| Polygonum cuspidatum,as a traditional Chinese medicine,has the effects of dispelling wind-evil,damp elimination,analgesic therapy,relieving coughs,and reducing sputum.As a raw material medicine,it can extract resveratrol,polydatin,emodin,and other components.In recent years,the wild resources of Polygonum cuspidatum have gradually dried up,and the cultivated Polygonum cuspidatum germplasm is mixed and lacks excellent varieties,especially since the content of emodin is low.Therefore,it is particularly important to carry out germplasm resources evaluation,genetic diversity analysis,and excellent variety cultivation of Polygonum cuspidatum.The genetic diversity and population structure of 52 Polygonum cuspidatum germplasm collected from Hubei,Hunan,Sichuan and Guizhou provinces were analyzed.At the same time,the collected germplasm resources were systematically evaluated from the aspects of morphological characteristics,growth and development traits,physiological and biochemical characteristics,disease resistance,yield traits and medicinal material quality traits.It laid the foundation for the genetic research of Polygonum cuspidatum and provided genetic materials for the cultivation of excellent varieties.The specific results are as follows:(1)MIcro SAtellite identification tool was used to search the Unigene above 1 kb by microsatellite search,and 11848 SSR loci were obtained.Mononucleotide,dinucleotide and trinucleotide are the main repeat types accounting for 54.47%,19.10% and 24.84% of the total SSR,respectively.(2)On the principle of PCR product length of 100-280 bp and primer length of18-27 bp,this study designed primers for the 11848 SSR loci.On this basis,227 pairs of primers with PCR product length of 100-150 bp,primer length of 18-22 bp,GC content of 45%-55%,and Tm value of 59-61℃ were screened.By screening 227 pairs of primers,111 pairs of primers can amplify bands,which are called effective primers;and by screening effective primers,24 pairs of primers can amplify 3 or more loci,which were used to evaluate the genetic diversity of Polygonum cuspidatum.The results of primer polymorphism analysis showed that the number of alleles,polymorphism information content,and Shannon information index of the 24 pairs of primers were 4-16,0.32-0.85,and 0.68-2.20,respectively,indicating that the 24 pairs of primers had high polymorphism.(3)According to the results of genetic diversity analysis,the genetic diversity of germplasm in Fang County is higher,which can provide abundant genetic variation for breeding.Based on the analysis of the genetic structure of Polygonum cuspidatum population,it was found that the genetic differentiation coefficient was 0.025 and the gene flow was 9.908,which indicated that the gene communication was frequent and the genetic variation mainly came from individuals.(4)The 52 Polygonum cuspidatum germplasm had abundant variation in physiological and biochemical characteristics,disease resistance,growth and development,yield and quality of medicinal materials,and the coefficient of variation ranged from 18.84% to 78.89%.The correlation analysis showed that emodin was highly significantly positively correlated with plant height internode length and significantly positively correlated with stem diameter and the correlation coefficients were 0.406,0.515,0.317,respectively,which provided information for breeding varieties with high emodin content.Plant height was significantly positively correlated with rhizome dry weight and polydatin content with correlation coefficients of 0.358 and 0.293,respectively,which indicated that plant height might be an important index of potential elite germplasm.(5)According to the results of traits evaluation,germplasm SCDZ4 had the highest yield(dry weight)(373.5 g),germplasm ESLC6 had the highest polydatin content(31.09mg/g),germplasm ESBD2 had the highest resveratrol content(8.86 mg/g),germplasm HGYS1 and HGYS5 had the highest emodin content(3.68 mg/g),HGYS9 had the highest emodin methyl ether content(11.9 mg/g),and germplasm ESLC6 had the lowest disease index(0.26%).The genetic materials were screened for genetic improvement and breeding of excellent varieties of Polygonum cuspidatum.Based on the grey correlation analysis of yield,polydatin content,emodin content,resveratrol content and emodin methyl ether content,it was found that the germplasm SYFX8 had the highest correlation degree(0.75),indicating that it had good performance in yield and quality of medicinal materials,and had the potential of popularization and utilization in production. |
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