Genetic Diversity And Population Structure Analysis Of Eggplant (Solanum Melongena L.) Germplasm Resources

Eggplant(Solanum melongena L.) originated from the Indian and Southeast Asian tropical regions and was introduced to China between the4th and5th centuries. As a self-pollinated crop and perennial shrub in tropical and subtropical regions, eggplant is usually planted as an annual herb. China, with a long history of eggplant cultivation, is recognized as the secondary origin of eggplant and has rich eggplant germplasm resources. At present, China has become the world’s largest eggplant production and consumption country. The research on the genetic diversity of eggplant germplasm resources would benefit the genetic resources conversation, core collection construction and genetic improvement of eggplant. In this study, the genetic diversity of70eggplant accessions was assessed by using morphological marker and SRAP (Sequence-Related Amplified Polymorphism) markers. The main results from Principal Component Analysis (PCA), Clustering Analysis (CA) and Population Structure Analysis (PSA) were as follows:The selected28morphological characteristics demonstrated that there were rich morphological diversities among germplasm; moreover, it was discovered that different materials and traits had different regions of genetic diversity. According to the genetic distance of germplasm,70eggplant materials were divided into7groups. The most clustered results were consistent with the morphological traits, while only a few parts were in confusion due to possible environmental factors. In succession, the morphological data were analyzed by the PCA with SPSS software.9characteristic roots (>1) were obtained and the total contribution rate was76.297%. In addition, the28morphological characteristics could be simplified to17characteristics, covering the majority of information.To explore the genetic basis of eggplant germplasm, the genetic diversity was analyzed by using the SRAP molecular marker.375distinct PCR bands were amplified from a total of21primers, and17.8bands per primer were amplified. Among the amplified375bands,72bands were polymorphic, and the polymorphic rate was19.2%. The genetic similarity coefficients among these germplasm ranged from0.3889to0.9583, with the average of0.7053. The results suggested that there existed genetic diversity among the eggplant germplasm; however, the genetic diversity was a bit narrow. Based on the genetic similarity coefficients, the clustering analysis of70eggplant materials was conducted by using the Unweighted Pair Group Method with Arithmetic mean (UPGMA). The results showed all the tested eggplants were classified into six groups at the similarity coefficient of0.72. Consequently, we suggest the clustering analysis with SRAP markers is more reflective on demonstrating materials’genetic relationship.The result of population structure analysis indicated that eggplant materials could be divided into five subgroups. Comparing this result to the clustering analysis with SRAP, we found the consistency in the materials with single genetic components (84.29%); however, differences appeared among the materials with mixed genetic components (15.71%). It suggests a possible existence of gene flow among the different eggplant groups. Accordingly, the breeders should consider not only the genetic relationship but also the genetic structure in the breeding process.