Genetic Variation and Parameter Estimation of Juvenile Wood Properties in a Diallel Loblolly Pine (Pinus taeda L.) Population.

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dc.contributor.advisor Bailian Li, Committee Chair en_US
dc.contributor.advisor Gary Hodge, Committee Member en_US
dc.contributor.advisor Barry Goldfarb, Committee Member en_US
dc.contributor.advisor John Kadla, Committee Member en_US Sykes, Robert Wayne en_US 2010-04-02T18:14:52Z 2010-04-02T18:14:52Z 2004-05-17 en_US
dc.identifier.other etd-05102004-141036 en_US
dc.description.abstract Genetic tree improvement has made substantial gains in productivity, stem straightness, and rust resistance for loblolly pine (Pinus taeda L.) in the southern U.S. Improved growth has reduced rotation ages to 20 to 25 years for intensively managed plantations, resulting in a higher percentage of juvenile wood from plantations. Juvenile wood, with low density, shorter tracheid length and higher lignin content, has been shown to reduce yields and increase pulping costs. However, wood properties of juvenile wood can be improved if there is sufficient genetic variation within the breeding population. This study examined the genetic variation and genotype by environment interaction for several important wood properties in loblolly pine, and investigated the rapid assessment of these wood traits by Near Infrared spectroscopy. Increment cores were collected from fourteen 11-year-old full-sib families from one progeny test. Earlywood and latewood of ring 3 (juvenile wood) and ring 8 (transition wood) for each increment core was analyzed for α-cellulose content (ACY), average fiber length (FLW), coarseness (COA) and lignin content (LIG). Transition wood had significantly higher ACY, FLW and COA and lower LIG than juvenile wood. Latewood of both rings had higher ACY, FLW and COA than earlywood. Loblolly pine families differed significantly for ACY, FLW and COA, but not for LIG. In general, additive genetic effects explained greater percentages of family variation than dominance genetic effects in these traits. For all traits, genetic variation increased from juvenile to transition wood. While weak individual heritabilities were found for ACY, FLW and COA for juvenile wood, individual and family heritability estimates for transition wood were moderate. Genetic variation and genotype by environment (GxE) interaction were examined for these juvenile wood properties by combining the data from an additional test site. 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. Noticeable family rank changes were observed between two sites for these traits, which were largely due to a significant site by specific combining ability interaction. The family heritability estimates from the combined analysis showed that ACY, FLW, and COA in transition wood were under moderate degrees of genetic control. Favorable genetic correlations with stem straightness were found for ACY and FLW. Near infrared (NIR) spectroscopy was examined for the rapid estimation of ACY, FLW, and COA. Transmittance measurements of NIR spectra from thin wood wafers cut from increment cores were used to develop calibration models for ACY, FLW, LIG, and COA measured in the laboratory. Calibrations based on one site were generally reliable with coefficients of determination (R²) ranging from 0.55 to 0.86 for FLW and ACY, respectively. Predicting ring 8 spectra using ring 3 calibration equations may be possible for ACY and COA with R2 values around 0.60. Predicting the wood properties from one site to the other may be possible for ACY and COA but not for FLW. Significant genetic variation among and within families and moderate heritabilities from this study suggest that it may be possible to improve wood properties of juvenile wood through tree improvement programs in loblolly pine. Positive genetic correlations of wood density with ACY, FLW and COA indicate that genetic improvement of wood density may improve these important wood and traits. While NIR spectroscopy showed feasibility as a rapid method to predict wood properties for many trees, sampling techniques need to be refined before using NIR to assess wood properties for breeding programs. en_US
dc.rights I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. en_US
dc.subject transition wood en_US
dc.subject juvenile wood en_US
dc.subject wood quality en_US
dc.subject prediction of wood properties en_US
dc.subject Transmittance NIR spectroscopy en_US
dc.title Genetic Variation and Parameter Estimation of Juvenile Wood Properties in a Diallel Loblolly Pine (Pinus taeda L.) Population. en_US MS en_US thesis en_US Forestry en_US

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