| Cynodon dactylon L.Pers.belongs to Cynodon L.C.Rich.,Gramineae.It distributed in tropical, subtropical and even temperate regions of eastern and western hemispheres widely, and it also distributed in Eurasia, Indonesia, Malaysia and India and other places. In China, C.dactylon mainly distributed in the south of the Yellow River, and also distributed in Xinjiang, Jilin, Qinghai, Gansu, Hebei and other places. C. dactylon own low plants, strong breeding ability, high drought resistance, forbear trampling, delicate texture, good color, it is an excellent warm-season turf grass,which is widely used as playground lawn, ornamental turf, airport lawn, soil and water conservation, slope protection berm and other areas. The cultivars were selected as control varieties in the experiment.The systematic study of the genetic diversity and excellent germplasm filtration were from the DNA molecular markers and field test. The main results were as follows:1. Sequence-related amplified polymorphism (SRAP) markers were used to detect the genetic diversity of 44 wild accessions of C.dactylon collected from Sichuan, Chongqing,Yunnan, Guizhou and Tibet in China and 8 wild accessions of C.dactylon collected from Africa.The results showed that Eighteen primer pairs produced 236 polymorphic bands, among which 206 bands were found to be polymorphic.averaged 11.4 bands per primer pair. The percentage of polymorphic bands in average was 87.29%.The Nei's genetic similarity coefficient of the tested accessions ranged from 0.569 to 0.929, and the average Nei's coefficient was0.723.The 52 accessions were classified into five major groups:â… ,â…¡,â…¢,â…£andâ…¤by cluster analysis using UPGMA. Genetic differentiation between and within five eco-geographical groups of C. dactylon was estimated by Shannon's diversity index, which showed that 63.81% genetic variance existed within group, and 36.19% genetic variance was among groups. which showed that these materials have great differences in heredity, and own significant relationship with the origin regions of accessions.2. The population's genetic structure of 63 agrestal accessions of C.dactylon collected from Sichuan, Chongqing, Guizhou, Yunnan, Tibet and Africa were analyzed using simple sequence repeat (SSR) molecular markers. The results showed that, In the six populations: (1) Eighteen primer pairs produced 353 polymorphic bands, among which 267 bands were found to be polymorphic.averaged 19.61 bands per primer pair. The percentage of polymorphic bands in average was 75.10%.The Nei's genetic similarity coefficient of the tested accessions ranged from 0.687 to 0.904, and the average Nei's coefficient was 0.788,the range was 0.217. It showed that the test materials have ample genetic diversity. (2) Analysis of cluster showed that all the accessions could be divided into 5 groups when the genetic similarity coefficient is 0.81. accessions from the same area were almost classified into the same group associated with their geographical distributions. (3) Genetic differentiation between and within seven eco-geographical groups of C. dactylon was estimated by Shannon's diversity index, which showed that 66.57% genetic variance existed within group, and33.43% genetic variance was among groups. (4) Analysis of cluster in every eco-geographical groups by Shannon's diversity index showed that they own significant relationship with the origin regions of accessions. The results provided a scientific basis for the conservation and use of the wild resources of Cynodon dactylon.3. Amplified fragment length polymorphism (AFLP) molecular markers were applied to detect the genetic variation of 59 agrestal accessions of C.dactylon collected from Africa, Sichuan, Chongqing, Yunnan, Guizhou and Tibet in China. The following results were obtained,A total of 670 bands were amplified by eleven AFLP primer pairs from C.dactylon genetic DNA, among which 663 (98.74%) bands were found to be polymorphic.The AFLP-based genetic similarity values among 59 C.dactylon accessions ranged from 0.64 to 0.96,and the average Nei's coefficient was 0.78. Genetic differentiation between and within seven eco-geographical groups of C. dactylon was estimated by Shannon's diversity index, which showed that 51.68% genetic variance existed within group, and48.32% genetic variance was among groups.Analysis of cluster and principal component analysis showed that all the accessions could be distinguished by AFLP markers and divided into 5 groups, accessions from the same area were almost classified into the same group associated with their geographical distributions.Therefore, complex geographical ecological environment is important factor to the genetic diversity and geographical distribution of C.dactylon.It will own great significance in constituting the scientific protected strategy,promoting its exploitation and utilization, and breeding new varieties.4. Sequence-related amplified polymorphism (SRAP), simple sequence repeat (SSR) and Amplified fragment length polymorphism (AFLP) molecular markers were applied to detect the genetic diversity and geographical differentiation of wild accessions of C.dactylon collected from Southwest China and Africa. The three molecular markers all showed the ample genetic diversity and geographical differentiation of the tested Germplasm. In this paper, three kinds of molecular markers'correlation were analysed. The result indicated that three molecular markers' correlation was remarkable.but the correlation coefficients were different, and the correlation between SRAP and SSR was higher.5. The adaptability of five new wild accessions of C.dactylon were evaluated comprehensively in five regions of southwest China for 3 years. The introduction variety Tifway and national variety Nanjing were selected as control varieties. The trial sites were located at Ya'an, Meishan and Chengdu in Sichuan, Rongchang in Chongqing and Dushan in Guizhou. Comprehensively analysising density, texture, homogeneity, color, mature time, resistance and so on. The test observations and Excel 2007, SPSS 12.0 software analysis showed that, Sau9926 has long green period, fast grow speed,high density,strong resistance, and it is own good turf characteristics. In the five pilot sites, the average number of the green period is 295d, the mature time is about 45d, and the density is about 200/100 cm2. Comprehensively analysising texture, color, density, resistance, mature time and green period of five new Bermudagrass lines and two control Varieties, overall performance of Sau9926 is best, which is better than two control Varieties. |
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