Wild species• 17 species of tomatoes and their wild relatives

Mutants • Mostly single gene mutations• Induced and spontaneous

Miscellaneous genetic stocks• Introgression lines • Landraces

A collection of genetic stocks and wild relatives of tomato

C. M. RickC. M. Rick

T G R CT G R CTomato Genetics Resource CenterTomato Genetics Resource Center

Total ≈ 3,600 accessions

Wild Species• From Columbia to Chile

• Also the Galapagos Islands

• Ranges overlap

S. chilense

Moyle 2008 Evolution

Extreme Xerophytes

• grafting allows growth in the greenhouse

S. sitiens

The Atacama Desert – one of the driest places on Earth

Wet Conditions

(photo C. Rick)

S. ochranthum on a stream bank S. juglandifolium seedlings

Galapagos Island Species

Little or no morphological variation

S. cheesmaniae accessions

Charley Rick

Variation within SpeciesS. peruvianum fruit from a single population

photo C. Jones

Valuable Traits in Wild Species

• Bacterial and fungal resistance • Gemini virus resistance

• Drought and salinity tolerance• Cold tolerance and insect resistance

S. lycopersicoides, grows to 3,600m in Andes of S. Peru and N. Chile

(photo C. Jones)

Mutants in Cultivated Tomato

• Leaf morphologies and colors• Growing habits• Hormone deficiencies• Floral differences: i.e. male steriles

“Lazy” “Ghost”

“Lanata, Wooly” “Curl”

Some mutations are lethal or sterile in the homozygote and must be maintained through the

heterozygote

“double dwarf”

“extreme dwarf”

Pollinations

“Buzz” pollinating Hand pollinating

• Tailored to the mating system: outcrossers and selfers

• 50 plants/accession grown for outcrossers

Germplasm Evaluation

Germination Testing

Purity, Identity & Diversity

Seed Regeneration

Seed Processing

• Fruit is blended and fermented for 48 hours

• Seeds are flattened on paper to dry

• Packaged and placed in storage

Seed Storage

• Working collection stored at 6°C

• Germ tested after 10 years

• Long term seed stored at -20°C

USDA TGRC

Seed DistributionAnnual activity•300 - 500 requests from researchers in over 30 countries•approx. 5,000 seed samples distributed•utilization rate of ~ 100%•seed provided gratis

Common uses•breeding•genetics and genomics • leaf development• fruit ripening• fruit biochemistry•evolutionary studies•education

Threats to Wild Tomatoes in Native Area

agriculture urbanization

herbivores mining

Department of Plant Sciences

tgrc.ucdavis.edu