The productivity of biological forms of sugar beet as affected by growing season length

Abstract

Purpose. To find out productivity of biological forms of sugar beet as affected by the length of growing season.Methods. Field, visual, weight measuring, mathematical and statistical.Results. The plant density before harvesting of both biological forms of sugar beet (thousand per hectare) was almost the same: in diploid forms it varied from 105.9 to 106.9 and in triploid ones from 105.6 to 107.0, with LSD05 biological form of 0.56. Increase in the duration of growing season provided a significant increase in root yield. The highest root yield of both biological forms was obtained at the duration of the vegetation of 201 days, that is, at the latest harvesting date (November 10); root yield in diploid and triploid biological forms was 59.2 and 59.9 t/ha, respectively, which was by 6.3 and 6.8 t/ha higher than for the duration of the growing season of 161 days, at early root harvesting (September 30). Increase in the yield of domestic hybrids during October was more intense than that of foreign hybrids. Sugar content in the roots of diploid forms at the duration of vegetation of 161 days (harvesting on September 30) amounted to 15.1%, while at the duration of vegetation of 191 days (harvesting on October 30) it was 15.3 % and for the duration of vegetation of 201 days (harvesting on November 10) 15.6% in triploid forms 14.9%, 15.2% and 15.5%, respectively (LSD05 harvesting time = 0.15%). Sugar yield was affected not only by the biological forms of sugar beet, but also by the soil and climatic conditions. A similar tendency was observed as affected by a hybrid genotype.Conclusions. It was established that the increase in the duration of sugar beet vegetation provided significant increase in root yield and sugar yield in all the biologic forms. 191 days vegetation (30 days increase) and the second harvesting date provided an increase in root yield of diploid and tripod hybrids by 5.0 t/ha, comparing with the 161 days vegetation period. Increase in root and sugar content of both biological forms ensured an increase in sugar yield of 0.9 and 1.0 t/ha, respectively. The maintenance of the vegetation till November 10 (201 days) also had a significant effect on the yield of both diploid and triploid sugar beet forms, as compared to the second one. The increase in the yield of diploid forms was 1.3 t/ha and triploid 1.7 t/ha. However, postponing harvesting for such later period under the conditions of low moisture in the Right-Bank Forest-Steppe of Ukraine is risky. Therefore, 30–40 days prolongation of sugar beet vegetation is one of the main reserves for increasing rood yield, sugar content and yield.