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Basidiospore Discharge in Gymnosporangium. S. M. Pady, Division of Biology, Kansas State University, Manhattan, Kansas 66502; C. L. Kramer, Division of Biology, Kansas State University, Manhattan, Kansas 66502. Phytopathology 61:951-953. Accepted for publication 9 March 1971. DOI: 10.1094/Phyto-61-951.

Basidiospore discharge in Gymnosporangium juniperi-virginianae, G. globosum, and G. clavipes was studied under controlled conditions with a Kramer-Collins spore sampler. Telia were soaked in water and suspended over a cool-mist vaporizer in an ISCO E-1 growth chamber. Discharge began within a few hours and continued for 2-3 days. In G. juniperi-virginianae and G. globosum under alternating conditions of light and dark, discharge was periodic with peak maxima occurring in the dark whether soaking and initial period were in light or dark. Continuous dark resulted in a single peak after 6 hr; in continuous light, the pattern was similar but the peak was after 20 hr. In G. globosum, under alternating light-dark periods, discharge peaked in the first 12 hr irrespective of conditions; but on the 2nd and 3rd days, the pattern was similar to that in the other species.