| Salix psammophila is a desert shrub distributed mainly in Mu Us Desert and Kubu Qi Desert of Ordos in northwestern China.S.psammophila exhibits extraordinary adaptation to drought,high temperature,wind erosion,sand burying and strong abiotic stress.It is an excellent tree species for local windbreak,sand fixation and vegetation restoration.It is also a new raw material for biofuel,wood profiles and the preparation of activated carbon,which has important production and application value.In this study,nine quantitative and seven quality phenotypic traits of 646 genets from 17 populations were utilized for statistics to analysis the morphological diversity and variation between populations.Moreover,528 genets from 17 populations were selected for genetic diversity and population genetic structure analysis by SSR molecular marker,and the genetic differences between phenotype and molecular genetic structure were discussed.We try to find the relevant SSR marker between molecular markers and phenotypic traits to provide valuable information for the improvement of related traits and the location of functional genes.We construct the fingerprint map and core collection of S.psammophila,which provide theoretical basis for the identification of genets.It is beneficial to preserve,evaluate and manage the germplasm resources of S.psammophila.The results were as followed:(1)There were abundant phenotypic variation among and within populations for quantitative traits of S.psammophila germplasm resources,and the coefficient of variation ranged from13.93%to 33.03%.The phenotype and molecular markers showed that the main source of variation was within populations,and the breeding of different genets in the population was the main research direction of directional breeding.(2)Phenotypic and SSR molecular marker principal components and cluster analysis showed that there was a significant difference between P17,P1,P2 and central distribution populations.The populations in the distribution area may show a trend of expansion from the center to the marginal populations.At the same time,both the phenotypic and genetic distance were corrected with geographical distance.So marginal population have a tendency to form geographical variation.(3)The characteristic band were selected to construct fingerprinting.The most genets were identified when using I primer,and the germplasm identification rate(P2)reached 51.72%;random primer combination method was used to determine the optimal mapping.I+J+U was the best combination of primers that primer combination germplasm identification rate(PCa)reached 90.42%.(4)Phenotypic traits and molecular marker SSR were used to correlation analysis.GLM model analysis showed that 19 primers was significant correlation(P<0.05)with nine phenotypic traits and a total of 57 primer combinations,phenotypic variation explained rate ranged from 9.2%to 67.45%;MLM model analysis showed that 14 primers was significant correlation(P<0.05)with nine phenotypic traits and a total of 19 primer combinations,phenotypic variation explained rate ranged from 4.14%to 66.91%.(5)The improved least distance stepwise sampling method and least distance stepwise sampling based on population method was used to construct S.psammophila core collection using SSR molecular marker.L3 core collection consists of 53 genets.The L3 core collection variance percentage difference(VD%)was 14.29%,the changeable rate of coefficient of variance(VR%)was 100.47%and coincidence rate of range(CR%)was 66.39%.So L3 core collection was suitable for core collection of S.psammophila,because it had good representation,heterogeneity and diversity. |
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