On the Origin of Fusiform Rust Resistance in Loblolly Pine

Studies of geographic variation in loblolly pine (Pinus taeda L.) have shown that seed sources from the western (generally west of the Mississippi River) and the northeastern part of the natural distribution are relatively resistant to fusiform rust, and those from elsewhere are susceptible. The greatest incidence of infection, on the other hand, is in the center of the distribution, exactly where the frequency of resistant genotypes is low. One might expect that the frequency of resistant genotypes would be higher where the disease is more prevalent, due to natural selection. It has been proposed that (1) fusiform rust resistance in loblolly pine in the west originates from hybridization with shortleaf pine. It is well known that shortleaf is resistant to fusiform rust, and it is also known that natural hybrids between the two species exist, and they seem to be more common in the west. (2) In the northeastern loblolly, it has been proposed that hybridization with pond pine is the source of resistance. Once again, natural hybridization between loblolly and pond pine is known to exist in the northeast, but not much is known about the relative resistance of pond pine to fusiform rust. Allozyme data was used to refute hypothesis (1) and cortical monoterpene data was used to refute hypothesis (2). A hypothesis is proposed involving selection during the Pleistocene to explain the present pattern of resistance and the development of a gene-for-gene pathosystem.Papers and abstracts from the 27th Southern Forest Tree Improvement Conference held at Oklahoma State University in Stillwater, Oklahoma on June 24-27, 2003

Detecting the genetic basis of local adaptation in loblolly pine ( Pinus taeda

In the Southern United States, the widely distributed loblolly pine contributes greatly to lumber and pulp production, as well as providing many important ecosystem services. Climate change may affect the productivity and range of loblolly pine. Nevertheless, we have insufficient knowledge of the adaptive potential and the genetics underlying the adaptability of loblolly pine. To address this, we tested the association of 2.8 million whole exome-based single nucleotide polymorphisms (SNPs) with climate and geographic variables, including temperature, precipitation, latitude, longitude and elevation data. Using an integrative landscape genomics approach by combining multiple environmental association and outlier detection analyses, we identified 611 SNPs associated with 56 climate and geographic variables. Longitude, maximum temperature of the warm months and monthly precipitation associated with most SNPs, indicating their importance and complexity in shaping the genetic variation in loblolly pine. Functions of candidate genes related to terpenoid synthesis, pathogen defense, transcription factors and abiotic stress response. We provided evidence that environment-associated SNPs also composed the genetic structure of adaptive phenotypic traits including height, diameter, metabolite levels and expression of genes. Our study promotes understanding of the genetic basis of local adaptation in loblolly pine, and provides promising tools for selecting genotypes adapted to local environments in a changing climate

Modular process modeling for OPC

Modular OPC modeling, describing mask, optics, resist and etch processes separately is an approach to keep efforts for OPC manageable. By exchanging single modules of a modular OPC model, a fast response to process changes during process development is possible. At the same time efforts can be reduced, since only single modular process steps have to be re-characterized as input for OPC modeling as the process is adjusted and optimized. Commercially available OPC tools for full chip processing typically make use of semi-empirical models. The goal of our work is to investigate to what extent these OPC tools can be applied to modeling of single process steps as separate modules. For an advanced gate level process we analyze the modeling accuracy over different process conditions (focus and dose) when combining models for each process step - optics, resist and etch - for differing single processes to a model describing the total process

Proceedings of the eighteenth southern forest tree improvement conference, May 21-23, 1985, Long Beach, Mississippi /

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