Abstract:
Coffee Berry Disease which caused by Colletotrichum kahawae, is a major constraint to the
cultivation of African Arabica coffee. In Ethiopia, it alone caused about a 24-30% loss of the
national average yield on local landraces. Ethiopia mainly uses resistant varieties and
mechanical and cultural disease management strategies. However, still, there is a lack of
improved and resistant varieties development in a few coffee growing areas including Arsi Zone.
The objectives of this study were to investigate the resistance of Arsi coffee collections to Coffee
Berry Disease through artificial inoculation of green berries on mother trees, younger coffee
seedlings under controlled conditions, and detached berries under laboratory conditions. The
field experiment was conducted at “Gololcha Arbagugu” farm state and Mechara Agricultural
research center on station. A hypocotyl test and detached berry test were conducted at Jimma
Agricultural Research Center and Haramaya University respectively. Field and detached berry
inoculation tests were carried out on 13 Arsi coffee collections and the Coffee Berry Disease -
susceptible Arusa coffee variety. Standard checks like susceptible variety (370) and resistant
varieties 741 and 754 were used for hypocotyl tests. Seventeen treatments were used for
hypocotyl tests. There was a significant difference in Coffee Berry Disease reaction levels among
genotypes (P< 0.001) under field conditions. The infection percentage of berries varied from
2.89 to 25.93% at Arsi and 3.25 to 34.92 % at Mechara three weeks after treatment applications.
The results of this study revealed highly significant (P < 0.001) differences in the percentage of
coffee berry disease infection among treatments in the detached berry inoculation test.
According to the results, the resistant variety 741 showed the lowest infection percentage (15.04
%) in comparison to all other collections and/or varieties at the seedling stage. Therefore, coffee
collections that showed the lowest level of infection percentage under all experimental
conditions (Ar15/11, Ar05/11, and Ar70/11) were recommended for further breeding strategies.
