b'First, the mixture needs to be a blend of species that will establish quickly and form a dense and well rooted matt, says Dahl Jensen. And creeping grasses, like creeping red fescues and smooth-stalked meadow grass are very effective in this way. The grasses then need to be both fine and dense in appearance, with excellent natural disease resistance which reduces pro-duction costs and maintenance costs for the end user, she adds.The two grass species, perennial ryegrass and smooth-stalked meadow-grass, are very commonly used for heavy duty sports fields. This is due to the unique wear tolerance they both present and to the self-repair strength of especially smooth-stalked meadow grass. The slower establishment of the smooth-stalked meadow grass is outweighed by the fast-establishing perennial ryegrass.Van der Weijde adds that in their sports grass breeding pro-grammes, the most important features are wear tolerance, a quick and even germination, sod density and disease resistance.Grass selection trials. Source: DSV Dahl Jensen adds that once all criteria have been met, it is critical that the seed lots are pure and free from coarse grasses and aggressive weeds. Once a coarse grass has established in the field, its almost impossible to remove it from the turf with-out very expensive intervention. Therefore, the quality of the seed production is crucial. In our company, the seed production of high-quality turf varieties is carried out with an integrated approach and an end-to-end control to obtain the highest qualitylabelled DLF Select, she says. Very few clubs use turf for stadia these days, as natural grass seed establishes very fast and most of the high-end stadia use a hybrid pitch system which means they cant be turfed. For fast establishment in combination with a hybrid turf solution, a mixture of turf perennial ryegrasses, often five to six different varieties, will be a fine choice, says Dahl Jensen. Multi-function stadia that are used for sports and different events like concerts may need to replace their turf several times during the season. In that case, 4 cm thick magnum turf-rolls can be installed and made playable in a short time frame. OVERSEEDINGCertain turf grass varieties are selected specifically for overseed-ing, which is especially important for stadia and sod producers. According to Dahl Jensen, it would depend on when you are overseeding. For example, if it was for end of season renovation, it would be wear tolerance, disease resistance, drought tolerance and colour. But if you are doing in-season overseeding, then speed of establishment would be a bigger factor, although all diploid turf perennial ryegrass cultivars are fast to germinate. The larger seeded 4turf tetraploid perennial ryegrasses and our turf annual ryegrasses are able to germinate very fast at low temperatures, and they can be used when soil temperatures are less optimal in the autumn and spring months, she adds.Rose-Fricker mentions that the varieties they select for overseeding should have a high purity and germination, rapid establishment and a good colour. But also, high density and wear tolerance are equally important. The fact that many stadia now have light rigs and under-soil heating makes germination less of a worry. So, breeders are back to wear tolerance, disease resistance and colour as primary fea-tures. This is a significant reason that grounds managers have taken the new 4turf varieties onboard, as this type of perennial ryegrass is in a special league when it comes to stress tolerance A wear machine, mimicking soccer shoe studs. Source: DLF and disease resistance and thus have lesser need for fungicide usage says Dahl Jensen.8IEUROPEAN SEEDIEUROPEAN-SEED.COM'