DLF-TRIFOLIUM markets over 350 varieties worldwide. Before a new variety can be marketed, laws in most countries require that each variety be included on a list of approved varieties. Only the varieties that pass both the DUS and VALUE tests can be included on this list.In the value test, the varieties seeking approval are sown together with ones that have already been approved. Quality and yield (for forage grass and clover) are compared over a period of 2-4 years, during which time the candidates must demonstrate that they are better than the existing varieties.The candidates also undergo a DUS test. DUS stands for Distinctiveness, Uniformity and Stability. Comparisons of the size and color of various plant parts, ensure that the candidates can be separated from existing varieties. The properties investigated are governed by the international UPOV agreement.A national listing of varieties is typically valid for 10 years, and it can be extended if the variety possesses special qualities or has a very high turnover. When a variety has achieved list status in one EU country, it can be transferred to a common EU list of varieties, and can then be sold throughout the EU.