engleski

Environmental and genetical influences on sugar beet yields and root quality

For sugar beet growing in Croatia are in using covered seed of monogerm triploid hybrids. They are mainly of domestic origin (creations of Osijek Sugar Beet Breeding Institute), but they exist also those of abroad origin (for example: KWS from Einbeck and Strube from Sollingen, Germany ; Maribo from Wien, Austria ; Van der Have from Kapelle, The Netherlands). By previous investigations, we found considerable differences of sugar beet yields and their quality among the growing seasons and among hybrids. Nine sugar beet hybrids of different origin (Os Sana, Os Nada, Os Ana, KW Maja, KW Dunja, KW Perla, Kristal, Marathon and Sirius) were grown under field conditions on Osijek eutric cambisol during five growing seasons from 1993 to 1997. The field trials were conducted in five replications (experimental plot 13.5 m2). Population density ranged from 80 to 90 thousands plant/ha. Soil and crop management practices were usual for sugar beet growing under our environmental conditions. In general, sugar beet was sown at the first decade of April and it was harvested in middle October. In the tested 5-year period, mean sugar beet root yield was 59.3 t/ha. Sugar beet yields ranged among the growing seasons (environmental influences) from 52.1 t/ha to 68.6 t/ha and among hybrids (genetic influences) from 57.9 t/ha to 62.6 t/ha (five-year means). The growing season of 1994 was the most favorable for sugar beet growing and mean yield was about 20% higher (68.6 t/ha) in comparison with remaining four years of testing (56.9 t/ha). Three hybrids (Os Sana, KW Maja and Marathon) yielded above 60 t/ha (mean 6.18 t/ha), while KW Dunja had the lowest yield 56.7 t/ha). Mean sucrose concentration (digestion) was 14.19% with range of variations among the growing seasons from 12.92% (1994) to 15.39% (1997) and among hybrids from 13.50% (Marathon) to 14.65% (Os Ana). Loss of sugar in processing as affected by root K, Na and amino-N contents was 2.42%, with range of variations among years from 1.92% (1993) to 3.25% (1994) and among hybrids from 2.25% (Os Nada) to 2.54% (Marathon). Sugar yield was 6.91 t/ha with range of variations among years from 6.30 t/ha (1995) to 7.70 t/ha (1993) and among hybrids from 6.56 t/ha (Marathon) to 7.36 (Os Sana). Weather conditions are important factors of sugar beet yield and quality. For example, the highest yields in the growing season 1994 are in close connection with adequate rainfall quantity (456 mm in 7-months period from April to October), especially during two summer months (July and August: 103 mm). At the same time, the lowest root quality is mainly result of the higher temperatures in July (23.9 oC), August (22.6 oC) and September (19.8 oC) and rainfall excess in September (120 mm). Also, the highest sugar yield in the growing season 1993 could be in connection with rainfall quantity and their distribution (410 mm from April to October) as well as by more favorable temperature regime during summer months (July 20.3 oC, August 20.2 oC and September 16.4 oC).

sugar beet; hybrid; yield; quality

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