Genetic linkage mapping in tetraploid and diploid rose

Roses (Rosa species) are among the most important ornamental plants. Though widely grown in gardens worldwide and of great economic significance, little is known about rose genetics and genomics. Understanding how important traits are inherited in roses, and developing genetic linkage maps locating the genes controlling the traits can greatly accelerate the production of superior rose germplasm. In this research, the inheritance of floral traits, other morphological traits and resistance to two diseases were studied in diploid R. multiflora. In addition, four genetic linkage maps were constructed for tetraploid R. hybrids and diploid R. multiflora using amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers. Thirty new rose microsatellite markers were developed for mapping by screening a small-insert genomic library. Based on the common SSR markers among the maps, a preliminary consensus map for the rose genome was generated.; Two linkage maps were generated from a hybrid tetraploid F2 progeny that has at least four species, R. wichuraiana, R. rugosa, R. carolina and R. virginiana, in its background. The two maps constructed for parents 82-1134 (having R. carolina and R. virginiana in the background) and 86-7 (having R. wichuraiana and R. rugosa in the background) consist of 20 and 14 linkage covering 920 cM and 770 cM, respectively. Two loci controlling presence of prickles on the petiole (Ppr) and malate dehydrogenase subunit 2 (Mdh-2) were located on the 86-7 map. Two additional maps were developed from a diploid intraspecific R. multiflora family. Two maps constructed for parents 95/13-39 and Spalier-3 consist of 7 linkage groups each and cover 360 cM and 376 cM, respectively. In the diploid family, inheritance of single vs. multiple corolla, number of petals/flower, flower color, repeat blooming, leaf size, presence and size of prickles, resistance to powdery mildew (both qualitative and quantitative) and resistance to black spot (qualitative) were studied. Double corolla (Dc), repeat blooming (Rb), and resistance to black spot (Rbs ) were found to have simple inheritance, and they were located on the diploid maps. Number of petals/flower, flower color, leaf size, prickle size and resistance to powdery mildew were found to have complex inheritance. Thirteen quantitative trait loci (QTL) (at LOD > 3.0) controlling these complex traits were located on the maps. Inheritance of prickles on the stem was not conclusively determined and not mapped. (Abstract shortened by UMI.)...