Scientists are pushing countries across sub-Saharan Africa to harmonise standards for sweet potato seed production, which they say is crucial in improving the quality, quantity and market access of the crop.
In East Africa, Kenya and Ethiopia have put such standards in place. Tanzania recently approved its regulations. The other countries are at different stages of the process.
The standards include ensuring that potato seed multipliers sell quality vine seedlings that are disease-free, and that they are of the right variety and quantity.
Margaret McEwan, a senior project manager for the sweet potato seed systems under the International Potato Centre (CIP), said the production of sweet potatoes on the continent has been hampered by virus diseases that affect the quality of vines used as planting material, and subsequently the amount of yields.
“The sweet potato seed system has been dealing with several challenges like virus diseases that have built up over time and affected yields,” said McEwan.
“With the improved, disease-resistant sweet potatoes, farmers can produce between 12 and 15 tonnes per hectare compared with four tonnes with the existing varieties.”
Dr Benard Yada, a potato breeder at the Uganda National Crop Sciences Research Institute Namulonge, said that over the past 10 years, there has been a growing demand to produce sweet potato seed as a business.
“Many NGOs have taken interest in buying sweet potato seeds from multipliers in large quantities for distribution and food security interventions. This therefore calls for checks and balances to ensure the quality of material that is being delivered to the growers is superior,” he said.
Dr Settumba Mukasa, a researcher at the school of agricultural sciences at Makerere University in Uganda, argues that as farmers move to growing sweet potatoes on a commercial basis, they need to get planting materials that are clean and disease-free in order to get value from the crop.
“This high value is what needs to be protected and we can only do that when we put standards in place,” said Dr Mukasa, adding that the university is currently working with Uganda’s Ministry of Agriculture to develop seed standards for the country.
According to the CIP, sweet potato is the third most important food crop in East and Central Africa after cassava and maize. It is also considered an easy crop to grow because it requires fewer inputs and less labour.
Dr Yada said the improved varieties are being promoted because of their additional value in ensuring food security and fighting childhood malnutrition.
One such variety is the orange flesh sweet potato, which is being promoted across the continent, especially in countries like Uganda and Mozambique, where Vitamin A deficiency affects 38 and 68 per cent of all children, respectively.
The orange flesh sweet potato is high in beta-carotene, a nutrient that the body can convert into vitamin.