Assessment of genetic diversity of Camellia yuhsienensis based on leaf structure and ISSR markers

Abstract

Genetic diversity of Camellia yuhsienensis was analyzed according to leaf structure and molecular markers to determine genetic relationships and genetic differentiation characteristics among various strains. Leaf structural traits and ISSR molecular markers were selected to study the genetic diversity and cluster analysis of C. yuhsienensis. Twenty-one leaf traits varied to different degrees, and variation coefficients ranged from 6.91–20.45%. They all reached significant or extremely significant levels. Through principal component analysis, the cumulative contribution rate of the first four principal components reached 85.57%, and eight typical leaf characteristics were screened out. Molecular markers revealed that 201 loci were amplified by 10 ISSR primers, and 175 were polymorphic loci with an average polymorphism rate of 87.06%. Nei's Diversity Index and the Shannon diversity index values were 0.2613 and 0.4013, respectively. An ISSR identification card drawn using primer 826 was used to identify 13 C. yuhsienensis. Cluster analysis demonstrated that the clustering results based on leaf structure and molecular markers were generally consistent. Only CL1 and CL2 differed between the two methods, and the ISSR molecular markers detected small variations at the molecular level. Therefore, the clustering was more detailed than that of leaf structural traits. In the two clustering methods, germplasms with higher phloem thickness and main vein bulge and a short diameter of the vascular bundle were clustered into one category, and the specific germplasm LY2 was clustered into another category. Our results provide a theoretical basis for the diversity, germplasm identification, and rational utilization of C. yuhsienensis.