Chromosome number and meiotic behavior were evaluated in 36 Brazilian accessions of the grass Paspalum (which had never previously been analyzed) to determinate which accessions might be useful in interspecific hybridizations. The analysis showed that one accession of Paspalum coryphaeum was diploid (2n = 2x = 20) and one accession of Paspalum conspersum hexaploid (2n = 6x = 60), the remaining 34 accessions being tetraploid (2n = 4x = 40). The pairing configuration was typical for the ploidy level i.e. in the diploid, chromosomes paired as 10 bivalents, in tetraploids as bi-, tri- and quadrivalents, and in hexaploid as 30 bivalents. A low frequency of meiotic abnormalities (less than 10%) was observed in the diploid, hexaploid and some tetraploid accessions, although the majority of tetraploid accessions showed a high frequency of meiotic irregularities. The use of accessions with a low frequency of meiotic abnormalities in breeding programs is discussed.

Apesar da importância econômica do gênero Paspalum, pouca ou nenhuma informação citológica é encontrada para a maioria das espécies. Esta é a primeira descrição sobre número de cromossomos e comportamento meiótico para P. maritimum. Os três acessos coletados no Estado do Amapá mostraram-se tetraplóides (2n=4x=40) com os cromossomos associando-se predominantemente como bivalentes. A baixa ocorrência de associações multivalentes sugere que estes acessos sejam alotetraplóides segmentais. Todos os acessos mostraram uma baixa frequência de anormalidades meióticas e, como consequência, uma alta fertilidade de pólen, mostrando potencial para serem utilizados em programas de hibridização.

Despite of economic importance of the genus Paspalum, little or no cytologic information is available for many species. This is the first report about chromosome number and meiotic behavior for P. maritimum. The three accessions collected in Amapá State (North Region of Brazil) were tetraploid (2n=4x=40) with the chromosomes associating predominantly as bivalents. The low frequency of multivalents suggested that they were segmental allotetraploids. All accessions showed a low rate of meiotic irregularities, and as a consequence the pollen fertility was high. The results suggested that these accessions presented potential for use in a hybridization program.