VIEW ARTICLE

Genetics

Genetic Variation of Epidemiological Fitness Traits Among Single-Aeciospore Cultures of Cronartium ribicola. G. I. McDonald, Principal plant pathologist, USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT 84401; D. S. Andrews, biological laboratory technician, USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT 84401. Phytopathology 72:1391-1396. Accepted for publication 3 November 1981. 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, 1982.. DOI: 10.1094/Phyto-72-1391.

Single aeciospores of Cronartium ribicola (cause of white pine blister rust) were isolated from single aecial blisters produced by artificially inoculating a wild population of Pinus monticola seedlings with a wild population of basidiospores. Aeciospores were isolated and cultured on detached leaves of a single Ribes hudsonianum var. petiolare clone. Cultures stratified by color of needle lesion on the infected pines showed no significant variation. But, stratification by individual blisters showed highly significant variation in four epidemiological fitness traits: culture size 30 days after inoculation, uredial sorus density 30 days after inoculation, percent of successful uredial subcultures per aeciospore line, and percent of uredial subcultures per aeciospore line producing teliospores by 35 days. Quantitative genetic analysis suggested strong genetic control in the wild rust pathogen population of all four traits. Results are discussed in relation to the analysis of quantitative genetic variation in C. ribicola.