engleski

Influences of environment and genotype on yield and nitrogen contents in sugar beet

In general, satisfied root yields and their low quality are main characteristics of sugar beet growing in Croatia and they are under environmental and genetic influences. High quantities of soluble N components are in close connection with low sugar beet quality. Fifteen sugar beet genotypes of different origin were grown on Djakovo mineral gleysols (pH in 1n KCl = about 7 ; humus contents = about 2.25%) during the growing seasons of 1994 and 1996 in five replications. Gross of each experimental plot was 15m2. According to postharvest soil test, the soils were low supplied with K, while N and P status were normal. Fertilization were as follows (kg/ha): 120 N + 130 P2O5 + 180 K2O ( the growing season 1994) and 135 N + 125 P2O5 + 165 K2O ( the growing season 1996). Leaf samples for chemical analysis were taken in the first decade of July. Leaf nitrogen (N) contents were determined by Kjeltek system, while root properties were determined immediately after harvest (October) by VENEMA equipment. Considerable differences of sugar beet yields and their quality were found among tested genotypes and between two growing seasons. Low root yields could be in connection with low soil K status. Negative correlation was found between sucrose and amino-N contents. However, low correlation was found between sucrose and leaf N concentrations. Also, under identical environmental conditions were found considerable differences of sugar yields, digestion and amino-N contents, while leaf N concentrations were similar. Considerable low sucrose contents in the first year of testing are mainly result less favourable weather conditions characterizing drought stress in August and relative high air-temperature and rainfall quantities in September. The similar results were found by analogical testing in Osijek and Donji Miholjac areas, with exception of root yields which were considerably higher .

sugar beet; nitrogen; genotyp

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