Assessing potential genetic gains from varietal planting stock in loblolly pine plantationsThis article is part of a larger document. View the larger document here.
Forest landowners have increasingly more options when it comes to loblolly pine (Pinus taeda L.) planting stock. The majority of plantations in recent decades have been established with seedlings produced from second-generation open-pollinated (second-Gen OP) seed. However, foresters have begun recognizing the increased gains obtainable from full-sib families produced using mass-controlled pollination (MCP) techniques. The next step in genetic improvement is varietal forestry. Forest biotechnology firms are producing loblolly pine varietal planting stock for deployment in the Southeastern United States. Continued testing of this material will determine individual genotypes best suited for specific sites or desired products. In 2007, a Loblolly Pine Genetic Level Study was installed in northern Mississippi to examine differences in growth among second-Gen OP seedlings, MCP seedlings, and loblolly pine varieties derived from somatic embryogenesis. Following two growing seasons, the average height of the MCP material was slightly but significantly taller than that of the varietal planting stock. The average height of the top five performing varieties was 18 percent taller than the varietal average, 14 percent taller than the average height of the second-Gen OP, and 6 percent taller than the MCP material.