Chromosome numbers and meiotic behavior of some Paspalum accessions

Abstract

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.

Cytogenetic data for Paspalum notatum Flügge accessions

“…One accession presented a predominance of cells with just bivalents (MoraesFernandes et al, 1973). Variability in chromosome configurations in other Paspalum species have been reported by other authors such as Moraes-Fernandes et al (1968), Pagliarini et al (2001) and Adamowski et al (2005).…”

Determination of the mode of reproduction of bahiagrass hybrids using cytoembryological analysis and molecular markers

“…In the genus Paspalum, there is a close correlation between ploidy level and mode of reproduction, in which diploidy is correlated with sexual reproduction and outcrossing and polyploidy is correlated with apomixis (Adamowski et al, 2005).…”

Variabilidade genética de caracteres forrageiros em Paspalum

“…2012 há troca de alelos favoráveis à adaptação. Este fato aumenta os riscos de perda de genótipos por fatores abióticos e bióticos (Adamowski et al, 2005). Porém, a utilização de hibridizações, quando um dos genitores apresenta reprodução sexuada, pode gerar variabilidade e possibilitar a seleção de progênies elite, com fixação imediata dos caracteres de interesse em razão da apomixia (Rodrigues et al, 2003;Acuña et al, 2009).…”