Cultural filtrate toxicity and an aggressivity of geographically remote isolates Phomopsis (Diaporthe) helianthi Munt.- Cvetk., Michal., Petr

«OIL CROPS» Scientific bulletin, VNIIMK, 2006, is 2 (135). The influence of two- and three-week old cultural filtrate of 11 Phomopsis isolates on sunflower seeds germination and root growth of five-day old seedlings are described. Isolates with strong and weak toxicity of a filtrate are differentiated. Studying of sunflower stems disease dynamic is conducted in field conditions after artificial inoculation by every isolate in leaf petiole plants of two self-pollinated lines. An estimation of Phomopsis isolates aggressivity was conducted on two criteria: percent of plants where the infection has passed to a stem and a length of spot affection on the stem. The calculated factors coefficients of correlation and determination have shown that there is an essential causal relationship between toxicity of a filtrate and the first criterion of isolates aggressivity.