[Development of Pythium ultimum var. ultimum trow on different cultural media depending on temperature].

Pythium ultimum var. ultimum 175 was isolated for the first time from root system of rape. Influences of two kinds of temperature (10 and 25 degrees C) and 8 different cultural media on the strain growth and development was investigated. Using the growth-rate criterion the author has determined linear velocity of growth, which varied from 0.43 to 0.68 mm/h at 10 degrees C and from 0.78 to 1.11 mm/h at 25 degrees C. As to the velocity of growth the culture P. ultimum var. ultimum 175 is comparable to the well-known cultures of Neurospora crassa, and in some cases its growth velocity is higher. The best growth and formation of the oospores of P. ultimum var. ultimum 175 is marked on oats agar at 25 degrees C. The obtained results characterize the studied isolate as a high-parasite culture with respect to the spring rape.