Genetic Diversity and Population Structure of Asian Tomato Accessions Based on Simple-Sequence Repeats

Tomato (Solanum lycopersicum L.) is one of the most economically important plants in the family Solanaceae. Understanding its genetic diversity of accessions is vital for additional collection of tomato germplasms. The objective of this study was to determine the genetic diversity and population structure of 355 tomato accessions from Asia using 18 simple-sequence repeats (SSRs). A total of 176 alleles were detected at an average of ten alleles per SSR locus. The average major allele frequency and polymorphic information content were 0.69 and 0.39, respectively. Model-based structure analysis revealed two subpopulations (88%), including admixtures (11%) in the 355 Asian tomato accessions, consistent with clustering results based on genetic distance. The overall FST value was 0.135, indicating a moderate differentiation between the inferred subpopulations. Analysis of molecular variance showed that the genetic variance among geographical groups was less than 6%, in contrast to 86% of genetic variance among individuals. The results from this study will provide important information for future germplasm conservation and improvement programs for tomato.