Researchers successfully grow “seed yams in the air”

L-R: Dr Maroya, Annang, Asiedu, Aighewi and members of the press at
 the unveiling of the new seed yam propagation technique in IITA Ibadan

Researchers at the International Institute of Tropical Agriculture (IITA) have successfully grown seed yams in the air using aeroponics technology, raising hopes and more options for the propagation of virus- and disease-free planting materials.

In preliminary trials, Dr Norbert Maroya, Project Manager for the Bill and Melinda Gates Foundation-funded “Yam Improvement for Incomes and Food Security in West Africa (YIIFSWA) project at IITA, together with a team of scientists successfully propagated yam by directly planting vine cuttings in Aeroponics System (AS) boxes to produce mini-tubers in the air.

Aeroponics System is the process of growing plants in an air or mist environment without the use of soil or an aggregate medium. The technology is widely used by commercial potato seed producers in eastern Africa (Kenya, Uganda, Tanzania etc.), and southern Africa (Mozambique, Malawi etc.) but successfully growing yam on aeroponics is a novelty for rapidly multiplying the much needed clean seed yam tubers in large quantities.

“With this approach we are optimistic that farmers will begin to have clean seed yams for better harvest,” Dr Maroya said on Friday.

Preliminary results showed that vine rooting in Aeroponics System had at least 95% success rate compared to vine rooting in carbonized rice husk with a maximum rate of 70%. Rooting time was much shorter in aeroponics.

Aeroponics is coming at an opportune time for African farmers. Traditionally, seed yam production is expensive and inefficient. Farmers save about 25 to 30% of their harvest for planting the same area in the following season, meaning less money in their pockets.

Moreover, these saved seeds are often infested with pathogens that significantly reduce farmers’ yield year after year.

However with an established Aeroponics System for seed yam propagation at the premises of an interested private investor, seed company or humanitarian nongovernmental organization; yam producers can have access to clean seed yams.

The soilless yam propagation system will increase the productivity of seed and ware yam and effectively reduce diseases and pests incidence and severity (no soil borne or vector-transmitted pests and diseases during the vegetative phase).

Dr Robert Asiedu, IITA Director for Western Africa described the results as “impressive.”

“Yam is an important crop in Africa and addressing the seeds’ constraint will go a long way in improving the livelihoods of farmers who depend on the crop for their livelihood,” he added.

In conducting the aeroponics trial, a special structure was built in an existing screen house with Dixon shelf frames using perforated styrofoam box, as support for plant vines, while the developing roots of the plants in the air were enclosed in conditions of total darkness to simulate the situation of soil to the roots. For the plant and tuber to develop, an automated power house system was established for atomizing periodically nutrient enriched water solution in the form of mist to feed the plants.