Exploiting Genetic Variation of Fiber Components and Morphology in Juvenile Loblolly Pine.

In order to ensure the global competitiveness of the Pulp and Paper Industry in the Southeastern U.S., more wood with targeted characteristics have to be produced more efficiently on less land. The objective of the research project is to provide a molecular genetic basis for tree breeding of desirable traits in juvenile loblolly pine, using a multidisciplinary research approach. We developed micro analytical methods for determine the cellulose and lignin content, average fiber length, and coarseness of a single ring in a 12 mm increment core. These methods allow rapid determination of these traits in micro scale. Genetic variation and genotype by environment interaction (GxE) were studied in several juvenile wood traits of loblolly pine (Pinus taeda L.). Over 1000 wood samples of 12 mm increment cores were collected from 14 full-sib families generated by a 6-parent half-diallel mating design (11-year-old) in four progeny tests. Juvenile (ring 3) and transition (ring 8) for each increment core were analyzed for cellulose and lignin content, average fiber length, and coarseness. Transition wood had higher cellulose content, longer fiber and higher coarseness, but lower lignin than juvenile wood. General combining ability variance for the traits in juvenile wood explained 3 to 10% of the total variance, whereas the specific combining ability variance was negligible or zero. There were noticeable full-sib family rank changes between sites for all the traits. This was reflected in very high specific combining ability by site interaction variances, which explained from 5% (fiber length) to 37% (lignin) of the total variance. Weak individual-tree heritabilities were found for cellulose, lignin content and fiber length at the juvenile and transition wood, except for lignin at the transition wood (0.23). Coarseness had moderately high individual-tree heritabilities at both the juvenile (0.39) and transition wood (0.30). Favorable genetic correlations of volume and stem straightness were found with cellulose content, fiber length and coarseness, suggesting that selection on growth or stem straightness would results in favorable response in chemical wood traits. We have developed a series of methods for application of functional genomics to understanding the molecular basis of traits important to tree breeding for improved chemical and physical properties of wood. Two types of technologies were used, microarray analysis of gene expression, and profiling of soluble metabolites from wood forming tissues. We were able to correlate wood property phenotypes with expression of specific genes and with the abundance of specific metabolites using a new database and appropriate statistical tools. These results implicate a series of candidate genes for cellulose content, lignin content, hemicellulose content and specific extractible metabolites. Future work should integrate such studies in mapping populations and genetic maps to make more precise associations of traits with gene locations in order to increase the predictive power of molecular markers, and to distinguish between different candidate genes associated by linkage or by function. This study has found that loblolly pine families differed significantly for cellulose yield, fiber length, fiber coarseness, and less for lignin content. The implication for forest industry is that genetic testing and selection for these traits is possible and practical. With sufficient genetic variation, we could improve cellulose yield, fiber length, fiber coarseness, and reduce lignin content in Loblolly pine. With the continued progress in molecular research, some candidate genes may be used for selecting cellulose content, lignin content, hemicellulose content and specific extractible metabolites. This would accelerate current breeding and testing program significantly, and produce pine plantations with not only high productivity, but desirable wood properties as well

A critique of some modern applications of the Carnot heat engine concept: The dissipative heat engine cannot exist

In several recent studies, a heat engine operating on the basis of the Carnot cycle is considered, where the mechanical work performed by the engine is dissipated within the engine at the temperature of the warmer isotherm and the resulting heat is added to the engine together with an external heat input. This internal dissipation is supposed to increase the total heat input to the engine and elevate the amount of mechanical work produced by the engine per cycle. Here it is argued that such a dissipative heat engine violates the laws of thermodynamics. The existing physical models employing the dissipative heat engine concept, in particular the heat engine model of hurricane development, need to be revised. This journal is © 2010 The Royal Society

Search for major genes with progeny test data to accelerate the development of genetically superior loblolly pines. Quarterly report [July - September 1999]

This quarterly report describes the progress made on the 3 research tasks of the project. The 3 research tasks are: (1) Develop genetic models and analytical methods; (2) Molecular confirmation of major gene segregation; and (3) Develop strategies for marker-assisted breeding

Adaptive fuzzy modeling framework for characterization of subsurface contamination

The objectives of characterization of subsurface contamination are to provide information for the evaluation of: (1) the environmental effects of these contaminants; and (2) alternate remediation measures. However, the procedure is very complex. Complete characterization is very time consuming and costly if not impossible, In this paper, we propose an adaptive fuzzy modeling framework for the characterization of potentially contaminated sites when there is a lack of complete knowledge and detailed information.link_to_subscribed_fulltex

Major Gene Detection for Fusiform Rust Resistance using Bayesian Complex Segregation Analysis in Loblolly Pine

Presence of major genes affecting rust-resistance of loblolly pine was investigated in a progeny population that was generated with a half-diallel mating of six parents. A Bayesian complex segregation analysis was used to make inference about a mixed inheritance model that included polygenic effects and a single major gene effect. Marginalizations were achieved by means of Gibbs sampler. A parent block sampling by which genotypes of a parent and its offspring were sampled jointly was implemented to improve mixing. The mixed inheritance model was compared with a pure polygenic model based on Bayes factor. Results showed that the mixed inheritance model was a better model to explain the inheritance of rust-resistance than the pure polygenic model in the diallel population. A large major gene variance component estimate (> 50 % of total variance), indicated existence of major genes for rust resistance in this loblolly pine population studied. Based on estimations of parental genotypes, it appears that there may be two or more major genes affecting disease phenotypes in this diallel population

A Blocking Gibbs Sampling Method to Detect Major Genes with Phenotypic Data from A Diallel Mating

SUMMARY: Diallel mating is a frequently used design for estimating the additive and dominance genetic (polygenic) effects involved in quantitative traits observed in the half- and full-sib progenies generated in plant breeding programs. Gibbs sampling has been used for making statistical inferences for a mixed inheritance model (MIM) that includes both major genes and polygenes. However, using this approach, it has not been possible to incorporate the genetic properties of major genes with the additive and dominance polygenic effects in a diallel mating population. A parent block Gibbs sampling method was developed in this study to make statistical inferences about the major gene and polygenic effects on quantitative traits for progenies derived from a half-diallel mating design. Using simulated data sets with different major and polygenic effects, the proposed method accurately estimated the major and polygenic effects of quantitative traits, and possible genotypes of parents and progenies. The impact of specifying different prior distributions was examined and was found to have little effect on inference on the posterior distribution. This approach was applied to one experimental data of Loblolly pine (Pinus taeda L.) derived from a 6-parent half-diallel mating. The result suggested that there might be a recessive major gene affecting height growth in this diallel population