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Resistance

Resistance to Dothistroma pini Within Geographic Seed Sources of Pinus ponderosa. Glenn W. Peterson, Plant pathologist, U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, Forestry Sciences Laboratory, University of Nebraska, Lincoln 68583; Phytopathology 74:956-960. Accepted for publication 9 March 1984. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1984. DOI: 10.1094/Phyto-74-956.

In plantings of Pinus ponderosa established in 1968 in Nebraska, Oklahoma, and Missouri, seedlings from a total of 78 geographic seed sources were tested for resistance to Dothistroma pini which causes needle blight. There was high resistance to D. pini in seedlings from six of the sources: four from New Mexico, one from Arizona, and one from Nebraska. Trees from most of these sources were above plantation averages in height after 10 yr of growth. Thus, there are a number of areas where seed can be collected for the production of seedlings that may be planted where D. pini is a threat.