IMPORTANCE OF SORT SELECTION AND FUNGICIDES APPLICATION IN CERCOSPORA BETICOLA SACC. SUGAR BEET LEAF SPOT PREVENTION AND QUALITY ROOT HIGH YIELD ACHIEVEMENT

Vrijednost sorata šećerne repe te njihova tolerantnost prema uzročniku pjegavosti lišća (Cercospora beticola Sacc.) istraživana je u uvjetima prirodne infekcije bez i uz primjenu fungicida, tijekom dvije godine (2004., 2005.), na dvije lokacije (Topolje, Seleš). Vrednovanje sorata šećerne repe izvršeno je preko pokazatelja prinosa i kvalitete korijena te prinosa čistog šećera, kao i vizualnom ocjenom oštećenja listova. U istraživanje je uključeno 26 sorata koje se koriste u širokoj proizvodnji ili se njihovo uvođenje očekuje. Istraživane sorte pokazale su nedovoljnu tolerantnost prema gljivi C. beticola Sacc. pa je primjenom fungicida u odnosu na netretirane pokuse povećan prosječni prinos korijena za 11,07 t/ha (14,8%), sadržaj šećera za 1,00% (rel. 7,1%) te prinos čistog šećera za 2,08 t/ha (23,0%). Na pokusima uz primjenu fungicida najveći prosječni prinos korijena postigla je sorta Libero (98,49 t/ha), najveću digestiju Iris 16,23%) i najveći prinos šećera sorta Merak (12,67 t/ha).Sugar beet hybrids value as well as their tolerance to the leaf spot agent (Cercospora beticola Sacc.) were researched in the natural infection conditions with and without fungicides application on two locations (Topolje, Seleš) in the two year period (2004, 2005). Evaluation has been done via root yield and quality, sugar yield as well as visual leaf damage estimation. The research comprised 26 sorts as either widely used in practice or to be introduced. The investigated sorts showed insufficient tolerance to C. beticola Sacc. Thus, fungicide application, compared to untreated trials, resulted in increased mean root yield by 11.07 t/ha (14.8%), sugar content by 1.00% (relative 7.1%) and sugar yield by 2.08 t/ha (23.0%). The trials with fungicide application were characterized by the highest mean root yield obtained with the Libero hybrid (98.49 t/ha), sugar concentration with the Iris sort (16.23%) and sugar yield with the Merak hybrid (12.67 t/ha)