The objective of this study was to investigate components of production and seed production of two Paspalum species. It was evaluated two ecotypes of Paspalum notatum and Bagual) and two ecotypes of Paspalm urvillei (André da Rocha and Eldorado do Sul). It was used a complete randomized experimental design, in a factorial scheme (ecotypes × days after planting), with five replicates nested within days after planting. Each species was analyzed separately for determination of the components of production and seed production. The variables were measured weekly from November 7th 2006 to March 31st 2007. The following variables were evaluated: number of vegetative tillers, number of reproductive tillers/m2, percentage of fertile tillers, number of racemes/m2, weight of 1000 seeds, number of seeds/inflorescence, number of seeds/raceme and seed yield per area. Seed production of Paspalum is negatively affected by the long flowering period and by the capacity of retention by the seeds in the inflorescence. Seed production differs among ecotypes inasmuch as mean values were 47.17 kg/ha (Paspalum notatum André da Rocha), 61.01 kg/ha (Paspalum notatum Bagual), 30.60 kg/ha (Paspalm urvillei André da Rocha) and 47.95 kg/ha (Paspalm urvillei Eldorado do Sul). Seed production of those species is highly affected by the number of reproductive tillers, by the percentage of fertile tillers and by the weight of 1000 seeds.
