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Study On Germplasm Resourses And Genetic Diversity Of Lilium Native To Northeast China

Posted on:2011-01-25Degree:DoctorType:Dissertation
Country:ChinaCandidate:L P RongFull Text:PDF
GTID:1103330332485753Subject:Ornamental horticulture
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Lilium, a perennial bulbous flower belonging to the Liliaceae, is one of the five most important cut flowers.With its big and colorful flower, beautiful stature and fragrance, it is cultured extensively worldwide and paly an important role in the floral market. In China, there are abundant wild resources of Lilium with a total of 55 species, in which 36 species and 15 varieties are native species. But many of them have yet not been used, and a great number of precious resources are endangering because of natural disasters. Therefore, in this paper, 119 wild Lilium resources native to Northeast China were investigated and collected, and the genetic relationship and diversity were studied at morphological, palynological, cytological and molecular level, which lay a foundation for the collection, preservation, conservation, classification, evaluation and utilization of wild Lilium species. The results were as follows.119 accessions resources of wild Lilium germplasm were collected native to Northeast China. The germplasm accessions collected.were classified into 6 species and 3 varieties, including 25 Lilium lancifolium Thunb.,15 L. pumilum DC.,12 L. dauricum Ker-Gawl,2 L. cernuum Komar.,7 L. amabile Palib.,7 L. distichum Nakai,40 L. concolor Salisb. var. buschianum (Lodd.) Baker,3 L. concolor Salisb. var. megalanthum Wang et Tang,8 L. leichtlinii Hook.f. var. maximowiczii (Regel) Baker. But L. callosum Sieb. has not been collected until now. Based on the geographical distribution, L. concolor var. buschianum was believed to be the most widely distributed species, and it was collected from 16 cities in the northeastern region. L. lancifolium was one of the most widespread species with high adaptability in China, and was collected from diverse habitats such as bushes, road side, hillside, or grassland. Only 2 accessions of L. cernuum were collected from Fengcheng city and Fushun city, and only 3 accessions of L. concolor var. megalanthum were collected from Tieling and Jiaohe city. Therefore, the distribution of L. cernuum and L. concolor var. megalanthum was rather narrow as compared to other species. L. amabile also had narrow geographic distribution, which seemed to be concentrated in Dandong city near North Korea. The analytic hierarchy process was employed to evaluate ornamental characteristic and utilization potential of 9 collected species. It seemed that L. lancifolium and L. cernuum got the highest score Therefore, L. lancifolium and L. cernuum had an excellent exploitation potential. Among the 9 Lilium species, only L. cernuum had obvious purple flowers. Also, its population was very small. Besides, L. pumilum, L. concolor var. buschianum and L. leichtlini var. maximowiczii. got higher scores. Therefore, great importance had been continuously attached to L. lancifolium, L. cernuum, L. pumilum, L. concolor var. buschianum and L. leichtlini var. Maximowiczii. L. dauricum, L. distichum and L. concolor var. megalanthum got the lower score. However, that does not mean that they are worthless. They have a relatively high value in some certain aspects that implying that we should also pay attention to these species.16 morphological characteristics from 50 populations of 6 species and 3 varieties germplasm resources were researched. The results showed that the morphological characteristics were significantly different with high diversity among the wild lilies native to northeast China. The coefficient of variation were high and more than 25% except for leaf long (23.35%), of which the cofficient of variation of style length and leaf width were most highest, up to 64.57% and 59.37% respectively. The morphological diversity was high, and the average diversity index was 1.85, of which the diversity index of leaf length and inner petal width, were highest, up to 2.88 and 2.87 respectively. In PCA analysis, the first four principal components represented 87.51% of the morphological diversity. The significant morphological divergence consisted of outer petal width, inner petal length, inner petal width, flower color, flower type, peduncle length and leaf length.Based on the morphological data, 50 wild lilies were cluster into three groups. The first group included 30 accessions with the smaller flower, L. pumilum, L. concolor var. buschianum, L. concolor var. megalanthum, L. amabile and L. cernuum, the second group included 19 accessions with large flower, L. lancifolium, L. leichtlinii var. maximowiczii and L. dauricum, and the third group included L. distichum.The pollen was observed by light microscope and scaning electronic microscope. The result showed that pollen exists for single grain, and the symmetry is strong. The pollen shapes of wild Lilium are boat shape in equator view and there is a ditch which extends several to the two-pole. The pollen shapes of Lilium are oval in polar view and the edge has hollow, for sprouts the ditch. There was very significant difference on polar axis, equarorial axis, P/E among Lilium species. The result from multiple comparions showed that there was very significant difference among some Lilium species, and no significant difference among other Lilium species. Also, there was no significant difference in L. amabile from different areas. and There was very significant difference in L. lancifolium and L. pumilum from different areas.The ultrastructure of pollen surface basic type observes is the network, the net keel belt-shaped, granulated, plate bead shape or is irregular, forming the polygon or the irregular mesh. The mesh size, the density of distribution and the shape characteristic have the certain difference in different species, mesh size of some species is bigger, and others is smaller. The mesh in near polar middle is obviously bigger than the ditch edge by scaning electronic microscopeThe roots were used to study the effects of the sampling time, the pretreatment chemicals, hydrolysing time and staining on the chromosome squashing. The results showed that the optimal sampling time of roots was about 8:30~9:30 am. Of the three pretreatment chemicals used,0.1% colchicine solution for 24 hours was proved to be best. Then the root-tips were fixed with Carnoy solution for 6 hours and hydrolysed with 1 mol·L-1 HCl for 5 min (8min for L. lancifolium) at 60℃and stained with modified Carbol fuchsin solution. A very good effect of chromosome squashing could be obtained with this method. The chromosome of 9 Lilium species collected was bigger, and showed the same basic chromosome number x=12 and similar karyotype features, two large metacentric chromosome pairs and ten subtelocentric or telocentric pair. L. lancifolium was triploid (2n=3x=36) and the other species were diploid (2n=2x=24). Interspecific differences was mainly the number of chromosomes of different types and their ranking position in the karyotype, followed by the difference of the number and position of the satellite. The karyotype of all the species was 3A except for L. dauricum Ker-Gaw. with 3B. The variations of chromosome number were observed in the root-tip cells of 8 species except for L. distichum, but the variation frequency was relatively low. The aneuploidy cells of 2n=2x=22,25,26 were observed in seven diploid species with the rate of 2~10%. The aneuploidy cells of 2n=3x=34,37 were observed with the rate of 9%, and the cells with haploid chromosome number(2n=x=12) had also been observed in the triploid species L. lancifolium. B-chromosome was also observed in L. dauricum; L. concolor var. buschianum, L. concolor var. megalanthum, L. pumilum and L. lancifolium. There was 1 B-chromosome in L. lancifolium, L. concolor var. buschianum and L. concolor var. megalanthum,2 B-chromosomes in L. dauricum, and 1 B and 2 B-chromosomes in L. pumilum. Especially, the occurrence frequency of B-chromosome in L. pumilum was highest, up to 10%The DNA polymorphism from 50 accessions of 6 species and 3 varieties in Lilium native to Northeast China was studied using randomly amplified polymorphic DNA (RAPD) markers in the experiment. A total of 105 clear and reproducible bands were generated from twelve RAPD primers, of which 86 were polymorphic, with an average of 7.2 polymorphic bands, which indicated that the 50 wild lily accessions had high level of genetic diversity. The dendrogram based on RAPD data were constructed by using UPGMA analysis. The 50 wild lilies clustered into two groups. The first group included 38 accessions involved in L. leichtlinii var. maximowiczii, L. lancifolium, L. dauricum, L. amabile, L. distichum, L. concolor var. buschianum and L. concolor var. megalanthum. The second group included 12 accessions involved in L. pumilum and L. cernuum. The first group can be divided into two subgroups. The first subgroup involved in L. leichtlinii var. maximowiczii, L. dauricum, L. amabile, and L. distichum, and the second subgroup involved in L. lancifolium, L. concolor var. buschianum and L. concolor var. megalanthum. The results showed that L. lancifolium had close genetic relationship with L. concolor var. buschianum, but distant genetic relationship with L. amabile, L. pumilum and L. cernuum of Sect Sinomartagon. The genetic relationship was close between L. pumilum and L. cernuum.
Keywords/Search Tags:Lilium, Genetic diversity, Morphological characteristics, Karyotype, Pollen, B-chromosome, RAPD
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