Occurence of Fusarium head blight on some wheat varieties in different plant population and nitrogen fertilisation during 2011 in Serbia

Wheat is one of the most important crops in Serbia. The average area under wheat in the Republic of Serbia in the period from 2000 to 2011 year amounted 579,289 ha, with an average yield of 3.48 t/ha. One of the most important diseases on wheat is Fusarium head blight which can cause a number of fungal species from Fusarium genus. Within species Fusarium graminearum, Group 2 is the most important. The consequences of infection of wheat ears by fungi from the genus Fusarium are different, but the most common are: reduced yield, physiological and physico-chemical changes of grain and grain mycotoxin contamination. The aim of the study was to test occurence of natural infection by Fusarium head blight of eight wheat varietes (Arabeska, NS 40S, Zvezdana, Arija, Gora, Gordana, Simonida, Etida), one spelt variety (Nirvana) and one triticale variety (Odisej). The occurence of Fusarium head blight was tested depending on applied amounts (0 kg/ha, 50 kg/ha, 100 kg/ha, 150 kg/ha) of nitrogen fertilizer ammonium nitrate (AN 33-35%N) in the form of spring nitrogen and on sowing density (300 grains/m², 500 grains/m², 700 grains/m², 900 grains/m²). Evaluation of intensity of Fusarium ears occurence was conducted in phenophase of milk stage. Agricultural parameters were monitored at Rimski Šančevi (10 kilometres from Novi Sad) locality during 2011. In May and June 2011 variable and warm weather conditions with less rainfall than average were registered. Weather conditions in May and June 2011 were not favorable for the development of fungi from the genus Fusarium and tested cultivars had low average number of infected ears. The highest average number of infected ears had NS 40S (15.3) and the lowest variety Gordana (2.0). On spelt and triticale variety, there was no significant occurence of the disease caused by fungi from the Fusarium genus. Quantity of applied nitrogen fertilizer as a topdressing wheat showed different effects on development of Fusarium head blight. It was found that the average number of infected ears is not in positive correlation with the applied nitrogen fertilizer, except in the variety Etida. Regarding sowing density effects on Fusarium ear infections, it was registered that NS 40S had the highest number of infected ears compared to other tested varieties regardless sowing density