Exchanging and managing in-vitro elite germplasm to combat Cassava Brown Streak Disease (CBSD) and Cassava Mosaic Disease (CMD) in Eastern and Southern Africa
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Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
Food Security
Abstract
Cassava varieties resistant to cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) are needed for the food
and income security of the rural poor in eastern and southern Africa (ESA). The International Institute of Tropical Agriculture led
five national cassava breeding programs (Malawi, Mozambique, Kenya, Tanzania and Uganda) in virus-cleaning and exchanging
elite cassava germplasm resistant to both diseases. This paper documents the experiences and lessons learned from the process.
Thirty-one clones (25 elite, two standard and four national) were submitted by the five breeding programs to the Natural
Resources Institute and Kenya Plant Health Inspectorate Services for virus cleaning and indexing. Subsequently, ca 75 invitro
virus-indexed plantlets per clone were sent to Genetic Technologies International Limited (GTIL), a private tissue culture
(TC) lab in Kenya, and micro-propagated to produce ≥1500 plantlets. After fulfilling all the formal procedures of germplasm
exchange between countries ≥300 plantlets per clone were sent to each partner country. National check clones susceptible to
CMD/CBSD were sent only to their countries of origin. In each country, the in-vitro plantlets were acclimatized under screen
house conditions and transferred to clean isolated sites for field multiplication. All the clones were cleaned of the viruses, except
Tomo. The cleaning process was slow for F19-NL, NASE1, and Kibandameno and TC micro-propagation at GTIL was less
efficient for Pwani, Tajirika, NASE1, and Okhumelela than for the other clones. Difficulties in cleaning recalcitrant clones
affected the timeline for establishing the multi-site evaluation trials in target countries. The initiative is the one of the kind to
successfully clean and exchange elite germplasm as a joint action to combat CBSD in ESA. Adequate preparation in terms of
infrastructure and personnel are critical to successfully receiving and adapting the indexed in-vitro plants as new germplasm.
Description
Keywords
Exchange, In-vitro, Germplasm, CBSD, CMD
Citation
Tumwegamire, S., Kanju, E., Legg, J., Shirima, R., Kombo, S., Mkamilo, G., ... & Mark, D. (2018). Exchanging and managing in-vitro elite germplasm to combat Cassava Brown Streak Disease (CBSD) and Cassava Mosaic Disease (CMD) in Eastern and Southern Africa. Food Security, 10(2), 351-368. https://doi.org/10.1007/s12571-018-0779-2