POTATO MINITUBER PRODUCTION AT DIFFERENT PLANT DENSITIES USING AN AEROPONIC SYSTEM

Minitubers with a size of more than 20 mm produced directly from in vitro plantlets using an aeroponic system could be considered as high quality seed potatoes. The aim of the present work was to investigate the effect of plant density (25, 35 and 50 plants per m²) on minituber production in aeroponics. The aeroponic cultivation system consisted of eighteen sections covered by Styrodur^® sheets. Nutrient solution was sprayed by fog nozzles every 5 min for 20 s. Potato plantlets (Solanum tuberosum L. ‘Marfona’) obtained by in vitro cultivation were acclimatised in the greenhouse and then planted in small rockwool cubes which were fixed in holes in the Styrodur^® sheets. Morphological parameters such as leaf number and stem length were recorded. Minitubers larger than 20 mm were removed weekly in eight harvests in total. At the last harvest, all minitubers larger than 5 mm were evaluated. Number of minitubers and total yield were recorded at every harvest. The plants exhibited a vegetative cycle of about 4 months. Minituber harvesting started two months after transplanting into the aeroponics and lasted for two months. The highest number of minitubers per plant was obtained in case of 25 plants per m² with 40.82 in total, regarding tubers larger than 20 mm with 32.2. The yield per m², however, was not affected by the plant density. In the case of 25 plants per m², an average of 805 minitubers >20 mm or 11.1 kg could be harvested per m² compared with 11.2 and 10.4 kg per m² for 35 and 50 plants per m², respectively.