Development of a long term strategy based on genetic resistance and agroecological approaches against coffee wilt disease in Africa : fifth annual report covering period 1/11/2005 to 31/10/2006

Coffee wilt disease is the main constraint of Robusta coffee growing in the countries participating in the project. It is continuing to spread towards Equator province in DRC and is killing new coffee trees in Uganda in regions already affected. In Tanzania, CWD has affected new districts despite the proposed preventive measures, grubbing up and burning coffee trees displaying the first symptoms. In Ethiopia, the disease on C. arabica seems to be spreading and there are grounds for fearing that the genetic resources conserved at Jima could disappear. The seriousness and threat of CWD for coffee growing are real. Preventive measures developed recently in Tanzania, or at the outset of the epidemic in Uganda, do not seem to be enough to stop the disease from spreading. Variety resistance is considered the best option for an effective control of the coffee wilt disease and therefore the main objective of this project remains, to develop a global strategy to fighting the disease, based on durable tolerance/resistance, that is adapted to small holder agro-system and to the economic conditions prevailing in Africa. In year 5, the work carried out built on results obtained in year 4. i.e: 1- Study the speciation of Fusarium xylarioides within the African Coffee wilt disease. 2- Assess the aggressiveness of isolates and characterize interactions. 3- Identify coffee trees bearing resistance factors and analyse inheritance of resistance to CWD. 4- Analysis of genetic diversity of Coffea canephora from Uganda and DRC. 5- Analysis of spatial and temporal spread of the CWD in the field. 6- Assess correlations between field resistance and artificial inoculation tests. (Résumé d'auteur