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Genetic Diversity Analysis of Watercress Germplasm Resources Based on Phenotypic Traits and SNP Markers |
JI Qun ☆,LI Shuangmei ☆,ZHU Honglian*,KE Weidong* |
Institute of Vegetables,Wuhan Academy of Agricultural Sciences,Wuhan 430207,Hubei,China |
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Abstract This paper investigated and analyzed 8 agronomic traits of 19 watercress accessions originated from different regions at home and abroad,conserved in Wuhan National Germplasm Repository for Aquatic Vegetables.The paper also carried out reduced-representation sequencing on watercress germplasm resources by specific length amplified fragment sequencing( SLAF-seq technology) and studied the genetic diversity.The results showed that the variation of all the qualitative traits(leaf colour,stem colour,top leaflet shape)was not obvious.The variable coefficient of quantitative characters(top leaflet length,top leaflet width,plant height,stem diameter,stipe length) were lower(7.69%-16.45%),indicating a narrow scope for quantitative characters variation.But,there were individuals with fine properties still existing,such as ‘yangguang-2 watercress’,‘damiaochangyesheng watercress’ and ‘yulongxueshan watercress’.They could be selected for breeding.A total of 49.21 Mb read data,355 141 high quality SLAF tags and 33 386 polymorphism SLAF tags were obtained by using SLAF-seq technology.Moreover,102 704 high quality SNP sites were developed and obtained from 33 386 polymorphic SLAF tags.Clustering analysis based on 8 phenotypic traits divided the 19 accessions of watercress germplasm resources into 2 categories,similar to the results gained based on SNP clustering analysis.Population structure analysis and PCA analysis all divided these 19 accessions of watercress germplasm resources into one group,indicating that although there existed variation in phenotype,the genetic background was narrow and genetic diversity level was low.The genetic diversity exponential π value of landrace and wild watercress was 0.012 1 and 0.012 2,respectively,the diversity differentiation index between landrace and wild watercress was low(Fst = 0.030 2),indicating that landrace and wild watercress was all belonged to one group.The results showed that the suspected wild watercress widely distributed in the fields of China might not be wild resources,but formed by escapes from cultivated varieties,and all resources were likely to originate from the same cultivated type.
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Received: 09 April 2020
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