Breeding and selection of ryegrasses has produced plants with improved qualities. The grass on the left on the left is a hybrid that has been produced by crossing the standard ryegrass (Lolium perenne) with the annual ryegrass (Lolium multiflorum). It has four sets of chromosomes in each cell, which produces larger plants that grow better in the winter and early spring. This one is called Grasslands Greenstone.

The grass on the right is a perennial ryegrass (Lolium perenne) that has been especially bred as a turf grass for sports grounds. This is called Grasslands Coronet, and is a dwarf ryegrass with small leaves and the standard two sets of chromosomes per cell.