| Atractylodis Rhizoma is a commonly used medicinal materials,the base source of which is the perennial herbs Atractylodes lancea(Thunb.)DC and Atractylodes chinensis(DC.)Koidz of the genus Atractylodes in the family Asteraceae.At present,wild Atractylodes resources are on the verge of extinction,while the production of Atractylodes is mainly based on rhizomes as propagation material,and long-term asexual reproduction leads to serious degradation of germplasm,serious pests and diseases,and yield and quality are reduced to different degrees.In particular,the content of atractylodin in Atractylodes lancea(Thunb.)DC is reduced,about 50%～70% cannot reach the pharmacopoeia standard(0.3%),which seriously restricts the development of Atractylodes industry.In this study,we collected germplasm resources of Atractylodes from 72 regions across China,established Atractylodes germplasm resource nursery,and on this basis,selected 224 strains with more significant morphological differences,and carried out the evaluation of Atractylodes germplasm resources and preliminary construction of core germplasm in terms of morphology,morbidity,yield and herb quality,etc.The main findings are as follows:(1)Twenty-one morphological traits,including stem color,leaf margin,plant height,and number of buds,were measured in different Atractylodes germplasm,and their genetic diversity index,broad-sense heritability and coefficient of variation were calculated.The results showed that the genetic diversity indices of ten quality traits ranged from 0.55 to 1.06,with relatively large variation.The genetic diversity indices H’of four quantitative traits,namely,stem color(1.06),leaf margin(1.04),leaf tomentum(0.96)and leaf shape(0.91),ranked in the top,indicating that these four quality traits had high genetic diversity and distribution frequency in Atractylodes germplasm resources,while the genetic diversity index H’ of stem shape was only 0.55,which was less diverse.The broad-sense heritabilities of leaf length,leaf width,plant height,internode length and branch length were all above 70%,indicating that these five traits were highly influenced by genotype;the coefficients of variation of five traits,including basal stem thickness,middle stem thickness,plant height,internode length and branch length,were all greater than 10%,indicating that their degrees of variation were higher and their inheritance was more unstable.Twenty-one morphological traits were subjected to correlation analysis and principal component analysis,and the results showed that there were 61 pairs of highly significant correlations(p<0.01)and 21 pairs of significant correlations(p<0.05)among morphological traits,among which,leaf width and internode length,stem branching,number of stem first-level branches and leaf fissures,plant height and central stem thickness all had highly significant positive correlations,which were consistent with the results of principal component analysis.(2)To investigate the occurrence of black spot disease in different Atractylodes germplasm and conduct statistical analysis.The results showed that there were differences in the incidence of disease among different germplasm.From the rate of diseased leaves in June,YF-2,YF-4 and LJS-2 germplasm had a lighter incidence with only 2.33% to 3.49% of diseased leaves,while HBCD-2,HBCD-3,MF-1 and BK-2germplasm had a heavier incidence with more than 90% of diseased leaves.There were also differences in the incidence of disease among the five types of Atractylodes: wild A.chinensis,cultivated A.chinensis,wild A.lancea,and cultivated A.lancea,Hybrid Atractylodes.In terms of the rate of diseased leaves in June,the rate of diseased leaves in cultivated A.chinensis was significantly higher than that in cultivated A.lancea,and there were no differences among the other types.Correlation analysis was performed with 21 morphological traits,and the results showed that both diseased leaf rate and disease index in June and July showed significant negative correlations with plant height,internode length,and central stem thickness,with correlation coefficients ranging from-0.145 to-0.329.(3)The single plant yields of different Atractylodes germplasm were investigated and statistically analyzed.The results showed that there were differences between different germplasm in the fresh weight of single rhizomes and fresh weight of roots,which ranged from 2 g to 85 g and 0.5 g to 21.5 g,respectively.The fresh weight of the roots of two germplasm,SST-1 and YF-4,was larger than 80 g.The fresh weight of the roots of four germplasm,GZKL-2,WJJ-2,JFL-1,and LTX-HPC-2,was the smallest at 2 g.The fresh weight of the roots of DF-3,YF-4,and LTX-WJF-1 was larger than 17 g.The fresh weight of the roots of five germplasm,WJJ-2,JFL-1,and KFXYC-1,was only 0.5 g.The fresh weight of the roots of five germplasm such as WJJ-2,JFL-1 and KFXYC-1 was only 0.5 g.There were no significant differences between the single plant yields of the five types of Atractylodes: wild A.chinensis,cultivated A.chinensis,wild A.lancea,and cultivated A.lancea,Hybrid Atractylodes.Correlation analysis was performed with 21 morphological traits,and the results showed that both single rhizomes fresh weight and root fresh weight showed highly significant positive correlations with root number,number of buds,internode length,and leaf length,with correlation coefficients ranging from 0.236 to 0.679.(4)The species and contents of the compounds in different Atractylodes germplasm were determined by GC-MS and analyzed qualitatively and quantitatively.The results showed that the types and contents of the compounds differed among different Atractylodes germplasm and different tissue parts.There are more types of compounds with low boiling points in the roots,mainly Isocomene,α-Gurjunene,β-Isocomene,Caryophyllene;while the rhizome is mainly dominated by compounds with high boiling points,such as Eleme,Guaiol,Hinesol,β-Eudesmol,α-Eudesmol.The total amount of the four components in the rhizomes,namely,Hinesol,β-Eudesmol,Atractylone,and Atractylodin,ranged from 0.42% to 32.45%,and the total amount of these four components in the roots ranged from 0.14% to 1.41%.The analysis of the types and contents of compounds in the rhizomes of Atractylodes germplasm from different regions revealed that the samples of Atractylodes germplasm from southern regions such as Anhui,Hubei,and Guizhou contained higher contents of Hinesol and β-Eudesmol,with the highest content of Hinesol from Huanggang Qi Chun region with a mean value of10.78% and the highest content of β-Eudesmol from Huanggang Hong’an region with a mean value of 2.61%,while those from northern regions such as Hebei were dominated by Atractylone and Atractylodin was dominant.Correlation analysis was performed with21 morphological traits,and the results showed that both rhizomes and roots showed a significant negative correlation between Atractylodin content and leaf width,with correlation coefficients of-0.267 and-0.229,respectively.(5)In this study,224 Atractylodes germplasm were evaluated using the information entropy assignment method based on the occurrence of black spot,fresh weight of rhizomes and the content of Atractylodin in rhizomes,and seven germplasm with better overall characteristics,including YF-4,SST-1,MC-LZM-1,YF-1,TDG-2 and LDLC-1,were selected.(6)In this study,Core Hunter 3 was used to construct the core germplasm,and it was found that the ranges of the five parameters of maximum,minimum,mean,variance,and coefficient of variation of each phenotype in the constructed core germplasm library were not significantly different from those in the original germplasm library,and the regional distribution of samples could cover almost the entire original germplasm library.After adding one germplasm from Hebei,the core germplasm library of Atractylodes included30 copies of NMG-HLBE-1,GZKL-2,THX-WTC-2,THC-2,LY-3,and WJJ-3. |
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