Hybridization of AA genome rice species from Asia and Australia II. Meiotic analysis of Oryza meridionalis and its hybrids

Abstract

To determine the genomic constitution of Oryza meridionalis Ng (2n=2x=24) and to estimate genomic affinity between Asian and Australian wild species of rice containing the AA genomes, chromosome pairing was analyzed at metaphase I in O. meridionalis, O. rufipogon Griff. (2n=2x=24), O. nivara Sharma et Shastry (2n=2x=24), O. sativa f. spontanea Rosch, and their artifical hybrids. The Oryza parental species and their F1 hybrids showed normal meiosis, but slightly reduced chiasma fequency was observed in the hybrids. It is concluded from the cytological analysis that (i) the Australian O. meridionalis contains the AA genome which has very high affinity to that in the Asian AA genome wild species of rice; (ii) chromosome structual changes, such as inversions and reciprocal translocations, have occurred in the genomes of the different species studied.