USDA Forest Service

Pacific Southwest Research Station
Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research Topics Forest Genetics

Major Gene Resistance
Dominant genes conditioning hypersensitive necrosis exist in at least three species
(Resistant top, susceptible bottom)
sugar pine
Pinus lambertiana
western white pine
Pinus monticola
southwestern white pine
Pinus strobiformis
Cross Sections of sugar pine needles: flourescent illumination
micrograph of pine needle section under ultra-violet illumination micrograph of susceptible pine needle under ultra-violet illumination micrograph of  resistant pine needle under ultra-violet illumination
Mesophyll tissue flouresces in red.
Susceptible Reaction
Rust mycelium (blue) establishes in mesophyll, then pentrates vasular cylinder
Hypersensitive Reaction
Needle tissues collapsed, disorganized; mycelium is moribund.
MGR in the field:
Sugar pine and western white pine families segregating for MGR
Parent-offspring relationships:
uninfected and infected sugar pine seed parents in heavily infected stands.
Last Modified: Jun 4, 2014 11:44:37 AM