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Quantitative Trait Loci Analysis of Resistance to Sclerotinia sclerotiorum in Sunflower

July 2005 , Volume 95 , Number  7
Pages  834 - 839

S. Rönicke , V. Hahn , A. Vogler , and W. Friedt

First, third, and fourth authors: Institute for Crop Science and Plant Breeding, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany; and second author: State Plant Breeding Institute, University of Hohenheim, D-70593 Stuttgart, Germany

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Accepted for publication 2 March 2005.

A quantitative trait loci (QTL) analysis of resistance to Sclerotinia sclerotiorum was carried out with 283 sunflower (Helianthus annuus) F2:3 families derived from a cross between a resistant (SWS-B-04) and a highly susceptible sunflower inbred line. For that purpose, a genetic map based on 195 amplified fragment length polymorphism and 20 simple sequence repeat markers was constructed. The map has a size of 2,273.5 centimorgans and comprises 17 linkage groups, 12 of which could be associated to already defined linkage groups. The heads of sunflower F3 families were artificially inoculated by using sclerotinia mycelium in three field environments. The lesion length was measured in centimeters 1 week postinoculation and head rot was scored according to a 1-to-8 head rot scale 2 weeks postinoculation. Using the composite interval mapping procedure, three QTL for lesion length and two QTL for head rot could be identified. These QTL explain 10.6 to 17.1% of the total phenotypic variance.

© 2005 The American Phytopathological Society