THE EFFECT OF THE ENVIRONMENT AND STORAGE ON NITRATE CONTENT IN VARIOUS POTATO CULTIVARS FROM 2 LOCALITIES

Six potato cultivars (Svatava, Nela, Albina, Sante, Radka, Rema) from two localities (Trstena, Jakubovany) in Slovakia were tested for nitrate content and its decrease during 4 months of household storage. The quantities of accumulated nitrates were found to depend first of all on locality. The cooler mountain locality of Trstena situated at higher altitude with higher proportion of N and K containing fertilizers and lower proportion of P containing fertilizers had more than double the nitrate content in tubers in comparison with the warmer and lower situated locality of Jakubovany. When the nitrate contents of the same cultivar from different localities were compared, only for cultivar Sante were the differences in nitrate quantities insignificant. When the percentage of nitrates decreasing during storage was investigated, it was found that the losses of nitrates were dependent on the cultivar and the health status of the tubers. The potatoes from Trstena were not so healthy as those from Jakubovany. The strongest nitrate loss was observed at the end of the investigation in the cultivar Albina from Trstena (55.5%) and Sante from Jakubovany (41.5%). Compared were also the differences in the nitrate content between individual cultivars on the same locality at the beginning and at the end of storage.