Resin flow in clonal loblolly pine as a measure of southern pine beetle (Dendroctonus frontalis) resistance

The primary defense of loblolly pines, Pinus taeda, to southern pine beetle, Dendroctonus frontalis, attack is constitutive resin, which provides a physical barrier to beetle colonization. A study was conducted to determine resin production heritablity in clonal loblolly pines. Samples were taken in the spring and late summer of 2005 and 2006 in two plantations. Each site included nine complete random blocks containing improved and unimproved checks and 115 and 149 sampled clones, respectively. Two resin samples were collected from each tree after resin was allowed to flow for 22+/-2 hours. Total resin flow was found to be significantly higher in one family than the improved check. Resin production by clonal loblolly pines was found to have moderately high repeatability and low positive correlation with tree volume. Results indicate that clone selection that includes resin production as well as desirable growth characteristics can result in loblolly pines that display decreased susceptibility to the southern pine beetle.