Fritz, R. S. DEB-9615038 This project will study the consequences of plant hybridization on resistance to plant-feeding insects and a rust pathogen. The PIs will use a model system of two willow species (Salix sericea and S. eriocephala) that naturally hybridize in large parts of their range. Molecular markers will be used to establish the purity of parents used in crosses and for identifying naturally introgressed plants. The study will use comparisons of resistance among genetic classes of willows growing in the two parental environments, and will measure the effects of genetic class and environment on fitness of seedlings in the presence and absence of a rust pathogen. The study will also determine experimentally if introgression affects resistance of introgressed plants compared to pure parents. Hybrid plants are widely used for agricultural and forest tree breeding. These plants often have growth and yield characteristics that make them more productive for commercial use. In several cases, however, hybrid plants have been found to be highly susceptible to disease. Understanding the consequences of hybridization on resistance may be important to controlling insect damage and diseases in hybrid populations and could reveal environmental and genetic factors that will improve commercial success of hybrid plants in agriculture and forestry.
