#31-90 “Genetics of Oak Response to Drought and Herbivory”
Kevin Rice, Dept. of Agronomy & Range Science, UC Davis
This project’s goal was to examine patterns and processes of local adaptation in blue oak (Quercus douglasii), arising from concerns that this species’ widespread lack of regeneration. Genetic differences at the population level were seen at 2 of 3 field sites (Hopland REC and Sierra Foothill REC) but not at the San Joaquin Experimental Range. Regional local adaptation was noted at Sierra, while potential relative “mal-adaptation” was seen in the Hopland population. The population from the more mesic Hopland site had lower water-use efficiency than the population from the drier San Joaquin Range site, suggesting a significant genetic component. Plasticity in this trait on a regional scale was suggested, as seedlings from acorns collected at various locations when planted at Hopland had lower water-use efficiency (WUE) than the seedlings planted at San Joaquin. Data indicated a highly significant family component to variation in seedling WUE, suggesting genetic variation within as well as between populations. Seedling WUE may be very phenotypically plastic; in normal rainfall years, seedlings exhibited a range of WUE, while in a very wet year most seedlings exhibited low WUE.