LAMP testing paves the way for improved virus diagnostics in cassava and sweetpotato seed in Tanzania

Cassava and sweetpotato play a vital role in food security and income generation in Tanzania. However, yields for these crops range far below their potential due to viruses that proliferate through seed.

Sweet potato virus disease (SPVD) and sweet potato chlorotic stunt virus (SPCSV) are the two most potent challenges to improving sweetpotato production in sub-Saharan Africa. Cassava crops, meanwhile, are hampered by cassava brown streak disease (CBSD).

While government-regulated clean seed programs in Tanzania are improving farmer access to virus-free planting material, early detection and diagnosis of disease in sweetpotato and cassava remains a vital tool for helping farmers boost current production levels.

However, current virus diagnostic tests are either not sensitive enough or require expensive laboratory equipment that calls for a high level of experience to operate properly. To address this challenge, scientists have begun using loop-mediated isothermal amplification (LAMP) tools to diagnose cassava and sweetpotato viruses. The technology is rising in popularity for its time efficiency and cost effectiveness. LAMP can be used directly in the field, making it ideal for ensuring seed quality within regulations set by the government.

In collaboration with the International Institute for Tropical Agriculture (IITA), the International Potato Center is working with seed regulators in the Tanzania Official Seed Certification Institute (TOSCI) to build their capacity to use LAMP to inspect sweetpotato and cassava seed throughout the country. Early trainings in this project have focused on harmonizing the testing procedures between the two crops with valuable assistance from Integrated Seed Sector Development (ISSD) Africa, the Sweetpotato Genetic Advances and Innovative Seed Systems (SweetGAINS) project and the Building an Economically-Sustainable Seed System in Tanzania for Cassava (BEST) project. In April 2021, key staff from CIP and IITA attended “trainer of trainers” courses conducted by Bramwel Wanjala of the Kenya Agricultural and Livestock Research Organization (KALRO).

Veneranda Ngazi from IIAT loads samples into a Genie II LAMP machine during an on-site virus testing in Dar es Salaam, Tanzania in April 2021. (photo: K. Ogero/CIP)

The trained staff then conducted a training for 11 TOSCI pathology staff in September 2021. These TOSCI staff will help share and cascade the knowledge gained to their colleagues in Morogoro, Mwanza, Mtwara, and Njombe zonal offices, therefore contributing to decentralization of the technology. IITA donated one LAMP machine for use at TOSCI headquarters.

Participants in the LAMP training held at TOSCI headquarters in September 2021. (photo: K. Ogero/CIP)

Overall, the added skills and capacity will enable the Tanzanian government to enhance the quality of its seed systems for sweetpotato and cassava while lowering the administrative costs for future seed businesses to earn certification for seed production. Together, these effects will enable higher yields for farmers and improved nutrition for consumers. 

Veneranda Ngazi of IITA hands over a LAMP machine to Salehe Kombo of TOSCI. The LAMP machine will enable more timely and effective diagnosis of viruses that affect sweetpotato and cassava yields (photo: K. Ogero/CIP)S