Genetic Variation and Genotype by Environment Interaction of Juvenile Wood Properties in Loblolly Pine (Pinus taeda L.), 2004 Paper Summit, Spring Technical & International Environmental Conference, (including Papermakers; Process Control, Electrical & In

Genetic variation and genotype by environment interaction (GxE) were studied in several juvenile wood traits of loblolly pine (Pinus taeda L.). Wood samples of 12 mm increment cores were collected from 11-year-old trees in two progeny tests. Earlywood and latewood of ring 3 (juvenile wood) and ring 8 (transition wood) for each increment core were analyzed for α-cellulose content (ACY), average fiber length (FLW), coarseness (COA) and lignin content (LIG). Transition wood (ring 8) had higher ACY, FLW, COA but lower LIG than juvenile wood (ring 3). Families differed significantly for all the chemical and morphological wood properties on both sites. Genetic variation due to general combining ability and specific combining ability was greater in transition wood than juvenile wood. Loblolly pine full-sib families differed significantly for all traits except for LIG on both sites. There were noticeable family rank changes between two sites for these traits, and there was a large site by specific combining ability interaction effect, which was due to non-additive genetic effect by environment interaction. While weak individual-tree and family heritabilities were found for ACY, FLW, and COA for the juvenile wood, the heritability estimates for the transition wood were moderately high. Favorable genetic correlations of volume and stem straightness were found with ACY, FLW, COA.