Analysis Of Genetic Diversity In Eggplant(S. Melongena L.) Germplasm Resourse

Eggplant (S. melongena L.) origined from South-East Asia, India, Burma and the tropics area nearby, it had a long time of culture history, and very rich in germplasm resources in China.The study on the genetic diversity of eggplant germplarsm resources can benefit the conservation, classification, identification, genetic enhancement and effective utilization of the eggplant germplasm resources. Molecular marker, which can detect the genetic diversity at DNA level, is a powerful tool to study genetic diversity. RAPD markers have been popularized for their simplicity, rapidity and non-specialty among different genera. In this study, the genetic diversity in 53 eggplant germplasms from different countries or regions was assessed using morphological characteristics and RAPD markers, and the genetic relationship among the germplasms was revealed by cluster analysis at various level. The main results were as follows:1. The genetic diversity among 53 eggplant germplasms was revealed by cluster analysis on 24 morphological characteristics. The euclidean distance of germplasms varied from 80 to 15590, and the average was 2058, it suggested that the genetic diversity among germplasms was wide. Clustering analysis indicated that 53 germplasms could be divided into three groups: 30 germplasms classified into group 1, group 2 had 16 germplasms, and group 3 had 13 germplasms. Clustering analysis on morphological characteristics was not very consistent with traditional classification on fruit shape, and not associated with geological distribution too.2.The technique of eggplant DNA extraction was established: with fresh young leaves, using the developed CTAB method, some measures were taken to prevent oxidation of phenolic compounds by adding a proper amount of PVP during grinding, and DNA sample extracted by the methods had high purity.3.Optimized RAPD reaction system and suitable conditions were obtained: 1×buffer, 150μmol/L dNTP, 2.2 mmol/L Mg²⁺, 1 U Taq DNA polymerase, 0.4μmol/L primer, 30ng template DNA; reaction condition: 92℃5min; 92℃1min, 38℃1min, 72℃1min, 45 cycles; 72℃, 8min。 4. The genetic diversity among 53 eggplant germplasms was analyzed by RAPD (Random Amplified Polymorphic DNA). 80 primers were used for amplification, among which 9 primers were selected for RAPD analysis. These primers could amplify stable and polymorphic RAPD bands, and produced 81 bands. Of them, 46 bands (56.79%) were polymorphic. The genetic similarity indexes of all the germplasms varied from 0.57 to 0.99, suggesting that the genetic diversity among germplasms was narrow. The dendrogram constructed using the UPGMA analysis suggested that 53 germplasms could be divided into six groups: 29 germplasms classified into group 1, group 2 had 2 germplasms, group 3 had 3 germplasms, group 4 had only 1 germplasm, 4 germplasms classified into group 5, others classified into group 6. Clustering analysis on RAPD markers was not fully corresponded with traditional classification on fruit shape, and not associated with geological distribution too.5. Clustering analysis between morphological characteristics and RAPD markers was not very consistent. The former expressed the phenotype difference, accepting the interaction between genotype and Environment, inheritance and expression may not very stable, plant morphology and physiology characteristic maybe changed; the latter expressed the entire information of the hereditary geneome, and the result was true and reliable.