LAUSR

Abstract Sixteen Narcissus cultivars were analyzed for their loci of 45S rDNA and 5S rDNA on mitotic metaphase chromosomes using fluorescence in situ hybridization (FISH), their male fertility by testing their pollen germination and female fertility based on their crossability. The results and analysis showed that thirteen cultivars, including ‘Queen's Day’, ‘Pink Charm’, ‘Stadium’, ‘Mount Hood’, ‘Eline’, ‘Accent’, ‘Dutch Master’, ‘Flower Parade’, ‘Replete’, ‘Las Vegas’, ‘Flower Surprise’, ‘Ice Follies’ and ‘Easter Born’, were autotetrapliod (2n = 4x = 28 = EEEE) and they were obtained from chromosome doubling, because they had similar FISH karyotypes and their male and female fertility match with autotetraploid; For similar reasons, Chinese Narcissus ‘Jinzhanyintai’ was autotriploid (2n = 3x = 30 = AAA) caused by unilateral sexual polyploidization, ‘Pink Parasol’ was identified as allotetraploid (2n = 4x = 30 = CCDD), and ‘Bridal Crown’ had one A genome and one B genome, meaning it was selected from interspecific hybridization (2n = 2x = 17 = A + B). It was concluded that FISH with rDNA probes was powerful tool to analyze Narcissus genomes. The results would be valuable to guide breeding in Narcissus.