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Baltunis B.S.,Forest Genetics | Russell J.H.,Cowichan Lake Research Station | Van Niejenhuis A.,Western Forest Products Inc. | Barker J.,1406 McNair Drive | El-Kassaby Y.A.,University of British Columbia
Silvae Genetica

Genetic analysis of height and form at age 12 years of 697 yellow cypress (Callitropsis nootkatensis [D. Don] Oerst.) clones tested across seven sites in coastal British Columbia (BC) were explored in populations: Population 1 - No Pedigree and Population 2 - Reconstructed Pedigree. Genetic variances were statistically significant but generally higher σC2 was observed for Population 2. Height and form were under low to moderate genetic control as indicated by clonal repeatability and estimates were relatively similar between populations. For example, average Ĥ2 in Population 2 was 0.31 for height (range: 0.18-0.45) and 0.22 for form (range: 0.06-0.32). While average Ĥ2 in Population 1 was 0.25 for height (range: 0.19-0.35) and 0.18 for form (range: 0.09-0.27). The reconstructed pedigree in Population 2 allowed partitioning the genetic variance (σC2) into component parts of additive (σC2 2), specific combining ability (σC2 s), and clone (σC 2 2); however, general lack of structure within the population resulted in variance components to be estimated with little precision for additive and specific combining ability. The majority of genetic variation was associated with clone for both traits. For example, σC2 accounted for 57.6% and 62.5% of the total genetic variance for height and form, respectively. Growth and form responses of clones across test environments were relatively stable and overall type-B genetic correlations were in excess of 0.8 for both traits implying clones selected for production populations should respond favorably across the seed planning zone for yellow cypress in coastal BC. Source

Gray L.K.,University of Alberta | Russell J.H.,Cowichan Lake Research Station | Yanchuk A.D.,Natural Resources Canada | Hawkins B.J.,University of Victoria
Agricultural and Forest Meteorology

Cedar leaf blight (. Didymascella thujina) is considered to be the most important disease of western redcedar in British Columbia. The disease is most prevalent in warm-moist coastal low-elevation environments causing mortality among seedlings and significant loss of incremental growth and branch death among mature trees. In this study we used a principle component regression model to spatially project the disease risk under observed climate (2003-2008) and multiple future climate scenarios for the 2020s, 2050s, and 2080s. We found that while the majority of future climate scenarios predicted coastal environments will continue to favor occurrence of the disease, intensity is predicted to decrease toward the 2080s. Projected reductions of available summer climate moisture (cumulative precipitation - potential evapotranspiration), corresponding to the time of ascospore discharge and germination, contribute significantly to this finding. Disease intensity is however, projected to increase under moderate temperature and precipitation increases for the 2020s. We therefore recommend current reforestation efforts deploy disease resistant western redcedar seedlots in high risk environments common to hypermaritime coastal regions such as Haida Gwaii and northern maritime, to avoid significant mortality and growth reduction. © 2013 Elsevier B.V. Source

Foster A.,Simon Fraser University | Mortimer L.,Simon Fraser University | Hall D.,University of British Columbia | Gries R.,Simon Fraser University | And 5 more authors.
USDA Forest Service - General Technical Report PNW-GTR

Reforestation with Thuja plicata is severely hampered by extensive ungulate browsing of seedlings. High foliar monoterpenoid content correlates with reduced browsing, providing a target for resistance breeding. The most abundant terpenoids in T. plicata foliage are the monoterpenes α- and β-thujone, both of which strongly deter ungulate browsing. Here we present work towards the development of alternative markers, morphological and genetic, that may improve accuracy and possibly also reduce the cost and time to predict monoterpene content in breeding populations. T. plicata foliage contains glands that presumably stores resin. We found that monoterpenes are almost entirely stored in resin glands, suggesting that the foliar amount of glands may correlate with foliar monoterpene content. We have found initial evidence in support of this hypothesis and are currently expanding the analysis. The genetic basis of monoterpenoid biosynthesis in T. plicata is unknown; however it is suspected that the monoterpene sabinene is the precursor of thujone biosynthesis. With the aim of identifying a T. plicata sabinene synthase, we sequenced a large number of expressed messenger RNA sequences from leaf foliage and compared the sequences to known monoterpene encoding genes. We identified several putative monoterpene synthase genes, one of which is expressed over 100-fold higher in foliage than the other genes. Expression of this gene is localized to the epithelium of foliar resin glands. In vitro enzyme assays showed that the corresponding protein converts geranyl pyrophosphate almost entirely into sabinene. In line with its expression in gland epithelium, the expression of this gene is very low in breeding lines lacking resin glands and high in breeding lines with large and many resin glands. In summary, we are well underway towards developing both morphological and genetic markers for foliar monoterpene content and indirectly also for ungulate browsing resistance. Source

Foster A.J.,Simon Fraser University | Foster A.J.,Laurentian Forestry Center | Hall D.E.,University of British Columbia | Mortimer L.,Simon Fraser University | And 6 more authors.
Plant Physiology

Thuja plicata (western redcedar) is a long-lived conifer species whose foliage is rarely affected by disease or insect pests, but can be severely damaged by ungulate browsing. Deterrence to browsing correlates with high foliar levels of terpenoids, in particular the monoterpenoid a-thujone. Here, we set out to identify genes whose products may be involved in the production of a-thujone and other terpenoids in this species. First, we generated a foliar transcriptome database from which to draw candidate genes. Second, we mapped the storage of thujones and other terpenoids to foliar glands. Third, we used global expression profiling to identify more than 600 genes that are expressed at high levels in foliage with glands, but can either not be detected or are expressed at low levels in a natural variant lacking foliar glands. Fourth, we used in situ RNA hybridization to map the expression of a putative monoterpene synthase to the epithelium of glands and used enzyme assays with recombinant protein of the same gene to show that it produces sabinene, the monoterpene precursor of α-thujone. Finally, we identified candidate genes with predicted enzymatic functions for the conversion of sabinene to α-thujone. Taken together, this approach generated both general resources and detailed functional characterization in the identification of genes of foliar terpenoid biosynthesis in T. plicata. © 2013 American Society of Plant Biologists. All Rights Reserved. Source

Russell J.H.,Cowichan Lake Research Station | Ferguson D.C.,Cowichan Lake Research Station
USDA Forest Service - General Technical Report PNW-GTR

This presentation reviews progress of the British Columbia Ministry of Forests and Range deer browse resistant breeding program. Tremendous progress has been made in a short period of time selecting for foliar monoterpenes. We are currently in the third generation of breeding and testing. In addition, selected phenotypes have been bulked up through controlled crossing and vegetative propagation for future operational deployment trials. Source

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