CONTENT OF MINERAL ELEMENTS IN THE LEAVES OF 'WILLAMETTE' AND 'MEEKER' RASPBERRY CULTIVARS

The scientific experiment was conducted during the period of 2018-2019 in a collection plantation of the Research Institute of Mountain Stockbreeding and Agriculture in Troyan with two introduced raspberry cultivars, 'Willamette' and 'Meeker'. The field experiment is based at intra-row spacings between plants (0.50 m and 0.30 m) and inter-row spacings of 3.00 m. The content of mineral elements in the leaves was found during the phenophases, such as full blossoming and fruit harvesting. The results show that 'Willamette' had the highest nitrogen content in the leaf samples in the variant of 0.50 m (3.37%) in 2019 during the phenophase of full blossoming of plants. The phosphorus amount had the highest value in the variant of 0.50 m in 'Meeker' cultivar, as it was 0.27% in the phenophase of full blossoming and 0.28% in fruit harvesting phenophase in the first experimental year. Of the studied elements, the highest content of potassium was reported during the fruit harvesting phenophase in 2018 for 'Willamette' and 'Meeker' at shorter planting distances (0.70%).