EFFECT OF SEED ORIGIN, FERTILIZATION AND PRUNING ON GROWTH, YIELD AND FRUIT SUGAR CONTENT OF GOLDENBERRY (PHYSALIS PERUVIANA L.)

Goldenberries (Physalis peruviana L.) originated from Andean regions are grown for their delicious and health promoting fruit. The cultivation is possible in temperate climates with respect to restrictions as frost intolerance and perennial growth character. To improve goldenberry cultivation concerning summer greenhouse conditions in Germany an experiment with goldenberry plants grown under sheltered conditions (foliar greenhouse, day/night 18/18°C, aeration 27°C) in grow-bags with fertigation was carried and implemented within six months (28 May until 22 October 2010). Two different seed origins and two nitrogen (N) fertilizer treatments were tested. To figure out the impact of pruning, half of the plants were pruned, in the way of cutting off two from the originally four first primary apical side shoots. Dry matter (DM), shoot elongation, and nitrogen concentration of vegetative plant parts were determined. Measurements of fresh and dry matter, nitrogen concentration, and total sugar content as well as saccharose, glucose, and fructose concentration in DM of reproductive plant parts (fruit) were made. N fertilizer treatment resulted in significant different DM of leaf, shoot, and root samples. Results of plant nitrogen concentrations in leaf samples showed a significantly higher N concentration if supplied with higher N fertilization. Yield and fruit quality parameters such as sugar concentration did not alter because of N level. Mean yield was 6.8 t/ha. Enzymatic optically analyzed concentration of saccharose was 25.9%, of glucose 12.8%, and of fructose 12.3% in DM. Pruning of first primary apical side shoots had a significant impact on total plant biomass and to some extent on fruit yield. In conclusion, for temperate climate regions cultivation of goldenberries is worthwhile with rather low fertilization in a grow bag system and under sheltered conditions.