Evaluating Lowland Coffee Genotypes against Leaf Rust and Wilt Diseases in Southwestern Ethiopia

Hailu Negesa^1*Gabisa Gidisa¹Zenebe Wubshet¹Kifle Belachew¹Wakuma Merga²Desaleng Alamayo¹Lemi Beksisa¹Dawit Merga¹Mohammedsani Zakir¹

• ¹Jimma Agricultural Research Center, Ethiopian Institute of Agricultural Research (EIAR), Jimma, Ethiopia
• ²Teppi Agricultural Research Center, Ethiopian Institute of Agricultural Research, Teppi, Ethiopia, Teppi, Ethiopia

Coffee is one of the most economically essential agricultural commodities worldwide and in Ethiopia in Particular. Despite its importance, it is constrained by different factors. Among which, Ccoffee leaf rust, caused by Hemileia vastatrix and wilt disease, caused by Gibberella xylarioides are among the major limiting constraints factors of coffee production. However, Ethiopia has not yet been reported to havecommercialized resistant genotypesvariety for both of the diseases. Therefore, the present study was conducted to evaluate lowland coffee genotypes against coffee leaf rust and wilt disease under field and greenhouse conditions, respectively. A field experiment was conducted across four locations (Agaro, Teppi, Bebeka and Gelesha) during 2021 to 2023. A randomized complete block design with three replications was used. The experiment for wilt disease was conducted on thethrough seedlings, using seedling stem-nicking inoculation techniques inoculation under greenhouse conditions. The results revealed a significant difference among the genotypes in reaction tofor leaf rust and wilt diseases. Among the tested genotypes, I-1, I-2, K-1 and K-2 were consistently showed a highly resistant reaction to leaf rust throughout the locations, whereas one genotype (EB-1) indicated a susceptible reaction across the locations. From the genotypes the highest mean leaf rust severity was recorded on EB-1 (27.1%) while the lowest severity was recorded on I-2(0.35%) genotype.Similarly, four genotypes (I-1, I-2, K-1 and K-2) showed moderately resistancet reaction to wilt disease and also indicated an extended incubation period as compared to the susceptible control (Geisha). Analysis of GXE interaction also indicated, highly significant interaction (P < 0.01) of genotype by environment. Among climate factors, relative humidity and maximum temperature were showed highly significant and positive correlation with coffee leaf rust. Overall, theseThese resistant genotypes could be used by farmers as a component of integrated disease management around coffee leaf rust-prone areas of the country. In addition, end users have to integrate with other wilt management options to use these genotypes. Overall, these genotypes can enhance the resilience of coffee production by combining with other coffee leaf rust and wilt diseases management strategies across the lowland coffee production areas of Ethiopia.