Abstract
Intergeneric hybrids involving Oryza punctata (2n=48, BBCC) with Leersia tisseranti (2n=24), O. punctata with L. perrieri (2n=24), O. latifolia (2n=48, CCDD) with L. tisseranti and O. latifolia with L. perrieri were produced at frequencies varying from 0.11% to 0.23% of the pollinated spikelets. Plant morphologies of the hybrids strongly resembled the tetraploid Oryza species. Five hybrids obtained from the four cross-combinations had the expected chromosome number of 2n=36 (trihaploid) in the somatic cells. The average meiotic chromosome pairings per cell were 0.23II +35.58I + 0.141/2I (dividing univalent) for O. punctata × L. tisseranti; 0.11 II+35.51I+0.221/2I for O. punctata × L. perrieri; 0.17II+35.63I+0.11 1/2I for O. latifolia × L. tisseranti; and 0.25II+35.49I+0.151/2I for O. latifolia × L. perrieri. From these results, it seems that most of the bivalents observed at MI with a low frequency had originated from the auto-syndetic association of the chromosomes of O. punctata or O. latifolia. The results described above suggest that there is no genomic relationship between the parental species in each cross combination.
