Archive | 2019
Rosa arvensis as a possible genetic model
Abstract
Despite a long-range breeding tradition in Europe, the rose remains poorly investigated at the level of formal genetics. In particular, a genetic model is missing that uses the advantages of reliable advanced pedigree from a wild species, carrying precise genotype annotations for characters and documented data on the origin of the genetic variations. Diploid species are more suitable for developing and understanding classical genetics in roses, and such studies can be extrapolated to tetraploid garden roses. R. arvensis, a common hardy rose from the synstylae group, is the only one diploid species to be broadly distributed in Europe, but was never explored genetically. In the wild, R. arvensis has distinctive traits, with no or little variability at first glance. Nevertheless, I have sampled from several regions of France, more than 60 rare variants and founded an experimental and conservatory garden to investigate the species genetically. For this, I chose a wild-collected (1995) standard plant Osenbuhr as the reference genotype to start several complementary strategies of breeding programmes: controlled consanguineous and semi-compatible inbred lines, genetic exploration of the wild-collected variants, hybridization with mutants from other species, and finally hybridization of mutants accurately defined from the domesticated genetic pool. As the latter strains were chosen to recapitulate most of the diploid founders of the modern roses, a historic core-collection could be reconstituted with its own genealogy in the same time. The historical pedigree was anchored to the Osenbuhr pedigree through hybridization with the different pioneer cultivars and altogether the roughly 1000 accessions convey around 160 independent characters. After 20 years of investigations, I will discuss whether R. arvensis would be suitable as a genetic model to investigate specialized metabolisms in roses.