FISH and GISH reveal genome composition of popular Narcissus cultivars and the possible ways of their origin

Abstract

There are thousands of Narcissus cultivars, however; their genome compositions are not so clear, except that their ploidy levels are extensively investigated. The present study analyzed eight popular cultivars using GISH or/and FISH. The present results clearly revealed their genome composition: 'Bridal Crown' was diploid (2n = 2x = 17 = 10 + 7 = AE) rather than aneuploid, 'Jinzhanyintai' was autotriploid (2n = 3x = 30 = 10 + 10 + 10 = AAA) rather than allotetraploid or hexaploid, 'Tête-à-Tête' was allotriploid (2n = 3x = 24 + B =10 + 7 + 7 + B = AEE), 'Cultivar X' was also allotriploid (2n = 3x = 24 = 10 + 7 + 7 = AEX), and 'Dutch Master', 'Replete' and 'Queen's Day' were all autotetraploid (2n = 4x = 28 = 7 + 7 + 7 + 7 = EEEE). Together with others reports, we concluded that 'Tête-à-Tête' was composed of one genome of N. tazetta, one genome of N. cyclamineus, and one genome of N. pseudonarcissus, and that 'Pink Parasol' was aneuautotetraploid (2n = 4x + 2 = 30 = 7 + 7 + 7 + 7 + 2 = EEEE + 2 ) rather allotetraploid (2n = 4x = 10 + 10 + 5 + 5 = CCDD). Based on the cultivars' genome composition and origin, it is concluded that distant hybridization, sexual polyploidization and chromosome doubling play different roles in breeding modern Narcissus cultivars.