Construction of a Genetic Linkage Map for the Carnation by Using RAPD and SSR Markers and Mapping Quantitative Trait Loci (QTL) for Resistance to Bacterial Wilt Caused by Burkholderia caryophylli

Abstract

We constructed a genetic linkage map for the carnation (Dianthus caryophyllus L.) on the basis of random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) by using a resistance-segregating population of 134 progeny lines that were derived from a cross between ‘Carnation Nou No. 1’ (a carnation breeding line resistant to bacterial wilt) and ‘Pretty Favvare’ (a susceptible cultivar). The linkage map consisted of 137 RAPD and 9 SSR markers. Linkage analysis revealed that 124 loci could be mapped to 16 linkage groups that extended for 605.0 centiMorgans (cM). The average interval between two loci was 4.9 cM. Quantitative trait loci (QTL) analysis was applied to evaluations of resistance to bacterial wilt that were replicated 8 times. The QTL that we reported previously with a large effect on resistance was detected on group 6 which accounted for 60.5% of the total phenotypic variance with a LOD score 23.46. Two other QTLs with small effects were detected on groups 2 and 5 with LOD scores of 2.32 and 2.87, respectively. These results suggest that resistance to bacterial wilt in carnation is related to one major and at least two minor genes. This study is the first report on the construction of a linkage map of the carnation.