| Bermudagrass (Cynodon dactylon) belongs to Gramineae Eragrostis subfamilychloridoideae (Eragrostoideae) group (Chlorideae), is widely distributed in the world. InChina,Bermudagrass are mainly distributed in the South provinces of the the Yellow Riverbasin, Southern China, central China, southwest, northwest, south of North China. In thisexperiment,150wild bermudagrass (Cynodon dactylon) germplasm resources had beencollected from five natural geographic region in Anhui Province.The150accessions werestudied from morphology and DNA molecular level to explore the genetic diversity, themain results are as follows:1、Ten morphological characteristics of150bermudagrass accessions orginated in An-huiprovince were observed and analyzed to explore their diversity.The results showed that：There were abundant morphological variation among wild bermudagrass accessions.Theirvariation coefficients were ranked as follow：stolon leaf length(36.004%)> height of theerect shoot (35.827%)>internode length of the erect shoot(35.087%)> leaf length of theerect shoot(34.288%)> Stolon internode length（34.008%）>internode iameter of the erectshoot(27.760%)> height of leaf layer(26.962%)>stolon internodediameter(22.256%)>stolon leaf width(19.280%)> leaf width of the erect shoot(17.779%).In the view of different geographical origin, from the mountainous area of South Anhui,Dabie Mountain,The Plain along the Changjiang River, North of Anhui, to Jianghuai Hilly,the height of leaf layer become higher;leaf is longer and wider, internode is longer too.2、There were significant correlations among some of external morphological characters ofwild bermudagrass accessions in Anhui. The plant height was posotively correlated withleaf longth, leaf width, internode length, etc.;3、 In the result of Principal Component Analysis(PCA), the first principal componentcontribution rate was55.01%, the second principal component contribution rate was14.03%, the first two principal component accumulative contribution rate reached69.04%.The first principal component involved leaf length of the erect shoot, stolon leaf length,internode length of the erect shoot, stolon internode length, height of the erect shoot, heightof leaf layer; these indexes related to the length. That is to say, the bermudagrass branches,leaves or whole plant length as the first principal component. In view of second principalcomponent,the load was high in internode iameter of the erect shoot, stolon internodediameter, stolon leaf width, leaf width of the erect shoot;so the second principal componentwas related with width, as the second choices. To distinguish wild bermudagrass externalnutrient characteristics, that plant organ’s height and width should be first considered inidentifying wild bermudagrass external morphological characteristics.4、Based on10morphological characteristics,150accessions were clustered into fivemorphological types in the Euclidean distance of6.5, that is, tall&long-leaf type,coarse-high type, intermedial type,fine-middle type, dwarf-fine type. The distribution ofthe five types is as follow: dwarf-fine type bermudagrass mainly concentrated in The Plainalong the Changjiang River and Dabie Mountain; distribution of fine-middle type mainly concentrated in the mountainous area of South Anhui and Dabie Mountain; intermedialtype bermudagrass widely distributed in Anhui, but mainly concentrated in themountainous area of South Anhui; coarse-high type are mainly distributed in North ofAnhui and Jianghuai Hilly; tall&long-leaf type bermudagrass are mainly distributed inNorth of Anhui.5、The ISSR molecular markers were applied for150wild bermudagrass germplasmgenetic diversity research. A total of8primers amplified243bands,227polymorphicbands, polymorphic ratio was93.42%, the average of each primer amplified30.38bands.6、 POPGENE analysis results showed that: a single population, the proportion ofpolymorphic loci (PPL) ranged from43.21%to68.72%, the average was53.41%; Nei’sgenetic diversity (H) was0.1010~0.1471, the genetic diversity of Shannon’s (I) range of0.1616~0.2411. The overall level of the population, PPL=93.42%, genetic diversity ofNei’s was0.1774, Shannon’s’s information index was0.2961. Study on geneticstructure,Gst=0.2723,27.23%genetic differentiation was between groups;62.77%geneticvariation occurred in the group.It indicated that the genetic diversity mainly occurred in thegroup.Nm=1.3362, the result showed that the gene’s exchange between bermudagrassgroups was weak, which promoted the differentiation.7、In the analysis of genetic distance and genetic identity,5wild Cynodon dactylonpopulation relationship were close, the result was consistent with the bermudagrassgeographic distribution. Based on the UPGMA method, the accessions were divided into3types.The cluster analysis showed that the genetic distance and genetic identity is notcompletely consistent, which was reflected in the differences between the accessionsof Huangshan and Bengbu’s. There are some differences in their environmentalconditions, but the genetic relationship is closer between the two populations. Thissuggests that the genetic diversity of the wild bermudagrass was less influenced byheterogeneity of environment, mainly influenced by genetic material.8、Using NTSYS-pc2.10software to calculate the genetic similarity coefficient of GSranges from0.5802to0.9835。At GS=0.76, the materials are divided into3categories.Thewhole shows bermudagrass in the same area are mostly clustered into one category, theCynodon dactylon from different regions can also be gathered together. The embodiment ofCynodon dactylon germplasm in Huangshan area was the most obvious, whosebermudagrass and Bengbu’s were classified as a class of group classification, which wasreflected in the overall clusterⅡ class. The class Ⅲ also included parts of Huangshanbermudagrass, it suggesting that the geographical boundaries of the Anhui wildbermudagrass germplasm resources was not obvious.9、From the morphological and DNA molecular levels, the clustering analysis were done,the results were not consistent. Differences between molecular markers and morphologicalmay be attributed to the differentiate of specific information provided by each type of tag.Morphological markers reveal the performance of materials, are affected by environmentand very unstable, morphological markers for tests are limited, therefore only reflect partof genetic difference among Cynodon dactylon germplasm. ISSR technology is at the molecular level, reveals the difference of genotype, is to explore the genetic variation fromthe genetic material DNA angle and can reveal more genetic information. Two methodscome from different levels and angles, cannot replace each other, but can be combined witheach other, can clarify the comprehensive classification. |
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