Thomas M. Gradziel

Thomas Gradziel

Position Title

  • Faculty
UC Davis, One Shields Ave, Davis CA 95616


  • Ph.D., Cornell University; Plant Breeding, 1987
  • M.S., Cornell University; Plant Breeding, 1980
  • B.S., University of Massachusetts Amherst; Plant Science, 1977

Research interests and expertise: 

Research focuses on the genetic improvement of almond and peach. Strategies employed include wild germplasm characterization, preservation and introgression, intra-and inter-specific hybridization, marker assisted selection, and epigenetic manipulation. Breeding objectives include developing productive, high market quality varieties and rootstocks which combine the traditional as well as novel traits required to meet emerging grower, processor and market demands, including high productivity, improved disease/pest resistance and reduced labor inputs.

Current projects: 

  • Almond Breeding (Almond Board of California)
  • Rootstock Breeding (Almond Board of California, IAB SCRI,
  • Processing Peach Breeding (California Caning Peach Association, SCRI,

Current teaching: 

  • Agriculture, Nature and Society; PLS 1 (fall quarter)
  • Fruit and Nut Cropping Systems; PLS 170A (fall quarter, alternate years)
  • Fruit and Nut Cropping Systems; PLS 170B (spring quarter, alternate years)
  • Agroforestry; PLS 160 (fall quarter, alternate years)

Outreach and Extension:

Recognizing that a critical component of successful cultivar development is the long-term, rigorous testing of advanced breeding selections under regional grower conditions, I work closely with farm advisors, extension specialists, nurserymen, growers, and processors to benefit from their extensive expertise.

External activities that contribute to scholarship:

  • National Prunus Crop Germplasm Committee: Almond, Chair
  • International Society of Horticultural Sciences: Almond Working Group, Chair
  •  California Fruit and Vegetable Processing Advisory Committee

Prizes, Awards, Honors:

  • L.D. Davis Endowed Chair for Tree Crop Breeding, 1994-present

Google Scholar: under development


  • Almond
  • Peach
  • Rootstocks
  • Genetics
  • Breeding
  • Self-incompatibility
  • Disease resistance
  • Interspecific introgression
  • Genetic aging
  • Epigenetic selection