USABLE AND NON-USABLE BIOMASS OF POTATOES GROWN UNDER TWO CROP PRODUCTION SYSTEMS AND TWO DIFFERENT ENVIRONMENTAL CONDITIONS.

A field study was conducted in years 2011-2013 in two different places in Poland. Four potato cultivars (Flaming - very early, Viviana - very early, Vineta - early, Gustaw - mid early) were grown under organic and integrated systems. During the full development stage, i.e. end of June (for the early varieties) and 2 weeks later (for later ones) total above-ground biomass was assessed. The tuber yield and share of tuber in total plant biomass was calculated during the harvest. It was stated that the highest influence on assimilates distribution to usable and non-usable part of plant had the site of growing and the cultivar. The farming system and the weather conditions during growing season did not significantly influence the share of tuber in total plant biomass. There was significant interaction between the farming system and the site of growing regard to total biomass and tuber yield. Under organic system on lighter soil the total biomass and the yield was slightly lower than on heavier soil, but under integrated system the relation was diverse. Relatively small diversity of cultivars regarding the share of tubers in the total biomass was noticed. [ABSTRACT FROM AUTHOR]