Identification of tightly linked SSR markers for flower type in carnation (Dianthus caryophyllus L.)

Single or double flower type is one of the most important breeding targets in carnation (Dianthus caryophyllus L.). We mapped the D (85) locus, which controls flower type, to LG 85P_15-2 using a simple sequence repeat (SSR)-based genetic linkage map constructed using 91 F-2 progeny derived from a cross between line 85-11 (double flower) and 'Pretty Favvare' (single flower). A positional comparison using SSR markers as anchor loci revealed that the map positions of the D (85) locus corresponded to the single locus controlling the single flower type derived from wild D. capitatus ssp. andrzejowskianus. We identified four co-segregating SSR markers on the D (85) locus. Verification of the SSR markers in commercial cultivars revealed that two of the four SSR markers (CES0212 and CES1982) were tightly linked to the D (85) locus, and amplified a 176-bp and 269-bp allele, respectively, which were common and unique to double flower cultivars. The map positions of the D (85) locus and the tightly linked SSR markers will be useful for determining the genetic basis of flower type and for marker-assisted breeding of carnations.