Studies of root yield and quality of 38 sugar beet hybrids were carried out depending on digging time on two locations, in Topolje and Seleš. Two trials were done in Topolje, one with application of fungicides that preserved sugar beet leaves in vegetation period, another, with recorded heavy damage (no fungicide applied) on sugar beet leaves by C. beticola Sacc. disease. Trial with fungicides provided protection was conducted in Seleš.Sugar beet digging in the first period was done on 13thand 14thSeptember, and 34 days later in the second period (18thand 19thOctober). Weather conditions between the terms of digging were characterized by shortage in precipitation when compared to the multiyear average, which influenced autumn growth and technological maturation of sugar beet root.Prolonged vegetation period for 34 days in the second term of digging in the trial with leaves preserved (fungicide application) for two locations on the average resulted in root yield increase by 9.75 t/ha i.e. 11.34%, sugar content by 0.79% and pure sugar yield by 2.17 t/ha. Consequently, in the second half of September and the first half of October root yield was daily increased by 278 kg/ha, sugar content by 0.02 % and pure sugar yield by 63.8 kg/ha. The trial with leaves damaged (no fungicide application) had daily root growth of 217 kg/ha i.e. 7.39 t/ha in 34 days. However, sugar content was not increased, but lowered by 0.08%. In addition, the rate of soluble non-sugars (K, Na, AmN) was increased which made values of sugar in molasses higher giving rise to the decrease in sugar utility. In this trial with 34 days prolonged vegetation period, sugar yield was increased by 0.94 t/ha (8.47%), daily only 27.6 kg/ha. Considerable differences in yield were also determined between these hybrids. Therefore, recommendation, and intention for sugar beet digging as later as possible, can be justified only with health and preserved sugar beet leaves, selecting adequate hybrids.
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Faculty of Agriculture in Osijek (provided by DOAJ)