Open Access
Breen, Peter C.
Area of Honors:
Bachelor of Science
Document Type:
Thesis Supervisors:
  • John Edward Carlson, Thesis Supervisor
  • Stephen B Hedges, Honors Advisor
  • Claude Walker Depamphilis, Faculty Reader
  • PCR
  • DNA fingerprinting
  • black cherry
Black cherry (Prunus serotina) is an important hardwood tree species in the United States of America because of its valuable timber; however it is a semi-invasive species in Europe. The Prunus species have been extensively studied with markers and linkage maps developed in many of the species. The main goal of our project is to identify QTLs related to response to ozone stress in black cherry. By identifying QTLs related to response to ozone stress, we can develop black cherry which are more resistant to ozone stress. This will help protect a valuable resource in the United States. To accomplish this, we needed to develop linkage maps based on full sibling populations of black cherry. PCR-based DNA fingerprinting was used to identify full siblings. QTLs can be located on the linkage maps. We worked with open-pollinated populations of black cherry in this study. This meant that the crosses were not controlled, and so we had to perform whole population screening by using SSR markers to look for the full siblings in the populations needed to build linkage maps. These seedlings were obtained from black cherry which were first used by Penn State faculty members John Skelly and Kim Steiner, who studied black cherry for response to ozone stress. In this study we used three families of black cherry: MO-21 (most tolerant to ozone), R-14 (most sensitive to ozone), and R-12 (intermediate tolerance to ozone). We extracted DNA from 600 samples from each seedling population of MO-21 and R-14. SSR markers developed from an initial EST black cherry library were identified and screened for polymorphism in the black cherry population. To date we have found 76 SSR markers to amplify and only two to be polymorphic. The screening is in process and as more markers will be found to be polymorphic they will be used for PCR to screen the families for full siblings. Linkage maps will be constructed from these data to identify QTLs related to ozone stress.