Abstract
Improvement of quality and display life of miniature potted roses, Rosa hybrida L., is an important issue for rose breeders. Sensitivity to ethylene significantly influences the postproduction life of different cultivars. Availability of molecular markers that in the early growth stages can distinguish between rose cultivars with high or low ethylene sensitivity would therefore be valuable. Two tetraploid miniature potted cultivars, i.e., 'Vanilla' which is only slightly sensitive to ethylene and 'Lavender' which is very sensitive to ethylene, as well as four 'Vanilla' x 'Lavender' F1 progeny plants of low sensitivity and four of high sensitivity were investigated. The genes for the ethylene receptor RhETR3 and the transcription factor RhEIN3 were selected for development of cleaved amplified polymorphic sequence (CAPS) markers. Amplified fragments of RhETR3 and RhEIN3 cDNA of 'Vanilla' and 'Lavender' were cloned, sequenced and subjected to digestion with restriction enzymes with recognition sites containing SNPs detected by comparison of the sequences from 'Vanilla' and 'Lavender'. Two slightly different alleles of each gene were identified for both 'Vanilla' and 'Lavender'. The SNPs located in restriction enzyme sites lead to the expected differences in restriction fragment sizes between 'Vanilla' and 'Lavender' cDNAs, but the results for the F1 progeny plants are not correlated with their ethylene sensitivity. Since the plants are tetraploid, characterization of more alleles of the RhETR3 and RhEIN3 genes and more SNPs may be required to obtain a useful system of markers.