| Nelumbo is well known as an ancient taxon with a very long evolutionary history.Lotus is a momentous economical crop and ornamental plant,diverse cultivars with edible,medicinal,ornamental values.Genetic diversity is play an important role in biodiversity.Knowledge of the genetic diversity and structure of population of wild lotus is not only essential for conservation of genetic resources,but also provide a richer source for lotus breeding.Some wild lotus resources are becoming endangered.Therefore,scientific evaluation and protective measures should be ommediately yake on lotus germplasm.In this paper,we are selected to investigate genetic diversity and structure of 424 wild lotus individuals from 5 countries by SSRs markers.The main results are as follows:1.A horizontal comparison of the east-west direction of lotus samples from Russia and China:Among the 13 SSR markers that selected from 30 SSR markers,with averages of PIC were 0.502.It indicated that the genetic diversity of wild lotus populations at these ssr loci was at a high level.A total of 68 bands were selected 13 SSR markers from 208 lotus samples.The number of alleles per locus ranged from 3(Nelumbo-06)to 9(Nelumbo-32),with a average of 5.23.Wild lotus had a high genetic diversity at species level,a low genetic diversity was revealed at population level.The special reproduction pattern or the horizontal geographic segregation of the populations may be the reason for the high genetic diversity at the species level.The lower population level may be caused by the longevity and vitality of lotus seeds,the inherent characteristics of ancestral species,and the activities of waterfowl and human beings.A study on the genetic structure of the lotus shows that the genetic relationship between the two wild lotus populations in the Caspian Sea of Russia and other populations is very far away.The reason is that in the early stage,different migration routes and evolution mode formed different clustering.The Russian population in Northeast China and its vicinity may have originated from the Songhua River basin.Because of the flood stream,lotus migration to the Wusuli River and became a independent population.In order to protect the populations of the Caspian Sea and Songhua River basin in Russia,it is suggested to establish a nature reserve for local protection.2.Study on genetic Diversity and population structure of Wild Lotus in tropical region:There are 9 SSR markers with averages of PIC were 0.593.The higher polymorphism can effectively detect the genetic diversity among populations and within populations.A total of 64 bands were selected 9 SSR markers from 216 lotus samples,with a average of 7.11.It was found that the wild lotus germplasm resources in tropical area had the same moderate genetic diversity as cultivated species.With the improvement of ornamental value of lotus plants,people are demanding more and more attention.The emergence of more and more hybrid varieties enriches the genetic diversity of cultivated species.Based on the results of principal component analysis,cluster analysis and structure analysis,it is suggested that Thailand may be one of the postglacial shelters,especially the t5 population in Thailand.With the pleasant climate conditions,ocean current movement and other factors,wild lotus moved to India and Australia,long time adaptation has formed the present situation.It is recommended that all communities in Thailand be protected in situ.In India and Australia,the local protection strategy is generally adopted to adopt a few residential groups with different homologous gene banks to adopt the ex situ conservation policy.Two kinds of protection strategies at the same time,in order to protect the heritage of wild lotus plants diversity.At the same time,we can try some new conservation strategies,such as the establishment of seed bank of lotus plants. |
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