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Research article2011Peer reviewed

QTL mapping of resistance to leaf rust in Salix

Samils, Berit; Rönnberg Wästljung, Ann-Christin; Stenlid, Jan

Abstract

Genetic mapping of quantitative trait loci (QTL) for resistance to Melampsora leaf rust was performed in two willow families: the progeny from a backcross between Salix viminalis and a hybrid S. viminalis x Salix schwerinii (population S(1)), and the F(1) progeny of a cross between two S. viminalis (population S(3)). Disease levels were scored in the field for three consecutive years. In the laboratory, five different rust strains were sprayed onto leaf disks and the following resistance components were scored: latent period, diameter and number of uredinia, and flecking. One major QTL and 14 smaller were identified in the S(1) host population. One rust strain, that represents a Melampsora form with limited incidence on S. viminalis, showed lower aggressiveness to the S(1) host population together with a different pattern in QTLs. In the S(3) host population, we detected 13 QTLs for rust resistance, of which two were located to the same genomic regions as those found for the S(1) population. We showed that the strongest QTL co-segregated with a gene homologous to a known Toll/interleukin receptor-nucleotide binding site-leucine-rich repeat resistance gene in poplar. The importance of the identified QTLs is discussed in relation to breeding for durable resistance.

Keywords

Melampsora larici-epitea; Salix; Biomass willow; QTL mapping; Leaf rust resistance

Published in

Tree Genetics and Genomes
2011, Volume: 7, number: 6, pages: 1219-1235
Publisher: SPRINGER HEIDELBERG