Aggressiveness of Alternaria alternata (Fr.) Keiss for influence of sunflower hybrids and cultivation technologies

Abstract

Phytopathogenic aggressiveness is the ability of a fungus to reproduce in the tissues of host plants, which is manifested in different growth rates of mycelium, intensity of spore formation, viability of fungal spores, duration of development cycle and its resistance to extreme conditions. Varieties and hybrids of crops have a significant effect on changing the aggressiveness of phytopathogenic micromycetes. Therefore, the aim of the study was to determine the aggressiveness of the fungus Alternaria alternata (Fr.) Keiss under the influence of sunflower hybrids grown in different technologies. The influence of sunflower hybrids on the change of aggression was studied using the methods given in the methodological recommendations of M.O. Lemezi. The aggressiveness of A. alternata under the influence of sunflower hybrids grown by different technologies was analyzed. The following indicators were used for evaluation: viability of phytopathogenic micromycete spores, intensity of its spore formation and score of sunflower seedlings by the studied fungus. And also determined the degree of aggressiveness and pathogenicity of the fungus A. alternata. According to the results of the study, a high dependence of the aggressiveness of the studied micromycete on the biological properties of sunflower hybrids of different breeding origin was established. The Dushko hybrid, compared to the Oliver hybrid, both in traditional and organic cultivation technologies, can significantly reduce the aggressiveness of the phytopathogenic fungus A. alternata. This indicator should be used for ecological research of sunflower hybrids as a factor of biological pollution of the agrocenosis, that will allow to managing the stability of agroecosystems and obtain environmentally friendly and safe crop products.