Association Analysis Of Important Agronomic Traits Of Stevia Rebaudiana Bertoni

Stevia rebaudiana Bertoni is a new economic crop rich in glycosides,Asteraceae perennial herb,commonly used in food and pharmaceutical industries[161].Stevia rebaudiana Bertoni is an advantageous industry for China’s export earnings and improvement of people’s lives.China’s Stevia rebaudiana Bertoni has a large area of cultivation and is a world’s largest exporter.The leaf yield and quality of Stevia rebaudiana Bertoni are the decisive factors in determining the quality of Stevia rebaudiana Bertoni.The current hotspot of Stevia rebaudiana Bertoni breeding is still the selection of good high glycoside stevia lines.DNA molecular markers are emerging genetic markers.Compared with morphological,cellular and protein markers,they are characterized by rapidity,simplicity,low cost,high genetic polymorphism and good repeatability.They have been widely applied to the genetic diversity of various crops.Analyze and assist in selecting target markers to assist in breeding and other areas.Mastering stevia genetic material and understanding the genetic basis of its agronomic traits contribute to the optimization of stevia lines.Therefore,the analysis of the association between important agronomic traits of stevia plays an important role in the development of the important agronomic trait genes for Stevia rebaudiana and for genetic assisted breeding of stevia DNA molecules.In this paper,natural populations of Stevia rebaudiana Bertoni are used as research materials,and statistical analysis of the main agronomic traits of Stevia rebaudiens-descriptive,simple correlation and partial correlation analysis,principal component analysis and cluster analysis,EST-SSR marker genetic diversity and inter-population heritability.Based on the above analysis,the relationship between EST-SSR markers and agronomic traits was analyzed and the EST-SSR markers of important agronomic traits were obtained[162 165].The following important results were obtained:1.Analysis of agronomic traits of Stevia rebaudiana Bertoni:The results showed that the variability of these 11 traits was larger,the coefficient of variation of dry weight was the largest,the coefficient of variation was 119.49%,followed by the number of branches and STV,and the coefficient of variation was between 53.34%and 69.99%.The plant height,stem diameter,number of nodes,RA,RC,RD,total2.glycosides,and RA/total glycoside variation coefficient were all less than 35%.It was clarified that there was a large difference in the phenotypes of association analysis of stevia,and they were rich in diversity and could be sweet.Ye chrysanthemum breeding provides sufficient breeding data[162].Correlation and partial correlation analysis showed that:dry weight and plant height,stem diameter,branches and the number of sections showed a very significant positive correlation,so you may wish to choose tall plants with luxuriant foliage to establish high-yield stevia varieties;RA and stem There was a significant positive correlation between weights and a very significant negative correlation with STV.Therefore,the selection of good Stevia varieties should properly handle the relationship between RA and STV.Selecting the Euclidean distance at 5.0,93 stevia lines can be clustered into 5 categories.The principal component analysis shows that the cumulative contribution rate of the four eigenvalues reaches 85.945%,and it is believed that these four principal components can summarize most of the relevant information.3.DNA genetic diversity analysis:Genetic diversity analysis of 93 stevia materials revealed that 58 pairs of EST-SSR primers amplified 10,532 alleles from 93 materials with a polymorphism of 91.38%.The site has an average of 18.1 alleles.It shows that the genetic diversity of the associated population is large and can be used for correlation analysis.The results of cluster analysis showed that when the Euclidean distance was 14,all Stevia materials were divided into five major groups.Comparing the two clustering results,the clustering results based on EST-SSR molecular markers indicated that most Stevia species with the same genetic background were a single species;however,in the clustering of apparent traits,the genetic background of stevia species was different.Inferences also converge in the same category.4.GWAS analysis of important agronomic traits of Stevia:Using the general linear model in TASSEL 5.0 software,principal component analysis to evaluate population structure as a covariate,GWAS analysis of 11 agronomic metrics of 93 stevia lines,obtaining 10 and 6 agronomic traits The indicators(plant height,stem diameter,number of nodes,RD,STV,total glycosides)were significantly associated5.with EST-SSR markers at the 0.01 level,demonstrating that EST-SSR markers can be used for the cluster analysis of 93 stevia resources.