A tetraploid F 2 progeny segregating for resistance to black spot, growth habit, and absence of prickles on the stem and petioles was used to construct genetic linkage maps of rose. The F 1 of the progeny, 90-69, was created by crossing a black spot-resistant amphidiploid, 86-7, with a susceptible tetraploid, 82-1134. The F 1 was open-pollinated to obtain 115 seedlings. AFLP and SSR markers were used to eliminate seedlings produced through cross-fertilization. The remaining progeny set of 52 F 2 plants was used to study the inheritance of 675 AFLPs, one isozyme, three morphological and six SSR markers. AFLP markers were developed with three combinations of restriction enzymes, EcoRI/MseI, KpnI/MseI and PstI/MseI. Most of the markers appear to be in simplex or single-dose and segregated 3:1 in the progeny. One linkage map was constructed for each parent using only the single-dose markers. The map of 86-7 consists of 171 markers assigned to 15 linkage groups and covering more than 902 cM of the genome. The map of 82-1134 consists of 167 markers assigned to 14 linkage groups and covering more than 682 cM of the genome. In the AFLP analysis, EcoRI/MseI generated nearly twice as many markers per run than PstI/MseI. Markers developed with three restriction enzyme combinations showed a mixed distribution throughout the maps. A gene controlling the prickles on the petiole was located at the end of linkage group 7 on the map of 86-7. A gene for malate dehydrogenase locus 2 was located in the middle of linkage group 4 on the map of 86-7. These first-generation maps provide initial tools for markerassisted selection and gene introgression for the improvement of modern tetraploid roses.

No abstract

New microsatellites markers [simple sequence repeat (SSR)] have been isolated from rose and integrated into an existing amplified fragment-length polymorphism genetic map. This new map was used to identify quantitative trait locus (QTL) controlling date of flowering and number of petals. From a rose bud expressed sequence tag (EST) database of 2,556 unigenes and a rose genomic library, 44 EST-SSRs and 20 genomic-SSR markers were developed, respectively. These new rose SSRs were used to expand genetic maps of the rose interspecific F 1 progeny. In addition, SSRs from other Rosaceae genera were also tested in the mapping progeny. Genetic maps for the two parents of the progeny were constructed using pseudo-testcross mapping strategy. The maps consist of seven linkage groups of 105 markers covering 432 cM for the maternal map and 136 markers covering 438 cM for the paternal map. Homologous relationships among linkage groups between the maternal and paternal maps were established using SSR markers. Loci controlling flowering traits were localised on genetic maps as a major gene and QTL for the number of petals and a QTL for the blooming date. New SSR markers developed in this study will provide tools for the establishment of a consensus linkage map for roses that combine traits and markers in various rose genetic maps.

Damask roses are grown in several European and Asiatic countries for rose oil production. Twenty-six oil-bearing Rosa damascena Mill. accessions and 13 garden Damask roses were assayed by molecular markers. Microsatellite genotyping demonstrated that R. damascena Mill. accessions from Bulgaria, Iran, and India and old European Damask rose varieties possess identical microsatellite profiles, suggesting a common origin. At the same time, the data indicated that modern industrial oil rose cultivation is based on a very narrow genepool and that oil rose collections contain many genetically identical accessions. The study of long-term vegetative propagation of the Damask roses also reveals high somatic stability for the microsatellite loci analyzed.