DETECTION OF ALIEN ORYZA-PUNCTATA KOTSCHY CHROMOSOMES IN RICE, ORYZA-SATIVA L., BY GENOMIC IN-SITU HYBRIDIZATION

Genomic in situ hybridization (GISH) using total Oryza punctata Kotsch y genomic DNA as a probe was applied to detect alien chromosomes trans ferred from O. punctata (W1514: 2n=2x=24: BE) to O. saliva Japonica cu ltivar, Nipponbare (2n=2x=24: AA). Only 12 chromosomes in the interspe cific hybrids (2n=3x=36: AAB) between autotetraploid of O. saliva cult ivar Nipponbare and a diploid strain of O. punctata (W1514) showed int ense staining by FITC in mitotic metaphase spreads. Only one homologou s pair of chromosomes out of the 12 pairs of O. saliva chromosomes, wh ich is probably chromosome 8, contained similar repetitive sequences a s present in O. punctata and were frequently slightly stained by GISH. Monosomic alien addition line(MAAL)s 7 (2n=2x+1=25: AA+7B: Type II) a nd 10 (2n=2x+1=25: AA+10B) were characterized by an additional single chromosome which had been intensely stained by GISH. Thus, GISH using O. punctata total genomic DNA allowed the detection of a specific chro mosome transferred into cultivated rice. This method can be useful to search introgressed chromosomal segments or translocated chromosomes i n the progenies of the MAALs each carrying an alien chromosome of O. p unctata in rice.