Submitted to: American Phytopathology Society
Publication Type: Abstract Only
Publication Acceptance Date: 3/28/2006
Publication Date: 7/28/2006
Citation: Bonde, M.R., Nester, S.E., Berner, D.K., Frederick, R.D. 2006. Effects of temperature on initiation of infection in soybean by isolates of phakopsora pachyrhizi and p. meibomiae. American Phytopathology Society. 96:S14.
Technical Abstract: The effects of temperature on urediniospore germination and germ-tube growth were compared among six isolates of Phakopsora pachyrhizi, one each from Taiwan, Zimbabwe, Hawaii, and Brazil, and two from the U.S., and an isolate of P. meibomiae from Puerto Rico. In addition, the effects of temperature during a nighttime dew period on initiation of infection on soybean were compared among P. pachyrhizi isolates from Taiwan, Zimbabwe, and Brazil. All isolates behaved similarly, with optimum temperature ranges of 17 to 28C for germination, germ-tube growth, and infection. Temperatures for maximum germination varied between 20 to 22C, and germ-tube growth from 19 to 22C, depending on rust isolate and duration of the dew period. Differences between specific isolates in optimum temperature for germination were sometimes statistically significant, but minor. Differences in optimum temperature for germ-tube growth were not significant. This very close similarity in the effects of temperature were observed among all P. pachyrhizi isolates, in spite of the fact that they had been collected from different parts of the world over a 24-year period. No differences were observed among P. pachyrhizi isolates in aggressiveness or symptoms on susceptible soybean cultivars.