QTL analysis for flowering time in carnation (Dianthus caryophyllus L.)

•The first report of QTL analysis for flowering time in carnation.•Identification of one major common QTL for flowering time despite the different populations and different years.•Developing a tightly linked DNA marker for distinguishing the flowering time. Flowering time is one of the most important traits in carnation (Dianthus caryophyllus L.) breeding because it decides the yearly yield. Two previously developed mapping populations were used to determine the number and effect of quantitative trait loci (QTLs) for flowering time. Flowering time showed large phenotypic segregation in two F2 populations and in different years. Despite the different populations and different years, one major common QTL for flowering time was detected in linkage group 10 with the effect explaining from 18.2%–22.5% of the overall phenotypic variance. We developed a DNA marker, qD1Flw1-sc43-4, that was located close to the detected QTL for flowering time. We could distinguish the flowering time and categorize the genotypes of an F1 population derived from a cross between late flowering ‘Light Pink Barbara’ and early flowering ‘Kaneainou 1 go’ using the qD1Flw1-sc43-4 marker. Our results suggest that flowering time in carnation involves several genetic factors. In this study, we identified one of the major factors for flowering time and developed a DNA marker that was tightly linked to the major QTL.