Prospects for achieving multiple disease resistance with Coffea canephora clones.

In the present work, it was phenotyped 29 Coffea canephora clones for resistance to Hemileia vastatrix races II and XXXIII and investigated the presence of molecular markers associated with Coffee Leaf Rust (CLR) and Coffee Berry Disease (CBD) resistance loci in 67 clones. Phenotyping for resistance was performed by evaluating six components of quantitative resistance using the leaf disc technique. The averages of the components were submitted to the Scott-Knott test and to the multivariate analysis to obtain the generalized Mahalanobis distance, which was used to group the clones by the unweighted pair-group method using arithmetic averages. In screening resistance to CLR, molecular markers were evaluated associated with two resistance loci. Three sequence characterized amplified regions (SCAR) and a simple sequence repeats (SSR) markers associated with the locus of S_H3 gene (Locus A); a SCAR and a cleaved amplified polymorphic site (CAPS) associated with a locus of resistance to races I, II and pathotype 001 of H. vastatrix (Locus B). For screening resistance to CBD, two SSRs were associated with the locus of the resistance Ck-1 gene (Locus C) were evaluated. The phenotyped clones were grouped into five resistance classes for each H. vastatrix race. Fifteen clones have locus of resistance to races I, II, and the pathotype 001 of H. vastatrix. Three clones have the Ck-1 gene. These results support growers to choose resistant clones for crop composition and indicate potential sources of CLR and CBD resistance for C. canephora breeding programs. [ABSTRACT FROM AUTHOR]