Chromosome Analysis Using GISH and FISH of Interspecific Hybrids.

Fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) were used for chromosome analysis of hybrids (2n=16) between onion (Allium cepa L., 2n=2X=16) and welsh onion (A. fistulosum L., 2n=2X=16). 5S rDNA, 45S rDNA, and tandemly repeated DNA (TSD) sequence were used as probes for FISH analysis. A. fistulosum specific DNA probe of telomeric repeats and A. fistulosum DNA were used for GISH analysis. In the analysis of meiotic chromosome GISH revealed that hybrids have 7 bivalants and 2 univalents chromosome and 2 univalents were derived from A. fistulosum chromosomes. In somatic chromosomes of hybrid each 8 chromosomes were derived from A. cepa and A. fistulosum, respectively. FISH signal of 45S rDNA probe in A. fistulosum was detected at secondary constriction of chromosomes, while FISH signal in A. cepa was observed in both secondary constriction and telomere of chromosomes. TDS signals in A. fistulosum chromosomes were detected at all subtelomeric of 8 chromosomes and also in 2 pericentromeric of the chromosomes, whereas TDS signals in A. cepa were observed only in subtelomeric in all chromosomes. The pattern of TDS signal in hybrid chromosomes was similar to those of A. fistulosum chromosomes. [ABSTRACT FROM AUTHOR]