Field Screening of Selected Coffea arabica L. Genotypes Against Coffee Leaf Rust

Coffee Leaf Rust (CLR) is a fungal disease caused by Hemileia vastatrix Berk et Br. and is one of the major diseases of coffee. It causes premature leaf fall, yield loss and even death of the tree in severe cases. Coffee genotypes respond differently to biotic factors. This study was aimed at identifying potential sources of resistance genes to the disease. Forty five Coffea arabica L accessions were evaluated for their response to CLR under field conditions. CLR infection was assessed from the 45 genotypes subjected to similar field conditions in June 2010 when disease pressure was at peak. The experimental plot was laid out in a Randomized Complete Block Design with three replications. Each of the genotypes was represented by fifteen trees consisting of five trees per replication. Significant variation in tolerance to CLR was observed among the genotypes and some tolerant genotypes identified. HDT, Rumesudan, Barbuk Sudan, Ennareta, Geisha12, Babbaka Ghimira, Boma plateau and Tafari Kela were the most tolerant to CLR (recording a score of 0) while Drought Resistant II [DRII]) was the most susceptible recording a score of 8. Most of the accessions that demonstrated high phenotypic resistance have not been utilized as sources of resistance to CLR in coffee breeding programmes except HDT. Such genotypes could represent a highly valuable resource for C. arabica breeding against CLR if their reaction is confirmed.