Treesearch

Western redcedar (Thuja plicata Donn ex D. Don), a member of the Cupressaceae, is an important commercial species in British Columbia (BC) and the Pacific Northwest (PNW), which is prized for its heartwood and its performance as a naturally durable outdoor building material. Although a genetic improvement program has been ongoing for only 15 years in BC, substantial progress has been made owing in part to its unique genetic and biological properties. These include early precious flowering and short generations (Russell and Ferguson 2008), the ability to self with minimal inbreeding...

Abiotic and biotic stressors exert selective pressures on plants, and over evolutionary time lead to the development of specialized adaptations and specific responses to stresses (Safranyik and Carroll 2006, Wallin and Raffa 2002). In this way, the environment in which plants evolve shapes their life cycles, range, growth, reproduction, and defenses. Insects and diseases are particularly potent plant stressors. Insect herbivores exert pressure on plants by feeding on plant parts and using them to reproduce by forming galls and cysts. Some insect species carry mutualistic pathogens on their...

The goals of our studies are to describe the natural variation in the concentration of constitutive heartwood extractives; estimate the genetic parameters related to heartwood characteristics; determine whether there is a genetic connection between constitutive and inducible production of stilbenes; and, together with technical experts, to develop fast and reliable techniques to quantify stilbenes from wood samples and determine whether there are rapid ways to utilize the existing variation in silviculture. We are also collaborating with molecular geneticists to find the markers for pine...

Laurel wilt (LW) is a devastating, emerging disease of native and non-native members of the Lauraceae family in the southeastern United States. Currently, the fungal pathogen (Raffaelea lauricola) and its vector (Xyleborus glabratus) are found in Alabama, Florida, Georgia, Mississippi, and North and South Carolina. The wilt is decimating native stands of redbay (Persea borbonia (L.) Spreng.), and causing significant damage to planted and native sassafras (Sassafras albidum (Nutt.) Nees) and avocado (Persea americana Mill.). Research has addressed significant knowledge gaps that exist for...

During the last decades, European poplar breeders learned the hard way that Melampsora larici-populina (commonly abbreviated as Mlp…) has an impressive adaptive potential (McDonald and Linde 2002). This fungal pathogen defeated all the deployed cultivars carrying qualitative (i.e., complete) resistances inherited from the American eastern black cottonwood Populus deltoides Bartram ex Marsh. in less time than needed to grow a poplar tree

Eastern filbert blight (EFB) is a devastating fungal disease of European hazelnut, Corylus avellana L., and is considered to be the primary reason hazelnuts have not been developed as a commercial crop in the eastern United States. The pathogen, Anisogramma anomala, is native to a wide area east of the Rocky Mountains, where it is harbored by the wild hazelnut C. americana Marshall. While C. americana is tolerant of the disease, EFB causes stem cankers, dieback, and death of C. avellana, the hazelnut of commerce. The absence of EFB, along with a mild climate, allowed for the development of...

Endophytic fungi are generally considered to be plant mutualists that protect the host plant from pathogens and herbivores. Defensive mutualism appears to hold true particularly for seed-transmitted, alkaloid producing, grass endophytes. However, we propose that the mutualistic nature of plant-endophyte interactions via enhanced plant resistance to pathogens and herbivores should be reconsidered when focusing on woody plants.We compared phenotypic and genetic frequency correlations for two endophytic fungal genera (Fusicladium and Melanconium) and birch rust (Melampsoridium betulinum) with...

The hemlock woolly adelgid (HWA), Adelges tsugae (Hemiptera: Adelgidae), is an invasive forest pest that threatens the existence of eastern hemlock (Tsuga canadensis (L.) Carr.) and Carolina hemlock (T. caroliniana Engelm.) in the eastern United States. It is a small, aphid like insect with piercing-sucking mouthparts that it uses to penetrate its host plant and feed off the xylem ray parenchyma cells (Young et al. 1995). The hemlock woolly adelgid is native to eastern Asia and northwestern North America where it feeds on, but does not kill, its host (Annand 1924, Havill et al. 2006). The...