Genetic Diversity of Eggplant Revealed by SSR Markers

Eighty eight accessions including eighty six of Solanum melongena and two wild related species (Solanum integrifolium and Solanum torvum) were used to analyze the genetic variation with 23 SSR primers. And 20 primers were successfully amplified, of which 19 showed polymorphism with a total of 68 detected alleles. The number of alleles per primer ranged from 2 to 6, with a mean of 3.6. Among 19 polymorphism primers, four primer pairs (EM117, EM155, EM126, EM127) gave rise to multiple polymorphic bands, two of which could be used for varieties certification of eggplant. The average genetic diversity of all accessions measured by the Nie´s genetic diversity, Shannon´s Information index and Effective number of alleles were 0.41(range 0.12~0.80), 0.7443(rang from 0.2617~1.6958) and 2.0151(ranged from 1.1307~5.310), respectively. Genetic similarity among all the accessions ranged from 0.09 to 1 with an average of 0.69. The high diversity was displayed. Additionally, S. melongena had high average similarity with the wild species S. integrifolium (0.61) and low average similarity with S. torvum (0.26). UPGMA clustering at genetic similarity value of 0.60 grouped all the eggplant accessions into four groups, where S.torvum formed a separate and more distant cluster. Moreover, the fourth group can be further classified into two sub-groups, and the wild species S. integrifolium can be clearly separated from the other cultivated eggplants. However, majority of the cultivated eggplants were not clustered in ways concordant with taxonomic information such as collection sites, fruit shape or any other known trait. The genetic diversity and phylogenetic relationships of eggplant accessions reported in this study might be used for breeder when planning future crosses between cultivated eggplant and the wild species.