Nuclear SSR-based genetic diversity and STRUCTURE analysis of Greek tomato landraces and the Greek Tomato Database (GTD)

Abstract

Tomato has been cultivated in Greece for more than 200 years, even though is not native to the country. Greece with a favourable environment all-round the year, has become a major competitor in tomato production around Europe. However, there is an increasing demand to improve tomato crop, to withstand harsh environmental conditions (extreme temperatures, salinity, etc.), and to develop high-quality final products. People have devoted a significant effort to crop improvement through phenotypic screening resulting in a large number of tomato landraces. An increasing demand to clarify the relationships among local tomato landraces and hybrids utilizing the most preferred molecular markers the simple sequence repeats (SSR-markers) is the main objective of this study. Twenty-seven tomato landraces and two tomato hybrids cultivated in Crete, Greece, were genotyped utilizing eleven simple sequence repeats (SSR) along with the Structure analysis of the germplasm. A neighbour-joining dendrogram of the 27 landraces and the two hybrids was produced. The Structure analysis indicated that nine ancestral populations are hidden inside the group of all the genotypes tested, using Evanno's method. The final objective was to make these data publicly available through the first Greek relational database (Greek Tomato Database-GTD). GTD was developed allowing the users to update and enrich the database, with new and supplemental information. This work is the first molecular fingerprint of the 27 landraces of Greece which is documented along with the phenotypic information in the GTD.