Investigation on Ploidy Levels of Asiatic Lily Cultivars and Analysis of the Progenies of Their Interploid Crosses
|Course||Ornamental Plants and Horticulture|
|Keywords||Asiatic lily ploidy interploid crosses aneuploid|
The Asiatic lily is one of the common lily cultivar groups, which belongs to the Liliaceae of Lilium. It also contains the most varieties of lilies. In fact, it not only has diploid cultivars (2n=2x=24), but also triploid (2n=3x=36) and tetraploid (2n=4x=48) ones. So the Asiatic lily is a good breeding material for interploid crossing.In this study,21 of the common Asiatic lily cultivars ploidy were researched on which the eight varieties (diploid, triploid or tetraploid) in the determination of pollen germination capacity, this experiment also identified the hybrids of ’4x×2x’,’3x×2x’ and ’3x×4x’ with FISH technique and traditional cytological analysis. The results were summarized as follows:1. Among the 21 Asiatic cultivars which are imported from the Netherlands,12 of them (’Eleganza’,’Monte Negro’,’Renoir’,’Black Bird’,’Butter Pixie’,’Orange Matrix’,’Petit Brigitte’,’Pink Pixie’,’Lollypop’,’Red Latin’,’Marrakech’, and ’Pollyanna’) are diploid (2n=2x=24), five of them (’Navona’,’Orange pixie’,’Elodie’, ’Vermeer’and’Lyon’) are triploid (2n=3x=36), the rest four (’Brunello’,’Tresor’, ’Val di Sole’and’Detroit’) are tetraploid (2n=4x=48).2. Eight Asiatic lily cultivars,’Renoir’,’Eleganza’,’Pollyanna’,’Brunello’,’Val Di Sole’, were investigated in the present thesis. All the cultivars, whether diploids or tetraploid, had two classes of pollen, i.e., normal stainable elliptical pollen and abnormal unstainable wrinkled pollen; As for their pollen germination, tetraploid ’Brunello’had 80% pollen germination rate, which is much higher than others ranged from 24-80%.3. By embryo rescue,18 seedling lines were obtained from 4x x 2x crosses. The analyzed 12 lines out of them are triploid (2n=3x=36).4. The fruits of both 3x×2x and 3x×4x crosses developed well. Some embryo sacs or embryos could be isolated. By embryo rescue, thirty-eight seedlings were obtained from 23 fruits of 3x×2x crosses, and 96 seedlings from 20 fruits of 3x×4x crosses. Chromosome preparation showed that the progenies of these 3x×2x/4x crosses were predominantly aneuploid, with chromosome numbers as follows:3x× 2x progenies ranged from 27 to 39; 3x×4x progenies ranged from 37 to 57. We concluded that male-sterile autotriploid lilies could be used as seed parents to cross with appropriate males.5.45 S rDNA was mapped on the chromosomes of two Asiatic cultivars and their crossing progenies using fluorescence in situ hybridization (FISH). The result showed that five pairs of chromosomes have the 45S rDNA signal in the parents and progenies of 3x×4x crosses. However, the number of the 45S rDNA sites, which chromosomes having the 45S rDNA signal, and the intensity of the 45S rDNA signal somewhat varied.