Sweet potato is considered to be the third most important food crop in East Africa in terms of production and the fourth in Southern Africa.
It is an important source of income for small scale farmers who sell the root tubers for home consumption while vines are sold for animal feeds.
However, the crop just like other root crops grown in Uganda namely; cassava and yams, among others, are faced with the challenge of pests and diseases which has caused low yields.
This, therefore, has led to Agricultural Scientists and the National Crop Resources Research Institute (NaCRRI) in Namulonge to team up with development partners to breed improved varieties with resistance to pests.
One such collaboration is where scientists at NaCRRI running the root crop programme are collaborating with scientists at North Carolina’s State University College of Agriculture and Life Sciences (CALS) in conducting research using conventional methods to breed sweet potato varieties resistant to pests and diseases.
This collaboration will be extended to Makerere University College of Agriculture and Environmental Sciences where selected students will participate in the breeding programmme in a project which will run for four years.
North Carolina’s State University and College of Agriculture and Life Sciences (CALS) is the second largest college in the university in US and one of the largest colleges of its kind in the country with nearly 6,000 students.
With headquarters in Raleigh, North Carolina, the college includes 20 academic departments, the North Carolina Agricultural Research Service and the North Carolina Cooperative Extension Service among others.
The college dean Dr. Richard Linton while giving the overview of the university activities to scientists at NaCRRI explained that research service is the State’s principal agency of agricultural and life sciences with close to 600 projects related to more than 70 agricultural commodities, including agribusinesses and life science industries.
Scientists work not only on the college campus in Raleigh but also at various agricultural research stations and different field laboratories across North Carolina State.
Some of the subjects taught at the Plant for Human Health Institute are covered under different faculties which include faculty of horticultural science; food, bioprocessing and nutrition sciences; plant biology; genetics and agricultural and resource economics.
The college’s main aim is to address challenges of emerging pests and diseases farmers in the US and other parts of the world including Uganda, where issues of water efficiency, climate change as well as food security are faced.
The State according to Dr Linton manages $76 billion (Shs270 trillion) economy representing 16 percent of the economy in USA, which has created more than 663,000 jobs for people in the agricultural sector.
Giving the statistics of the agriculture activities in the university, he said, the college works in collaboration with companies dealing in bioscience products totalling to 520 within North Carolina.
The college has the extension outreach component where extension workers reach out to farming communities to teach them about good agronomy practices and other benefits related to agriculture.
Collaborations paying off
Regarding external collaboration, the university is in position to support 90 percent of international programmes including what is going on at NaCRRI. In Central America there exists the challenge of black sigatoka affecting banana species and in Europe scientists are breeding wheat varieties resistant to UG 99.
Dr Creg Yencho, the programme leader in sweet potato breeding at the University explains that the challenges scientists are faced with in the agricultural sector in North Carolina are the same scientists in Africa and Uganda are addressing and as such, the university is doing its best in providing scholarships for graduate students in Uganda and other parts of the world to help solve this problem.
Dr Benard Yada, a sweet potato breeder at NaCRRI one of the PHD students who benefited from this collaboration explains that the collaboration between North Carolina State University with Naro started way back in 1997 where they secured a donor agency called Mcknight Foundation who funded a breeding programme on orange fleshed sweet potato varieties at NaCRRI. This led to the release of Nasport 5 variety in the year 1997 and Naspot 8,9,12 and 13 which farmers accessed in 2013.
This programme led to training of Naro staff working in breeding sweet potato varieties mainly in the area of breeding and genetics where two scientists were given scholarships to study at the university.
Bill and Melinda Gates Foundation has come in to fund the current project called Genomic Tools for Sweet Potato improvement using modern ways of breeding where scientists are extracting DNA using conventional means in a bid to reduce the time framework from 10 previously to five years. Areas put in consideration are coming up with sweet potato varieties which are resistant to a weevil commonly found in Uganda called Cylas Puncticollis
Scientists working on this project at Kawanda have obtained sweet potato varieties from North Carolina State called Covington and Beauregand which are being crossed with the local varieties called New Kawogo and Tanzania.
According to Dr Yada, crosses have already been made and the team is evaluating the response in order to select varieties which are resistant to the weevil.
The breeding process started last year and the team has taken samples to multi locational trials to Abi Zonal Agricultural Research Development Institute (Abi Zardi) based in Arua, Bulindi Zonal Agricultural Research Development Institute in Hoima, Rwebitaba Zonal Agricultural Research Development Institute in Fort Portal and the National Semi-Arid Resources Research Institute (NaSARRI in Serere to evaluate how the crop will adopt to the different geographical locations.
Other partners supporting the current project are the International Potato Centre based in Peru, Michigan State University in the USA and University of Queensland in Australia.
It is a project worth $12.5m which will be implemented in four years with end results of releasing resistant varieties to farmers engaged in growing sweet potato.
According to Dr Yada, the sweet potato weevil is a big challenge to farmers growing the crop because once it infests a field, it is capable of causing 100 per cent loss because all the tubers can be rotten.
In the evaluation process scientists uproot clean tubers which are placed in plastic containers infested with the weevils. With its leads sealed, it is put aside for about three months.
A collection of 230 sweet potato varieties from weevil hot spot districts in Uganda have been collected for this study where crosses are made mainly from the flower to get those that are resistant.