YIELD OF THE ABOVEGROUND PARTS AND TUBERS OF JERUSALEM ARTICHOKE (Helianthus tuberosus L.) DEPENDING ON PLANT DENSITY
In the years 2010-2012 the effect of plant density was studied on the yield of the aboveground parts and tubers of Polish cultivars of Jerusalem artichoke, Albik and Rubik. The experiment was carried out on a light soil of a good rye complex in a randomized block design. The experimental factors included: I) Jerusalem artichoke cultivars: Albik, Rubik, II) plant density: 2, 4, 6, 8 plants·m-2. Cvs. Albik and Rubik, on average over the three years of research, did not differ in the dry matter yield of the aboveground parts and tubers. In the year with a higher rainfall total during growing season, cv. Albik gave higher yields, while in the year with a dry spell from July to September, cv. Rubik yielded higher. With a density of 6 and 8 plants·m-2 the dry matter yield of the aboveground parts was significantly higher compared with a density of 2 plants·m-2. The lowest tuber yield was obtained at a density of 2 plants·m-2, a significantly higher one at a density of 4 plants·m-2. Increasing plant density from 4 to 6
or 8 plants·m-2 did not result in an increase in the tuber yield. Increasing density from 2 or 4 plants·m-2 to 6 or 8 plants·m-2 caused a decrease in the number and weight of tubers per plant as well as in the average weight of a single tuber.