Background and History

The C.M. Rick Tomato Genetics Resource Center (TGRC) is a genebank of wild relatives, monogenic mutants and miscellaneous genetic stocks of tomato. The wild species group includes representatives of all nine Lycopersicon species, as well as 4 related Solanum species. The monogenic mutants include spontaneous and induced mutations affecting many aspects of plant development, introgressed disease resistance genes, and protein marker stocks. Other miscellaneous stocks includes linkage testers, trisomics, tetraploids, translocations, landraces, and various types of stocks containing alien chromosomes, or segments thereof, introgressed from selected wild species.

The collection was founded by the late Dr. Charles M. Rick in the Dept. of Vegetable Crops, UC-Davis, who collected many of the wild species accessions and produced a large proportion of the marker and cytogenetic stocks. Over time, many other researchers contributed germplasm to the TGRC, resulting in one of the world's most comprehensive collection of genetic stocks and wild relatives of tomato.

The TGRC is a unit of the Department of Plant Sciences, University of California at Davis, and is part of the National Plant Germplasm System (NPGS). Financial support is provided by UC-Davis, USDA, the California Tomato Research Institute, California Tomato Commission, and the TGRC endowment.

TGRC Activities

Germplasm Acquisition

In order to keep abreast of changes in research methods, the development of novel genetic tools, etc, we acquire new accessions from various sources, including donations from other researchers, collecting trips in the native region, and TGRC research activities.

Stock Maintenance 

Seed samples of all accessions are stored in a local seed vault for short term storage and active use; subsamples are deposited with the National Seed Storage Laboratory for long term storage and backup. Germination tests are performed regularly to ensure a minimum of 80% viability. For seed regeneration, plants are grown in the greenhouse or field, during which time they are observed for key features, including morphological markers, cytogenetic changes, genetic diversity, mating systems, etc.

Seed Distribution 

Seed samples are distributed gratis to bona-fide researchers worldwide. Each year, we receive over 200 requests, in response to which we send out over 3,000 individual seed samples representing approx. 1,500 unique accessions.


TGRC seed samples are used for a wide variety of basic and applied research projects. Our annual survey of the literature identifies approx.100 published reports each year which mention use of TGRC stocks. An area of intense activity is the search for new disease resistances in the wild species. Other traits of economic interest include insect resistance, abiotic stress (drought, heat, cold, salinity) tolerance, and improved horticultural and fruit characteristics. Topics of a more fundamental nature include a wide variety of studies in physiology and development (e.g. leaf development, fruit ripening, self-incompatibility, etc), genetics (e.g. mapping, QTL studies, wide hybridization, etc), and genomics (e.g. map-based cloning, comparative sequence analysis, etc). 


Our database includes passport information on all accessions, detailed collection notes for wild species, a list of the known mutants of tomato, and a library of digital images of tomato stocks. Lists of available stocks are published annually in the Tomato Genetics Cooperative Report, or can be downloaded directly. 

Research Projects

The broad objective of TGRC research is to improve the availability and accessibility of tomato germplasm. Some of our current projects include:

  • Introgression of the Solanum lycopersicoides and S. sitiens genomes into cultivated tomato.
  • Patterns of homeologous chromosome pairing and recombination in derivatives of these species.
  • Genetic diversity and crossing relationships in L. chilense.
  • Genetic Analysis of Fruit Antioxidant Accumulation

Recent Publications