Lolium perenne L. (Lp) is one of the most important and valuable forage plants in grasslands and an indispensable component of seed mixtures for meadows, pastures, ley farming, and re-seeding measures. A set of 39 different cultivars of Lp assigned to early, intermediate, and late maturing types were harvested and analyzed in weekly intervals during the first growth at AREC Raumberg-Gumpenstein, Austria. Significant differences between the heading groups were found with a time lag of 6 days for crude protein content and of up to 11 days for digestibility of organic matter and energy concentration. The early heading cultivars significantly differed from the other two groups, which performed comparably and were more resilient in terms of quality aspects for a longer time. Within all three heading groups, a strong variation could be noticed, leading to some unexpected overlapping. Our results indicate that the current assignment of Lp cultivars to the heading groups is imprecise and should be improved by advanced recordings and by analyses during the time of the official variety testing period. This may lead to a more sufficient selection of Lp cultivars for grassland mixtures, and therefore, increase the quality of home-grown forage.
