Caractérisation d'écotypes de pâturin des prés selon le site de prélèvement

Characterization of meadow grass ecotypes according to collection sites

The improvement of meadow grass (Poa pratensis) by breeding should conciliate a good agricultural value and a satisfactory seed productivity. The collection of ecotypes in natural grassland remains an efficient and much-used method for the improvement of the species, but the collection sites must be chosen according to the desired traits of the plant material. A total of 640 vegetative genotypes of voluntary meadow grass plants were sampled in very diverse locations (altitude, type and intensity of management) in the Swiss canton of Vaud. The observation of populations and clones shows that there exists a very large genetic variation among voluntary plants and that it is possible to find plants of good agricultural value everywhere. Highly performing ecotypes are however more likely to be found at medium altitudes (450 to 650 m), on not too dry soils, and where meadow grass grows abundantly. Meadow grass plants from these sites conserve their vegetative aggressiveness in the lowlands and their forage value is good, but their seed-bearing capacity should be improved by breeding ; the seed productivity is indeed all the smaller as the genotype is later heading.