Tomato Genetics and Breeding Program  

 Our Mission                      

Our long-term research goal is to understand the genetic processes that are under selection during the domestication of plants and the breeding of elite varieties.  We leverage emerging DNA sequence data and comparative biology to gain insight into the differences that occur within domesticated germplasm and the fundamental genetic changes that have been imparted through targeted selection in plant breeding.  We apply tools and knowledge from these studies to the conservation of genetic resources and the development of new plant varieties with increased disease resistance and nutritional quality.

A primary goal of our plant breeding research is to more clearly define the genetic basis of field resistance, humid environment adaptation, and fruit quality while contributing innovative strategies for crop improvement.   The end product of our research is new information on the genetics and molecular biology of disease resistance and fruit quality in tomato and varieties with improved disease resistance.

In tomato, adaptation to a humid growing environment requires resistance to multiple pathogens affecting fruit and foliage. Genetic variation exists for traits important to humid environment adaptation within cultivated varieties of tomato (e.g. Scott et al, 1997).  In general, germplasm developed in the humid environment of Ohio tends to have a higher level of resistance to biotic and abiotic stress relative to germplasm developed for the California market.  Little research is available concerning the genetic basis of this resistance that is often characterized as “field resistance” to distinguish it from the better studied major gene resistance. 

Significant variation for fruit quality related to color, color uniformity, and the correlated nutritional component of lycopene also exists within elite germplasm (Sacks and Francis, 2001).  A growing body of work suggests fruit quality will provide a powerful case study of important interactions between genotype and environment.  For example, at least three QTL within cultivated tomato interact to produce uniform red fruit (Kabelka, 2001).  The expression of color is also highly influenced by the environment.  Environmental influences on color and lycopene content include soil nutrients, temperature, and precipitation.  Thus in variance partitioning, genotype, location, and genotype x location interactions make highly significant contributions to the overall variation for fruit quality.