| Lilium is a great genus which includes abundance species and cultivars. Lilium is also one of the important ornamentals crops and ranks seventh among the cut flowers auctioned in the world. Because of the glorious blooms and scent, they were mass-produced as potted plant, cut flower and courtyard plant.China is the distribution centre of lilium .There are almost 46 out of 96 species in China. While for some reasons, the breeding of lily is undeveloped. At present, there are not famous varieties and strains.which are breeded in china. The bulbs which have been cultured for trade chiefly depend on import.The Asiatic Oriental and Longiflorum hybrids of Lilium are the world-wide hybrid strains , which are largely traded in the international market. In the present study, diversity of RAPD markers, pollen character and micropropagation of lily cultivars were studied. By combination of results in the present study with others that have been conducted in other previous research and analysis of diversity, breeding background of the above three strains , relationships among the cultivars, some conclusion expected to be drawed for the breeding of ornamentals lily in China.Based on 15 random primers , RAPD polymorphism of 15 lilium cultivars were detected. Of 218 bands, 216 were polymorphic (99.08%) . The PPB, h and /of the Asiatic cultivars were 40.83%, 0.1654, 0.2415, respectively; the PPB, h and I of the Oriental cultivars were 42.20%, 0.1600, 0.2381, respectively; the PPB, h and /of the Longiflorum cultivars were 25.23%, 0.1072, 0.1551 respectively. The lily cultivars of the Asiatic hybrids had the highest genetic diversity; Longiflorum hybrids had the lowest genetic diversity.Neis genetic distance among the cultivars showed that value of gernetic distance among the cultivars from the same strain were lower than that from different strains. The results revealed that cultivars from the same strain had much closer relationships; the cultivars from different strains had less close relationships. Among these three strains, gernetic distance between Asiatic cultivars and Oriental cultivars was the lowest, which was the highest between the Asiatic cultivars and Longiflorum cultivars. The Oriental strain and Asiatic strain had relatively closer relationship.The pollen grains of some cultivars from the three hybrid strains were examined underscanning electron microscope (SEM). The pollen character and gross morphology in Lilium were discussed: The pollen grains were generally elliptic and monocolpate(distal). Evidence from pollen morphology indicated that the pollen size, P/E value and exine sculpturing among species, cultivars were different in varying degrees, which could be used to distinguish cultivars. The main character of cultivars from the same strain are similar, which revealed that these cultivars had closer relationships. The exine sculpturing also revealed that there was more similarity between Asiatic Hybrids and Oriental Hybrids.In present study, The difference in clonal propagation of the three strains cultivars were discussed through culture of scales. The induction proportion and the growth status of the buds and little bulbs, the proliferation of the buds and their growth status had direct correlation on genotype of lily. Cultivars from the same hybrid strain had more similarity .The study showed the flower colour and shape were related with genetic diversity and relationships of lily cultivars. The Oriental and Asiatic hybrid cultivars were rich in flower colour and shape, they also had high genetic diversity. The Longiflorum hybrid cultivars was poor in flower colour and shape, they also had lower genetic diversity. In the same strain, cultivars that were same in flower colour were more familiar than others. The above results could be used to distinguish the relationship of lily cultivars from the same strains.The main results are as follows:1. The lily cultivars of the Asiatic hybrids strains had the highest genetic diversity; Longiflorum hybrid strains had the lowest gene...
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