Sunflower is a plant of origin from North America, one of the four important cultures grown for oil, along with soy, rapeseed, and peanuts. The most common species is Helianthus annus L., which is cultivated all over the globe as an oil and ornamental plant. In Romania, it became the main oleaginous plant shortly, due to excellent conditions of culture. Climate change is occurring in Romania and is interacting with agroecological factors to increase biotic stress in sunflower. The uneven distribution of precipitation has increased the chances of infection with necrotrophic pathogens. The main objective of this paper was to study the dynamics of pathogens in the sunflower culture influenced by both the use of fertilizers and the genetic characteristics of the hybrids, correlated with the economic potential offered by pedo-climatic condition found in the Transylvania Plains area. Following the determinations made in the experimental field regarding the level of attack, we identified two pathogens (Diaporthe helianthi, respectively Plenodomus linquistii). We can say that the highest degree of attack was found in the case of Phomopsis stem canker, whit an average attack at 11.72 %. The second pathogen identified in the experimental field was noted, with a meager attack degree (below 2%). Of the six hybrids, the least susceptible to pathogen attack was the Adagio hybrid with 4.25% and the most sensitive Neoma hybrid with an attack degree of over 20%. Data analysis show that from hybrids sensitivity to the attack of pathogens point of view, they can be divided into three groups: Adagio and Klarika slightly sensitive, Gracia and Europe mean sensitive, Neoma and NHK 12MO10 with an above-average sensitivity. The main objective of this paper was to study the dynamics of pathogens in the sunflower culture influenced by both the use of fertilizers and the genetic characteristics of the hybrids, correlated with the economic potential offered by pedo-climatic condition found in the Transylvania Plains area.

sunflower, disease, pathogen, fertilization, Diaporthe helianthi, Plenodomus lindquistii

biology

Presentation: oral