production of yam shows that Africa account for about 96% of world yam production, with Nigeria alone being responsible for nearly three quarters of the world total (25.2million metric tonnes/year). Most of the world and African yam production is concentrated in the “yam belt” stretching from Cote d’Ivoire, through Ghana to Togo, Nigeria, Benin, and Cameroon, where yam is not just a food security crop but an indigenous food crop that is tied up to the socio-cultural lives of the people in the yam belt of West Africa in general and Nigeria in particular.
National Mandate and Mission Statement
Yam research programme of the National Root Crops Research Institute (NRCRI), Umudike, has the national mandate to research on the genetic improvement, production, protection, storage, processing and marketing of yams in Nigeria. Hence, our mission is to make Nigeria not only to be self-sufficient in yam production, but also have excess for export as a result, create employment and wealth and significantly improve the living standards of the rural households. We recognize that yam is regarded as the king of all the food crops in Nigeria and we want to ensure that this status quo is not only maintained but improved upon with our research.
In collaboration with Institute for International Tropical Agriculture (IITA), Ibadan, yam research programme (NRCRI) Umudike has been active with a number of breakthroughs which have led to the development and release of the following nineteen new improved varieties within a period of ten years.
Yam varieties Developed by Yam Research Programme
These improved yams have potential yields of 27 -35t/ha compared to 10t/ha of farmer varieties and they have also proven to possess good processing quality –flour, chips etc.
In an effort to solve the major challenge in yam production which is the acute scarcity of planting materials, yam research programme of NRCRI has developed an array of technologies and innovations which include;
- Modify Minisett technique using 25-35g sett size
- Mini-tuber technique using 6-10g for the production of whole mini-tuber for seed yam production.
- The Vine Cuttings Technique using healthy 3-node vines excised from vines of yams grown in buckets in a screenhouse from 70 days after planting (DAP) up to 90 DAP and planted in 270ml plastic cups filled with carbonized rice husk, for the production of minitubers/seed yams that range from 50g to 600g.
- The latest; which is seed production by cuttings technique using aeroponics system.
In the areas of nutrient requirement/soil resource management for yam production and weed management, the following technologies have been developed;
- Low input soil fertility management using rice mill waste (2.5 to 5t/ha) to reduce NPK inorganic fertilizer requirement for yam production (from 400 kg/ha to 100-200 kg/ha), has significantly increased the yield of yam crop.
- Soil fertility regeneration using leguminous cover crops has significantly increased the yield of yam crop.
- Primextra gold at 3.75kg active ingredient/ha plus 8 and 12 weeks after planting is ideal for weed control in yam
- Diutop Gold (diuron + glyphosphate) at rate 3.0Kgai/ha is ideal for weed control in yam.