Thesis--Auburn University, 2009. / Abstract. Includes bibliographic references (p.71-87).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1962. / Includes bibliographical references (p. 42-45).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1962. / Includes bibliographical references (p. 87-88).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1978. / Includes bibliographical references (p. 146-151).

Managed pine forests are central to the economic vitality of the southeastern US. Over the past fifty years, the productivity of managed pine forests of this region have increased significantly with the development of new silvicultural technologies and the use of improved tree genetic material. Of the pine species present in the southeastern US, loblolly pine has arguably been the most intensively studied and widely planted by forest managers. Efficient operational deployment of improved genetic materials requires an understanding of how possible site conditions and silvicultural treatment may interact to affect maximum yield. There are a wide range of site conditions in the south as the result of regional climate gradients, soil type and soil drainage patterns. On the western edge of loblolly pine’s natural extent, Texas has a drier climate than areas to the east, and in Louisiana, there are also poorly drained Ultisols that are found in areas with little relief and are prone to flooding. However, on the basis of 10-year forest inventory data of pure-family plots from three different sites and under two levels of cultural regime intensity, my study found that superior genotype, Lob 5 from South Carolina, still showed best performance in the Western Gulf area, and high intensive treatment could improve stand growth and resistance to wind damage significantly. Further, my study compared the stand production and dynamics between pure- and mixed-family plots. I found that Lob 5 and Lob 4 showed the growth traits of competitive ideotype, and low intensive treatment increased the deployment effect significantly for competitive ideotype. Finally, my study examined leaf area index (LAI) and foliar nitrogen concentration (foliar N). The result showed that fast growing genotype had lower LAI and foliar N than slow growing one. It indicated that fast growing genotype had high resource use efficiency and nutrient requirement. This research provided critical information to guide industrial forest management in the WG (Western Gulf) area. First, introduced superior genotype continued to show good performance in this area. Second, combination of good genotype and high intensive treatment would increase plantation production significantly. Third, identification of ideotype would increase the accuracy of growth potential estimation in progeny test.

Loblolly pine (Pinus taeda L.) is an ecologically and economically important southern pine, distributed across the southeastern United States. Its genetic improvement for breeding and deployment is a major goal of the Western Gulf Forest Tree Improvement Program (WGFTIP) hosted by the Texas A&M Forest Service. Rapid advances in genomics and molecular marker technology have created potential for application of Marker Assisted Selection (MAS) and Genomic Selection (GS) for accelerated breeding in forest trees. First-generation selection (FGS) and second- generation selection (SGS) breeding populations of loblolly pine from east Texas were studied to estimate the genetic diversity, population structure, linkage disequilibrium (LD), signatures of selection and association of breeding traits with genetic markers using a genome-wide panel of 4264 single nucleotide polymorphisms (SNPs). Under- standing the genetic basis of local adaptation is crucial to disentangle the dynamics of gene flow, drift and selection and to address climate change. Bayesian mixed linear models and logistic regression were used to associate SNP variation with geography, climate, aridity and growth season length and markers with strong correlations were investigated for biological functions. Relatively high levels of observed (Ho = 0.178–0.198) and expected (He = 0.180-0.198) heterozygosities were found in all populations. The amount of inbreeding was very low, and many populations exhibited a slight excess of heterozygotes. The population substructure was weak, but FST indicated more pronounced differentiation in the SGS populations. As expected for outcrossing natural populations, the genome-wide LD was low, but marker density was insufficient to deduce the decay rate. Numerous associations were found between various phenotypes and SNPs, but few remained significant after false positive correction. Signatures of diversifying and balancing selection were found in markers representing important biological functions. Strong correlations supported by Bayes factors were found between various environmental variables and several SNPs. Logistic regression found hundreds of significant marker-environment associations, but none remained significant after false-positive correction, which was likely too stringent and will require further investigation. Annotations of significant markers implicated them in crucial biological functions. These results present the first step in the application of MAS to the WGFTIP for loblolly pine genetic improvement and will contribute to the knowledgebase necessary for genomic selection technology. Results from environmental association study provide important information for designing breeding strategies to address climate change and for genetic conservation purposes.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 60-64). Also available via the Internet.

Thesis (M.S.)--Auburn University, 2004. / Abstract. Vita. Includes bibliographical references.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 177-190). Also available via the Internet.

Thesis (Ph.D.)--Mississippi State University. College of Agriculture and Life Sciences. / Title from title screen. Includes bibliographical references.