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An assessment of genetic improvement in turf-type perennial ryegrass was performed at a network of six locations. A comparison was made of the turf performances of five natural populations, five forage-type cultivars used for turf seeding until the 1980s and 31 turf-type cultivars released from 1974 to 2004. Populations and cultivars were also compared in two spaced-plant experiments and in two seed-yield trials. Trait regressions on registration year of turf-type cultivars showed that breeding had been highly successful in improving the turf aesthetic merit (from +8·8 to +12·5% per decade according to seasons), wear tolerance (+5·4% per decade) and crown-rust resistance (+8·9% per decade) and in lessening the turf height increase rate (−0·43 mm day−1 per decade). Turf winter greenness had been marginally improved, whereas summer greenness and seed yield had not been significantly changed. A multivariate analysis provided evidence that turf density and fineness played a major role in the visual assessment of turf aesthetic merit and that wear tolerance was closely associated with turf density. Conflicting trait associations may have precluded improvements in turf ground-cover 3 months after sowing, turf winter greenness and turf persistency. [ABSTRACT FROM AUTHOR]