| Sweetpotato(Ipomoea batatas(L.)Lam.)plays an important role in agricultural production,it's also one of the dominant crops for characteristic industries development and targeted poverty alleviation in China because of its characteristics of high yield,strong adaptability and balanced nutrition.Since the implementation of the varieties' registration rules for sweetpotato and other crops in May 2017,the number of the registered varieties was increasing rapidly.The problems of high similarity among varieties and varieties naming disorder in seedling market brought challenges to the registration management of varieties.Meanwhile,sweetpotato breeding bottleneck attributed to a narrow genetic basis for a long time which hindered the breeding process.This study was to assess the genetic diversity and prove pedigree of the registered sweetpotato varieties in China using phenotypic markers and SSR markers.Preliminary DNA fingerprint was constructed based on SSR markers.The results were as follows:1.Principal component and cluster analysis were performed on 115 registered sweetpotato varieties using 15 phenotypic traits.Five principal components were obtained,the cumulative variance contribution rate was 65.17%which generally reflected the comprehensive information of the traits investigated and revealed the correlation between some traits..The UPGMA cluster divided the accessions into three groups.The clustering results were different from the pedigree relationship and the place of origin.2.Genetic diversity assessment and DNA fingerprint construction were performed based on TP-M13-SSR technology.The PIC values of 28 pairs of SSR primers collected and screened were between 0.45 and 0.84.A total of 163 polymorphic bands were amplified in 115 accessions.Nei's genetic distance and AMOVA showed the narrow genetic background of the registered sweetpotato varieties.Both neighboring-join tree and population structure divided 115 accessions into three clusters.The clustering results were similar with the pedigree relationship.Accessions from the same region were scattered in the neighboring-join tree.The 34 accessions had a high degree of mixed ancestry and genetic background was complex while taking the Q value of 0.6 as a reference.Preliminary core germplasms database with29 accessions were constructed,which reduced genetic redundancy effectively.Preliminary fingerprints of 115 accessions were constructed with seven pairs of core primers reported by the other researchers.Genetic diversity assessment,core germplasms development and fingerprints construction of registered sweetpotato varieties were revealed by morphological and SSR markers,which could help make better conservation decisions,guide breeding and provide management services for the registered sweetpotato varieties. |
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