Visualization of Oryza eichingeri chromosomes in intergenomic hybrid plants from O. sativa × O. eichingeri via fluorescent in situ hybridization
Digoxigenin-labeled total genomic DNA from Oryza eichingeri was hybridized in situ to somatic chromosome preparations of F1, F2, backcross progenies, and a pollen-derived tetraploid plant (E24) from O. sativa (2n = 24, genome AA) × O. eichingeri (2n = 24, genome CC), which allowed a definitive discrimination between A- and C-genome chromosomes. Twelve chromosomes in F1, F2, BC1, and twenty-four chromosomes in plant E24 were clearly revealed to be of O. eichingeri origin, thus confirming that both BC1 and F2 were allotriploids (2n = 36, AAC) while plant E24 was an amphiploid (2n = 48, AACC). In addition, the presence of O. eichingeri chromosomes in four alien addition lines was characterized. The results suggest that FISH/GISH may be a powerful tool for monitoring the O. sativa-alien chromosome in the progenies of rice interspecific hybridization.Key words: fluorescent in situ hybridization, Oryza sativa, Oryza eichingeri, amphiploid, alien addition lines.