Investigation The Germplasm Resources On Wild Group Of Ruditapes Philippinarum In Liaoning Coastal

Ruditapes philippinarum is an economically important marine shellfish. Liaoning Provinceis the main producing areas of shellfish, and Ruditapes philippinarum farming is an importantpart of it. Liaoning province, including the Yellow Sea and Bohai Sea, has a special geographicallocation, resulting in a different environmental habitat of Ruditapes philippinarum, anddifferences on their morphology and genetics. In recent years, due to the seeds of Ruditapesphilippinarum transfer from southern areas to northern part of china, the changes inenvironmental conditions and over-harvesting, the wild populations of Ruditapes philippinarumin Liaoning were severely affected. The study on morphology and molecular biology of wildpopulations of Ruditapes philippinarum were conducted to protect the existing wildlife resourcesand establish effective measures to maintain the wild populations of Ruditapes philippinarum inLiaoning. Meanwhile, this work provide a basis for selective breeding of high yielding anddisease resistance varieties, breakthrough the bottleneck and sustainable development of theclam aquaculture industry in Liaoning. In this study, the morphological characteristics andgenetic diversity were analyzed by morphological measurement and molecular markers from thecoastal wild populations of Ruditapes philippinarum in Liaoning. The main findings are asfollows:1. Morphological variations analysis of different geographical populations of wild populations ofRuditapes philippinarum.Based on nine morphological characters of populations of Ruditapes philippinarum fromChangxing Island, Lvshun, Yingkou, Panjin, Jinzhou, Sea Island, Heishijiao and Jinzhou formorphological analysis. Multivariate morphometrics was used to investigate their morphologicalvariations among the eight different geographical populations. The results showed that: most ofthe Changxing Island groups are flat shell, shell thick and heavy; Lvshun group largestpopulation growth in shell length bias degree; Yingkou fattest population shell meat, shells andlightest; Jinzhou groups shell "convex" type most obvious; ocean shell Island populationheaviest; Heishijiao groups thinnest shells; Golden State groups shell "convex" the most obvioustype, quality, largest, heaviest shells. These characteristics reveal obvious morphologicaldifferences between different groups. Conducted on nine standard form means clusteringanalysis showed: Lvshun, Jinzhou, Panjin and Heishijiao groups converge to a branch;Changxing Island, Sea Island and the Jinzhou as an aggregation group, while the performance ofindependent groups Yingkou groups. The results show that the variation in morphology andgeographic distance eight groups, and no significant association.2. Genetic diversity of Ruditapes philippinarum populations from Liaoning provience revealedby SSR markers.In order to provide guidelines for conservation strategies and management programs,genetic diversity of eight wild populations of the clam Ruditapes philippinarum from coast ofLiaoning was analyzed using twelve microsatellite markers, and the degrees of geneticdifferentiation between them were compared. In this study, a set of7genomic simple sequencerepeat (SSR), and5expressed sequences tag (EST)-derived SSR markers were analyzed on eight wild R. philippinarum populations to assess the genetic diversity and population differentiation.A total of114alleles were detected on12SSR loci, and the number of alleles per locus in eachpopulation ranged from2to11, and allelic richness per locus varied from2.00to10.88for eachsample. The average of observed and expected heterozygosity ranged from0.386to0.550, andfrom0.533to0.707, respectively. Pairwise FST values indicated that all population pairs hadsignificant genetic differentiation (overall FST=0.242, P <0.05). Cluster analysis usingUPGMA separated the eight populations into two groups. This study will shed light on thedomestication and cultivation on population genetic diversity of R. philippinarum, and alsoprovide the foundation for conservation of R. philippinarum germplasm resources in clambreeding practice.