The Study Of Clonal Structure And Sex Discrimination Of Hippophae Rhamnoides L.ssp.sinensis Rousi

Hippophae rhamnoides L. ssp. sinensis Rousi, one of widely distribution subspecies of the genus Hippophae, is an economically important water and soil conservative species endemic to China. It is dioecious and has both sexual and clonal propagation. RAPD (random amplified polymorphic DNA) marker was used to detect the clonal size, clonal distribution, clonal diversity and genetic diversity within population. Meanwhile, with BSA (bulked segregant analysis), tring to find the markers linked to sex determination in the dioecious H. rhamnoides. The main results are as follows:From the result of amplification with 14 primers, the Jaccard coefficient was employed to calculate pairwise band similarities for samples using the program NTSYSpc 2.02. 26 different genotypes or clones were identified among the 184 samples analyzed, which formed 89 ramets by clonal growth. Features of size and shape of H. rhamnoides were small with only 3.4 ramets per gemets and 1.8m between neighbouring ramets on average. So, the power of clonal growth of H, rhamnoides not very high.Clonal diversity of H. rhamnoides was varied widely among eight sites. The ratio of the number of genotypes to the number of clones(G/n) was ranged from 0.15 to 0.67( mean=0.35). The proportion of geneotypes detected within population was ranged from 0.09 to 0.17(mean=0.14) and Simpson's index of diversity was ranged from 0.69 to 0.99(mean=0.85). The genotypic evenness was ranged from 0.7 to 1.0(mean=0.87).The genetic diversity of H. rhamnoides within population was lower compared to other clonal plants. The percentage of poplymorphic bands was ranged from 10% to 54.1%. Nei's gene diversity was ranged from 0.0411 to 0.1791. Shannon's index was ranged from 0.0587 to 0.2605. The means of three indexes(PPB, h, I) were 27.64%, 0.1044, 0.1536.Factors influenceing clonal structure of H. rhamnoides were explored, the results implied that the clonal structure varied according to the ratio of female to male individual within population, the age of population and habitats at some time during the history of these population.After screened 217 kinds of primes, the markers related to the gender of H. rhamnoides were not found.Based on the above results, it may obtain the below conclusions: (1) the clones of H. rhamnoides with dispersed distribution ramets as ' guerrilla' strategists; and the modle of single clone shaped the lower clonal diversity and genetic diversity within population; (2) clonal structure of H. rhamnoides was limited by many factors, such as the ratio of female to male individual within population, the age of and habitats; (3) there was balance between the two types of reproducion of H. rhamnoides in the field; (4) depended on the results, the view on what determite the gender of H. rhamnoides need further reaseach.