Stephen Alexander, Host-Pathogen Interactions In a Segregating Population of BC2F2 Hybrid Castanea Dentata and Other Chestnut Hybrids After Exposure To Hypovirus-Containing and Hypovirus-Free Strains of Cyphonectria parasitica
Faculty Chair: Dr. Hill Craddock
An Fz population of second backcross interspecific hybrid chestnut trees (BC2F2) and the progeny of the Chattanooga Chestnut Tree Project (CCTP) breeding program were exposed to three isogenic strains of Cryphonectria parasitica. Strain Epl55 (virus-free) was used to screen the 4 - 7 year old chestnut trees for resistance to chestnut blight disease. Two virus-containing, hypovirulent strains, Epl55 (CHVl-Euro7) and Epl55 (CHVl-Ep713), were used to investigate interactions of host disease resistance and expression of hypo virulence. The BC2F2 population varied from highly susceptible to highly resistant, as measured by Epl55 (virus-free) canker length at 95 days. Disease resistance in the CCTP population varied from highly susceptible to intermediately resistant. Epl55 (CHVl-Ep713) cankers were significantly smaller than cankers caused by Epl55 (CHVl-Euro7) and Epl55 (virus-free). Investigation of the interactions of host disease resistance and expression of hypovirulence is currently in progress at the CCTP breeding orchard.