Time series of the genetic diversity of perennial ryegrass swards.

Genetic diversity of the 14 field plots as estimated by mean He, based on 22,324 SNPs (A), and time series of mean AAFpool per sample, based on 246 Merks private SNPs (B) and 617 Meloni private SNPs (C). Lines represent the time series of a field plot, and the colors indicate the seed composition. The genetic diversity of field plots with seed compositions containing Merks only (1 and 3) remained stable throughout the four years. The field plots of seed compositions containing Meloni only (2 and 4) were less diverse than those of Merks, but increased slightly after establishment. The field plots containing both cultivars (5 to 7) were more diverse and more variable than the plots containing a single cultivar. These changes coincide with changes in the mean AAFpool of cultivar private SNPs, and are attributed to shifts in the cultivar composition of the population.