Roger T. Chetelat

Associate Geneticist
Director, C.M. Rick Tomato Genetics Resource Center
tel (office): 530-752-6726
TGRC: 530-754-6059
lab: 530-754-8647
FAX: 530-752-9659


Ph.D. - University of California, Davis, Genetics, 1994
M.S. - University of California, Davis, Plant Physiology, 1983
B.S. - Santa Clara University, Biology, 1979

Professional Experience

Associate Geneticist, Department of Plant Sciences, UC Davis, 2002 - present
Assistant Geneticist, Department of Vegetable Crops, UC Davis, 1995 - 2001
Staff Research Associate, Department of Vegetable Crops, UC Davis 1990 - 1994
Research Associate, Campbell Soup Co., Davis 1985 - 1990


My research program focuses on the genetics and germplasm resources of tomato and its wild relatives. One research objective is to expand the genetic base of tomato through hybridization and introgression with related nightshade (Solanum) species.  Towards this goal, we synthesize introgression lines and other genetic stocks that incorporate alien chromosomes or segments in the background of cultivated tomato.  Comparative genetic maps of the nightshade genomes are used to study structural evolution in the genome and clarify phylogenetic relationships.  Another research goal is to ameliorate the low rate of chromosome pairing and recombination between alien genomes in the tomato × nightshade hybrids.  By altering the expression of genes in the DNA mismatch repair system, we study their functions in homeologous recombination and potential practical applications for facilitating gene transfer from wild relatives into crop plants.   Unilateral and self-incompatibility, two reproductive barriers that control illegitimate outcrossing and prevent selfing, are another research interest.  We are working towards the map-based cloning of a QTL controlling pollen reaction in wide crosses that interacts with the S-locus.   

These research projects support the mission of the C.M. Rick Tomato Genetics Resource Center (TGRC), a genebank of over 3,600 accessions of wild species, mutants, and other genetic stocks of tomato. The wild species includes representatives of all the wild tomatoes (the Lycopersicon clade), as well as 4 closely allied Solanum species. We study the distribution of genetic variation (biodiversity) within and among wild populations of these taxa, as well as their mating systems and crossing relationships, in order to optimize seed regeneration methods and design core subsets of the collection. The mutant collection includes spontaneous and induced mutations affecting most aspects of plant development. Other  genetic and cytogenetic stocks maintained by the TGRC include misc. marker combinations, linkage tester stocks, trisomics, tetraploids, translocations, landrace varieties, introgression lines, chromosome substitutions and additions, etc.

Selected references

Ji, Y., and R.T. Chetelat (2007) GISH analysis of meiotic chromosome pairing in Solanum lycopersicoides introgression lines of cultivated tomato. Genome 50: 825-833.

Jones, C.M., C.M. Rick, D. Adams, J. Jernstedt, and R.T. Chetelat (2007) Genealogy and fine mapping of obscuravenosa, a gene affecting the distribution of chloroplasts in leaf veins, and evidence of selection during breeding of tomatoes (Lycopersicon esculentum; Solanaceae).  Amer. J. Bot. 94: 935-947.

Canady, M.A., Y. Ji, and R.T. Chetelat (2006) Homeologous recombination in Solanum lycopersicodes introgression lines of cultivated tomato.  Genetics 174: 1775-1778.

Rousseaux, C.M., C. M. Jones, D. Adams, R. Chetelat, A. Bennett and A. Powell (2005) QTL analysis of fruit antioxidants in tomato using Lycopersicon pennellii introgression lines. Theor. Appl. Genet. 111: 1396-1408

Canady, M.A., V. Meglic, R.T. Chetelat (2005) A library of Solanum lycopersicoides introgression lines in cultivated tomato.  Genome 48: 685-697.

Ji, Y., R.A. Pertuze, R.T. Chetelat (2004) Genome differentiation by GISH in interspecific and intergeneric hybrids of tomato and related nightshades. Chrom. Res. 12: 107-116.

Guimaraes, R.L., R.T. Chetelat, and H.U. Stotz (2004) Resistance to B. cinerea in S. lycopersicoides is dominant in hybrids with tomato, and involves induced hyphal death. Eur. J. Pl. Path. 110: 13-23.

Pertuze, R. A., Y. Ji, and R.T. Chetelat (2003) Transmission and recombination of homeologous S. sitiens chromosomes in tomato. Theor. Appl. Genet. 107: 1391-1401.

Ji, Y., and R.T. Chetelat (2003) Homoeologous pairing and recombination in Solanum lycopersicoides monosomic addition and substitution lines of tomato. Theor. Appl. Genet. 106: 979-989.

Pertuze, R. A., Y. Ji, and R. T. Chetelat (2002) Comparative linkage map of the Solanum lycopersicoides and S. sitiens genomes and their differentiation from tomato. Genome 45: 1003-1012.

Stamova, B. S., and R. T. Chetelat (2000) Inheritance and genetic mapping of cucumber mosaic virus resistance introgressed from Lycopersicon chilense into tomato. Theor. Appl. Genet. 101: 527-537.

Chetelat, R.T., and V. Meglic (2000) Molecular mapping of chromosome segments introgressed from Solanum lycopersicoides into cultivated tomato (Lycopersicon esculentum). Theor. Appl. Genet. 100: 232-241.

Chetelat, R.T., V. Meglic, and P. Cisneros (2000) A genetic map of tomato based on BC1 Lycopersicon esculentum x Solanum lycopersicoides reveals overall synteny but suppressed recombination between these homeologous genomes. Genetics 154: 857-867.

Chetelat, R.T., C.M. Rick, P. Cisneros, K.B. Alpert, and J.W. DeVerna (1998) Identification, transmission, and cytological behavior of Solanum lycopersicoides Dun. monosomic alien addition lines in tomato (Lycopersicon esculentum Mill.). Genome 41:40-50.

Chetelat, R.T., P. Cisneros, L. Stamova, and C.M. Rick (1997) A male-fertile Lycopersicon esculentum x Solanum lycopersicoides hybrid enables direct backcrossing to tomato at the diploid level. Euphytica 95:99-108.

Chetelat, R.T., J.W. DeVerna, and A.B. Bennett (1995) Introgression into tomato (Lycopersicon esculentum) of the L. chmielewskii sucrose accumulator gene (sucr) controlling fruit sugar composition. Theor. Appl. Genet. 91:327-333.

Chetelat, R.T., E. Klann, J.W. DeVerna, S. Yelle, and A.B. Bennett (1993) Inheritance and genetic mapping of fruit sucrose accumulation in Lycopersicon chmielewskii. Plant J. 4:643-650.

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