The range of variability was examined for 8 generative traits of 62 perennial ryegrass strains. These strains were selected from 4 Polish breeding centres. Field experiment began in 2000 was completed in 2002. Very great variability of the most traits was observed, especially for the following traits: number of inflorescences per plant, fertility of spike, number of seeds per inflorescence and a thousand seed weight. Some of the above mentioned traits were connected with the maturity of plants. For example, early matured strains had shorter inflorescence, less number of panicles per inflorescence and smaller seeds. Forms of medium - early maturity - in contrast - had the longest inflorescence, the biggest weight of the thousand seeds, the density of spike and seed weight per inflorescence and per plant. Eleven strains of the highest fertility traits significantly correlated with the seed yield (inflorescence number per plant, spike fertility, seed weight per inflorescence) were selected from the whole population. These strains may be considered as the generative carriers of desirable traits for breeding new perennial ryegrass cultivars.