Due to the increasing production area and public consumption of the tropical crop sweet potato, it is important to constantly perform the biological and agrotechnical elements of production based on established experimental findings. We examined a strict field experiment on sweet potato with replications on calcareous chernozem soil in the Demonstration Garden of the University of Debrecen, Faculty of Agricultural and Food Sciences and Environmental Management, Institute of Crop Sciences. The experiment involved three varieties (Ásotthalmi 12, Norangel, Emmur), two planting methods (flat and ridge planting) and two row spacings (0.75 m and 1.0 m). Altogether, the extremely warm weather, the accessible water stock of the soil which filled up during the winter and irrigation (152 mm irrigation water) were favourable for tuber formation in sweet potato; therefore, outstanding marketable tuber yield was harvested in 2018 (33.3–62.3 t ha-1). Concerning all three involved varieties, higher yields were obtained in flat planting than ridge planting, but the observed yield differences showed variety-specific characteristics. In the case of the 1 m row spacing, the biggest differences were measured concerning the variety Emmur (6812 kg ha-1), while in the case of the 0.75 m row spacing, the biggest difference was shown by the variety Ásotthalmi 12 (10 325 kg ha-1) in favour of flat planting. Both in flat planting and ridge planting, all varieties produced higher yields in the case of 0.75 m row spacing in comparison with 1 m row spacing. In 2018, outstanding yield was obtained in the case of Emmur (43.1–62.3 t ha-1), but the yield level of the other two varieties was also very favourable (Ásotthalmi 12 33.3–47.3 t ha-1, Norangel 37.8–43.3 t ha-1 marketable tuber yield). The proportion of non-marketable tubers was the relatively highest in the case of Emmur (9.69–12.96%), while the other two varieties showed lower proportions (Ásotthalmi 12 8.35–10.90%, Norangel 8.77–11.08%). The proportion of non-marketable tubers was increased by ridge planting in comparison with flat planting.

Keywords: sweet potato, variety, planting method, row spacing, tuber yield