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Research article2008Peer reviewed

Resistance to Melampsora larici-epitea leaf rust in Salix: analyses of quantitative trait loci

Ronnberg-Wastljung, Ann-Christin; Samils, Berit; Tsarouhas, Vasilios; Gullberg, Urban


Quantitative resistance of Salix to Melampsora larici--epitea leaf rust was studied in 2 Salix mapping populations. One population was a backcross between a S, schwerinii x S. viminalis hybrid and S. viminalis, and the other was all F(2) population between S. viminalis and S. dasyclados. A leaf disc bioassay was used to study the components of quantitative resistance (latent period, uredinia number, and uredinia size) to 3 isolates of the leaf rust. The analysis of quantitative trait loci (QTLs) revealed 9 genomic regions in the backcross population and 7 genomic regions in the F(2) population that were important for rust resistance, with QTLs explaining 8-26% of the phenotypic variation. An important genomic region was identified for the backcross population in linkage group 2, where QTLs were identified for all resistance components for 2 of the rust isolates. Four of the QTLs had overlapping mapping intervals, demonstrating a common genetic background for latent period, uredinia diameter, and uredinia number. QTLs specific to some rust isolates and to some resistance components were also found, indicating a combination of common and specific mechanisms involved in the various resistance components. Breeding implications in relation to these findings are discussed.


leaf disc inoculation; Melampsora larici-epitea; QTL mapping; quantitative resistance; Salix dasyclados; Salix schwerinii; Salix viminalis

Published in

Journal of Applied Genetics
2008, Volume: 49, number: 4, pages: 321-331