Towards Marker Assisted Breeding for Persistent Red Clover (Trifolium pratense L.).
Roland Kölliker, Doris Herrmann, Beat Boller, and Franco Widmer. Agroscope Reckenholz-Tänikon Research Station ART, Reckenholzstr. 191, Zurich, 8046, Switzerland
Red clover, one of the most important forage legumes of temperate grasslands, is often grown in multi-species mixtures for several years. Therefore, persistence is a key target in red clover breeding. In Switzerland, decades of on-farm seed production resulted in red clover landraces locally known as Mattenklee. Some of these Mattenklee landraces (MKL) were used for the development of highly persistent Mattenklee cultivars which are nowadays widely used in many European countries, but most of them disappeared. However, roughly one hundred MKL were conserved in a germplasm collection.Using AFLP markers, we were able to show that the remaining MKL form a distinct and highly diverse genetic resource of red clover. MKL were clearly separated from indigenous wild clover populations and from red clover cultivars. Despite the high distinctness of MKL, some showed close relationships to Mattenklee cultivars, highlighting their potential for introgression into breeding programs. Phenotypic characterization revealed considerable variation for persistence among the MKL investigated. While most MKL showed rather low persistence, some clearly exceeded persistence values observed in field clover cultivars and nearly reached values observed in Mattenklee cultivars. In order to develop molecular tools for the targeted introgression of persistence traits into breeding material, a mapping population based on a cross between one plant of the field clover cultivar Violetta (low persistence) and the Mattenklee cultivar Corvus (high persistence) was evaluated in the field for various traits including persistence. QTL analysis revealed one significant QTL on linkage group 3, which explained 10% of the variation observed for persistence. This QTL points to an interesting target region for the further development of molecular markers linked to persistence. Such markers, together with the strategy developed for the characterization of germplasm collections, may assist future breeding efforts for the improvement of persistence in red clover.