Random amplified polymorphic DNA analysis, genome size, and genomic in situ hybridization of triploid viviparous onions

Triploid viviparous onions (Allium cepa L. var. viviparum Metzg. (ALEF.), a uct.), (2n = 3x = 24), are known in some countries only as a rare relic cro p, while in other parts of the world they are still traditionally or even c ommercially cultivated. Results indicating an identical random amplified po lymorphic DNA (RAPD) banding pattern and the same DNA content (2C = 43.4 pg ) establish the high genetic similarity and the unique origin of the Croati an clone Ljutika and the Indian clone Pran. In order to determine the paren tal Allium species of these natural triploid hybrids, genomic fluorescent i n situ hybridization (GISH) was applied. Biotinylated genomic DNAs from six diploid Allium species (A. cepa L., A. fistulosum L., A. roylei Stearn, A. vavilovii M. Pop. et Vved., A. galanthum Kar. et Kir., A. oschaninii O. Fe dtsch.) were used as probes in this study. While probes obtained from genom ic DNA of A. cepa, A. vavilovii, and A. roylei hybridized to somatic chromo somes of Ljutika probes from A. fistulosum,A. galanthum, and A. oschaninii did not. The DNA probes of A. cepa and A. roylei each completely or predomi nantly labelled one genome (eight chromosomes). A few chromosomes, the mark ers of the triploid karyotype, were not completely labelled by any probe ap plied. Our GISH results indicate that triploid viviparous onions might poss ess a complex triparental genome organization.