The Clone Structure And Clone Reproductive Fitness Of Hybrids And Their Parents Of Natural Hybrid Zone In Hippophae Goniocarpa Ssp.goniocarpa

Natural hybridization is an important evolutionary mechanism of angiosperms, which is the hot topic in the plant evolutionary biology today. The research about the clone fitness of hybrids and their parents of the hybrid zone is significant to reveal the maintenance mechanism and the evolutionary dynamics of the hybrid zone. Hippophae, the pioneer species of community succession, has important ecological and economic value. The characteristics of clone reproduction is an important aspect of plant fitness, the clone fitness of hybrids (H. goniocarpa ssp.goniocarpa) and parents(H. rhamnoides ssp. sinensis and H. neurocarpa ssp.neurocarpa) maybe has an important influence onthe evolution of the hybrid zone. In the present thesis, the experiment studies on the clone structure and clone reproductive fitness of hybrids and their parents on the hybrid zone of Gongbeiwan, Babaohetan and Xiaodongcaogou in Qilian County of Qinghai Province, were compared using SSR marker in order to provide evidence to the maintenance mechanism of hybrid zone in Hippophae. The main results and conclusions are as follows:(1) The genetic diversity of H. goniocarpa ssp. goniocarpa and their parentsThe genetic diversity is different of H. goniocarpa ssp. goniocarpa of3hybrid zones. The Nei’s gene diversity and Shannon’s index of H. rhamnoides ssp. sinensis were ranged from0.0487~0.3220and0.0987~0.4769the Nei’s gene diversity and Shannon’s index of H. neurocarpa ssp. neurocarpa were ranged from0.1178~0.2252and0.1982~0.3585the Nei’s gene diversity and Shannon’s index of H. goniocarpa ssp. goniocarpa were0.0805~0.2951and0.1418~0.4455. Overall, the genetic diversity of3groups is not lower than other clone plants. The genetic diversity is different of H. goniocarpa ssp. goniocarpa of3hybrid zones, higher or lower than their parents, or between in their parents.(2) The clone structure of H. goniocarpa ssp. goniocarpa and their parentsThe number of clones and the distance between ramets of H. goniocarpa ssp. goniocarpa and their parents is different. Population of H. rhamnoides ssp. sinensis, the number of clones is1.0~8.5, the distance between ramets on average is3.3~13.4m Population of H. neurocarpa ssp. neurocarpa, the number of clones is1.6~1.8, the distance between ramets on average is3.5~7.0m Population of H. goniocarpa ssp. goniocarpa, the number of clones is1.5~3.5, the distance between ramets on average is1.4~7.0m. The results showed higher clone reproduction of hybrids than their parents of3hybrid zones.The clone diversity of H. goniocarpa ssp. goniocarpa and their parents is different. Population of H. rhamnoides ssp. sinensis, The ratio of the number of genotypes to the number of clones(G/n) is0.12~1.00, Simpson’s index of diversity(D) is0.495~1.000Population of H. neurocarpa ssp. neurocarpa, The ratio of the number of genotypes to the number of clones(G/n) is0.35~0.63, Simpson’s index of diversity(D) is0.919~0.988Population of H. goniocarpa ssp. goniocarpa, The ratio of the number of genotypes to the number of clones(G/n) is0.29~0.67, Simpson’s index of diversity(D) is0.835~0.995. The results showed higher clone reproduction of hybrids than their parents of3hybrid zones. Overall, the clone diversity is not lower than other clonal plants. The clone diversity of H. goniocarpa ssp. goniocarpa is lower than their parents. Therefore, the clone reproductive capacity of H. goniocarpa ssp. goniocarpa is higher than their parents.(3)Clone fitness of H. goniocarpa ssp. goniocarpa and their parents of hybrid zone and its influencing factorsComparison of clone fitness was made between hybrids and their parents of3different hybrid zones. The results showed the clones fitness in populations of H. goniocarpa ssp. goniocarpa is higher than their parents, the clone reproductive capacity is strong. The community characteristics were compared between the population of H. goniocarpa ssp. goniocarpa and their parents of3hybrid zone. The result showed the community characteristics had a certain influence on clone fitness of hybrids and their parents. The clone reproductive capacity is stronger much more when the index of community characteristics is lower.(4)The maintenance mechanism of hybrid zone of H. goniocarpa ssp. goniocarpaThe hybrid H. goniocarpa ssp. goniocarpa of can maintain and expand the size of population by clone reproduction. And the clone population is polyclonal, can increase the genetic diversity. Then contribute to maintain the balance and development of the hybrid zone.