High-quality seed yam production

Scaling breakthroughs in seed multiplication technology is expected to increase the productivity of yam cultivation by up to 30% in Ghana and Nigeria. The Yam Improvement for Income and Food Security in West Africa II (YIIFSWA-II) project, led by the International Institute of Tropical Agriculture (IITA), is using aeroponic propagation technology to address the increasing demand for high-quality and improved varieties of seed yam in the region.

Yam is a staple crop in West Africa. At least 1.6 million people directly depend on the yam value chain for their livelihoods. Yet, seed yam markets remain underdeveloped for reasons such as outdated seed production methods, poor distribution networks and lack of quality assurance systems. Traditional methods of seed yam production are expensive and inefficient, requiring farmers to save 25 to 30% of their harvest to plant tubers the following season. This not only reduces farmers’ incomes from harvests, but the saved seeds are often diseased, producing significantly lower yields each year. However, scientists working on the €11.32 million funded YIIFSWA project have successfully used an aeroponics system (AS) to rapidly multiply large quantities of desired varieties of seed yam tubers in a clean and cost-effective process.

Yam plantlets are planted in AS boxes and grown in a purely air or mist environment, without soil or any other aggregate medium, to produce mini-tubers. The results from YIIFSWA-I showed a 95% success rate in AS yam propagation and the multiplication rate was about 30 times faster than traditional seed yam production. The AS pruned vines start producing shoots within 2 weeks of being planted, whilst normal vines from field plants take 4-6 weeks to develop shoots. The process also reduces disease in yam crops as no soil-borne pests and diseases can infect the plants whilst they develop into mini-tubers. This is particularly vital given that national agricultural research and extension systems (NARES) were at risk of losing seed stocks of improved yam varieties due to pathogen infestation. “Yam is an important crop in Africa and addressing the seeds’ constraints will go a long way in improving the livelihoods of farmers who depend on the crop,” states Dr Robert Asiedu, IITA director for West Africa, in reference to the achievements of YIIFSWA-I.

To expand the adoption of these technologies and protocols in the private sector, in November 2016 YIIFSWA held a 2-day training workshop for 18 technicians from 11 commercial seed companies. The technicians were trained to operate high ratio propagation technologies, including AS, at the National Root Crop Research Institute in Umudike, Abia State, Nigeria. It is expected that the workshop will encourage seed yam businesses to invest in the establishment of their own AS, which have the potential to generate an annual gross income of about N16 million (€49,000) each, and lead to the formation of partnerships between private sector seed companies and NARES.