Breeding Value Of Base-Populations Derived From Contiguous Clusters In Perennial Ryegrass

Five broad-based breeding populations were produced by polycrossing natural populations sampled in five clusters developed by a hierarchical method with a geographic-contiguity constraint. As a result, each of these breeding populations originates from a single region and the populations within a cluster are more likely to share the same alleles with similar frequencies. A single generation of intercrossing would therefore be sufficient to establish a panmixia equilibrium.These populations were tested for dry-matter yield in plots and compared to control cultivars in two locations. There were some trends of specific adaptation related to the geographic origin of populations, which, on average, compared well to controls. Their half-sib families were evaluated as spaced plants in one location. This allowed genetic parameters and expected response to selection to be computed. Three out of five breeding populations appeared to be promising for the development of new, improved synthetic varieties.