Taxonomic status of Oryza glumaepatula Steud. III. Assessment of genomic affinity among AA genome species from the New World, Asia, and Australia uri icon

abstract

  • In order to assess affinity of the AA genome in different wild Oryza species from Asia, Australia, and South America, chromosome pairing was analyzed at metaphase-I of the F-1 hybrids obtained from interspecific crosses among O. rufipogon Griff., O. nivara Sharma et Shastry, O. glumaepatula Steud., and O. meridionalis Ng, and the hybrids produced between different populations of the same species. Both intraspecific and interspecific hybrids showed normal meiosis with remarkably high chromosome pairing at metaphase-I, which was comparable with the meiotic pairing of their respective parental species. An average of higher than 23 chiasmata per pollen mother cell (PMC) was observed in ail the intraspecific and interspecific hybrids, except for one O. glumaepatula x O. nivara hybrid which had an average of 22.6 chiasmata per PMC at metaphase-I. No other meiotic irregularities except for a few bridges and laggards were found in the hybrids. It is concluded from this cytological study that the AA genome is essentially identical in the four Oryza species, as well as in different populations of the same rice species. It is therefore not recommended to differentiate the genomic designation of AA genomes by adding superscripts for different species.

publication date

  • 1998
  • 1998