EVALUATION OF CULTIVATED TOMATO GERMPLASM RESOURCES

Lack of germplasm resources has severely limited genetic improvement of tomato (Solanum lycopersicum) in China. To potentially solve this issue, a total of 127 cultivated tomato accessions were introduced from the United States, Department of Agriculture (Geneva, NY, USA). These accessions have been disseminated to North America from Europe by a different route than the cultivated tomatoes in China, and have a different genetic background. A phylogenetic tree was drawn using 47 morphological markers, and a core germplasm collection comprising 20 tomato accessions was identified. Important quality traits such as fruit size, carotenoid levels, total soluble solids (TSS), fruit color and fruit softness were further examined in this core tomato germplasm collection. The results provide valuable information about this breeding material for genetic improvement of tomato in China. In order to save time and labor during the evaluation of the tomato germplasm resources, principal component analysis (PCA) was used to reduce dimensionalities, and it was found that the first 14 principal components contributed to 72.18% of the 47 phenotypes in the 127 tomato accessions. If the analysis of the core germplasm collection and the PCA analysis were used to evaluate other tomato germplasm resources, it could enhance breeding, and in addition it could also provide an important reference for evaluation of germplasm resources in other crops.