Study On The Hybridization Between Different Ploidy Levels Of Asiatic Lily And Lilium Tsingtauense

The ploidy level, pollen morphology and pollen germination of twelve Asiatic lilies (’Black Bird’,’Butter Pixie’,’Orange Pixie’,’Orange Matrix’,’Petit Brigitte’’Pink Pixie’,’Elodie’,’Lyon’,’Brunello’,’Detroit’,’Pollyanna’and A31) and Lilium tsingtauense, were investigated in the present paper. Hybridization between different times Asiatic lily and Lilium tsingtatense was conducted with cut style pollination and embryo rescue,14progenies were obtained. All the Asiatic lilies, Lilium tsingtauense and4progenies of’Petit Brigitte’×Lilium tsingtauense were analyzed using FISH with45S rDNA as probe. The results showes,1. All the cultivars have two classes of pollen, i.e., normal stainable elliptical pollen and abnormal unstainable wrinkled pollen. The ratio of normal stainable elliptical pollen in tetraploid Asiatic cultivars is higher than that in diploid ones. While the ratio of abnonnal unstainable wrinkled pollen in diploid Asiatic cultivars is higher than that in tetraploid ones.2. The tetraploid’Brunello’and’Detroit’had80%pollen germination rate, which is much higher than other diploids ranged from4%-41%. And the Lilium tsingtauense had55%pollen germination rate.3. They have different ploidy levels. Seven Asiatic cultivars (’Butter Pixie’,’Orange Matrix’,’Petit Brigitte’,’Pink Pixie’,’Pollyanna’) are diploid (2n=2x=24). Two cultivars (’Elodie’,’Lyon’) are triploid (2n=3x=36). The other three cultivars (’Brunello’,’Detroit’, A31) are tetraploid (2n=4x=48). And the Lilium tsingtauense is diploid (2n=2x=24).4. The FISH analysis of seven Asiatic cultivars showed, chromosomes1,4and7have invariable sites of45S rDNA in all the diploid Asiatic cultivars, and same phenomenon observed in tetraploid Asiatic cultivars. Most Asiatic cultivars have the same sites of45S rDNA on chromosomes2except that no signal was on one homolog of "Pink Pixie’and different sites of45S rDNA on the pair of chromosomes2of ’Orange matrix’. However,45S rDNA distribute variably on chromosomes5,6and9among these diploid and tetraploid Asiatic cultivars. In most cases, only one homolog of each set of chromosome5,6and9has45S rDNA. Even in the tetraploid cultivars ’Brunello’and’Detroit’, only one homolog of chromosome5,6and9have45S rDNA, suggesting that the two tetraploid must not have result from chromosome doubling.5.’Petit Brigitte’, Lilium tsingtauense and the progenies are all diploid (2n=2x=24).’Petit Brigitte’has10loci of45S rDNA distributed on chromosome1,2,5and7; Lilium tsingtauense has8on3,4,5and10respectively. All four progenies have9loci of45S rDNA, unambiguously, coming from’Petit Brigitte’and Lilium tsingtauense.To sum up, hybridization between different species can be conducted with cut style pollination and embryo rescue, even though there are some difficult. And also there are difficult in hybridization between different polity levels. It seems that45S rDNA could be not only as chromosome marker to identify interspecific hybrids but also used for analyzing the speciation in Lilium.