Treesearch

Sugar pine (Pinus lambertiana) is a long-lived conifer species found in forest ecosystems from southern California to northern Oregon (USA). It is highly susceptible to white pine blister rust (WPBR), caused by the fungal pathogen Cronartium ribicola. Two long-term operational programs to develop populations of sugar pine with genetic resistance to WPBR, one in Oregon and one in California, have been ongoing for more than four decades. Most of the resistance work involves artificial inoculation of young seedlings. A small percentage of sugar pine parents have complete resistance (a...

The slow growth and long generation time of the fiveneedle pines have historically enabled these trees to persist on the landscape for centuries, but without sufficient regeneration opportunities these same traits hinder the species’ ability to adapt to novel stresses such as the exotic disease white pine blister rust (WPBR). Increasing the frequency of resistance to WPBR is the foundation for options to sustain five-needle pine species in the presence of the pathogen Cronartium ribicola. The objective of management intervention in the high elevation ecosystems is to promote pine population...

Western white pine (WWP, Pinus monticola) is a long-lived conifer with an extensive geographic range in western North America. It is of high interest in ecological studies and forest breeding because of its high susceptibility to the invasive disease white pine blister rust (WPBR, caused by the fungus Cronartium ribicola). However, P. monticola lacks genomic resources and is evolutionarily far away from plants with available draft genome sequences. Use of high-throughput RNA-sequencing (RNA-seq) technology is a costeffective strategy to generate substantial transcriptome data for global...

Melampsora larici-populina is causing leaf rust disease in poplar (Populus spp.) worldwide and poses serious problems to poplar breeders in France and in northern Europe. As with other rust fungi, its obligate biotroph status hinders laboratory investigations. Understanding the biology of rust fungi and deciphering the molecular mechanisms underlying biotrophy have long been a problem. Most of the knowledge gained was largely descriptive and limited to a few rust species; only recently has substantial progress been made in the characterization of avirulence determinants of the flax rust...

Improved resistance to comandra blister rust (causal agent: Cronartium comandrae) can improve lodgepole pine (Pinus contorta var. latifolia) survival and growth, but we lack information about resistance structure in this pathosystem. Incidence of comandra and other diseases was monitored annually in a 130-seedlot trial designed to both characterize the resistance structure in lodgepole pine and identify resistant families for inclusion in the tree improvement program in British Columbia, Canada. By 10 years of age, incidence of new comandra infection had largely stabilized on all three...

White pines exhibit both qualitative and quantitative resistance to white pine blister rust, which is caused by the fungal pathogen Cronartium ribicola (Sniezko et al. 2014). Species from several western U.S. States have a major gene at low frequencies that confers virtual immunity to the disease; and most also show heritable quantitative variation in infection frequency, as well as the ability to abort or heal infections that do occur (Kinloch et al. 2012). Here, we summarize extensive data from different tests, some previously published, showing the magnitude and pattern of variation in...

Five hundred whitebark pine (Pinus albicaulis) parent trees from 80 populations were collected from throughout the range of whitebark pine, and are to be deployed in long-term field tests to screen for resistance to blister rust. The objective is to identify individuals to provide resistant seed for restoration of the species now undergoing catastrophic population declines throughout most of British Columbia (BC), Canada. Two series of four test sites, each with half of the open-pollinated families, are to be deployed across the range in BC with the first series to be established in 2015...

The need for predictions of flow time-series persists at ungauged catchments, motivating the research goals of our study. By means of the Sacramento model, this paper explores the use of parameter transfer within homogeneous regions of similar climate and flow characteristics and makes comparisons with predictions from a priori parameters. We assessed the performance using the Nash-Sutcliffe (NS), bias, mean monthly hydrograph and flow duration curve (FDC). The study was conducted on a large dataset of 73 catchments within the eastern US. Two approaches to the parameter transferability...

Western white pine (WWP, Pinus monticola) is a wideranging, long-lived native conifer species in western North America. It is highly susceptible to the introduced fungal pathogen Cronartium ribicola, causative agent of white pine blister rust (WPBR). The impacts of the blister rust have reduced the incidence of WWP in natural ecosystems and have led to reluctance in using the species in both restoration and reforestation. Research and operational programs to develop genetic resistance to WPBR have been ongoing for more than five decades, with regional programs based in Oregon (USA), Idaho...

Naturally occurring genetic diversity is the material upon which much of the biodiversity we attribute to forested ecosystems is based. The structuring of genetic diversity within natural populations of forest trees results from the interplay of numerous evolutionary forces, such as genetic drift, migration, and natural selection. Landscape genomics is concerned with testing hypotheses about how these interacting evolutionary forces change over geographical space and time to shape naturally occurring patterns of this diversity. Here, I will use a landscape genomic approach to illustrate...