THE ECONOMIC VALUE OF POTATOES GRADES IN THE CONDITIONS OF THE TYUMEN REGION
In increase of productivity and improvement of tubers quality the grade and quality of landing material play a crucial role, so a constant search of the grades which are well adapted for climatic conditions of the Tyumen region is necessary. Results of studying of grades of potatoes of domestic and foreign selection in the conditions of the Tyumen region are presented in article. The task is set-to allocate the grades combining the moderate duration of the vegetative period with resistance to diseases, productivity, quality of tubers, keeping quality during the winter period. It is established that the grade Northern in the years of researches had the vegetative period 7 days shorter than a standard grade ‘Zhukovsky’ early. Grades Ramos and Sante on precocity were up to the standard, and Sarma and Romantsa for 2 and 4 days, respectively, ripened later. The studied grades of potatoes had well developed sheet surface of 34.7-41.3 thousand m²/hectare that above a standard grade. The exception was made by a grade Northern, but it had high an efficiency of photosynthesis - 4 g/m³/ days that provided formation of high productivity. In both years of researches the studied grades, especially Ramos, exceeded a standard grade ‘Zhukovsky early’ on productivity for 16.3-29.7%, at productivity of the last of 30.2 t/hectare. In the years of researches steadily formed productivity of Sarm and Sante grades. The same grades had the high level of profitability of 72 and 69% respectively, at a standard grade - 45%. The content of solid at the studied grades made 19.1-22.7%, starch - 12.5-16.2%, at a standard grade ‘Zhukovsky early’ - 17.3% and 10.9% respectively. Grades Ramos and Ramantsa on both indicators conceded to the standard. The low content of sugar was had Northern and Sarma (0.2-0.3%), it is possible to use them for processing on chips and other production. The content of nitrates in tubers at all studied grades, including the standard, was lower than maximum concentration limit. Grades Northern, Sarma, in the studied parameters present to Sante practical interest for producers of the Tyumen region.