Potravinarstvo ® Scientific Journal for Food Industry Volume 10 384 No. 1/2016 Potravinarstvo, vol. 10, 2016, no. 1, p. 384-392 doi:10.5219/626 Received: 11 April 2016. Accepted: 6 June 2016. Available online: 15 July 2016 at www.potravinarstvo.com © 2016 Potravinarstvo. All rights reserved. ISSN 1337-0960 (online) License: CC BY 3.0 SWEET POTATO (IPOMOEA BATATAS L.) GROWING IN CONDITIONS OF SOUTHERN SLOVAK REPUBLIC Miroslav Šlosár, Ivana Mezeyová, Alžbeta Hegedűsová, Marcel Golian ABSTRACT The sweet potato (Ipomoea batatas L.) belongs to very important crops from aspect of its world production. It is grown in large areas in Asia, on the contrary, sweet potato production in Europe presents minimal part of its total world rate. The sweet potato is less-known crop, grown only on small area in home gardens in Slovak Republic. Tubers of sweet potato are characterized by anti-diabetic, anti-oxidant and anti-proliferative properties due to the presence of valuable health- promoting components, such as carotenoids or vitamin C. The main objective of study was testing of sweet potato growing in conditions of southern Slovak Republic with focus on quantity and quality of its yield. The field trial was realised on land of the Slovak University of Agriculture in Nitra in 2015. Within trial, effect of cultivar and mulching on the selected quantitative (average tuber weight; yield per plant; yield in t.ha -1 ) and qualitative (total carotenoids; vitamin C) parameters were tested. One certified cultivar of sweet potato 'Beauregard' was used as a comparative cultivar. Other two cultivars were marked according to the market place at which were purchased and sequentially used for seedling preparation. Tubers of first un-known cultivar were purchased in the Serbian market (marked as 'Serbian'). Tubers of next sweet potato cultivar were purchased on the market in Zagreb (marked as 'Zagrebian'). Outplating of sweet potato seedlings were realised on the 19th May 2015. The sweet potato was grown by hillock system. Each cultivar was planted in two variants (rows): non- mulching (bare soil) and mulching by black non-woven textile. All variants were divided to three replications with 6 plants. Difference between rows was 1.20 m and seedlings were planted in distance of 0.30 m in row. The harvested tubers were classified in two size classes: >150 g (marketable yield) and <150 g (non-marketable yield). Total carotenoid content was determined spectrophotometrically. The vitamin C content was measured chromatographically (HPLC). The highest values of average tuber weight, yield per plant and total yield (t.ha -1 ) were found in cultivar 'Serbian'. Statistical analysis showed statistically significant difference in all yield quantitative parameters of cultivar 'Serbian' against cultivars 'Beauregard' and 'Zagrebian'. The highest content of total carotenoids was determined in cultivar 'Serbian' (99.52 mg.kg -1 fresh weight) with orange-creme flesh color, followed by cultivar 'Beauregard' (94.78 mg.kg -1 ) with orange flesh color and cultivar 'Zagrebian' (28.79 mg.kg -1 ) with yellow-creme flesh color. Differences among all cultivars were showed as statistically significant. The highest vitamin C content was detected in tubers of cultivar 'Serbian' (155.70 mg.kg -1 ), followed by cultivar 'Beauregard' (154.37 mg.kg -1 ) and cultivar 'Zagrebian' (146.33 mg.kg -1 ). Statistical analysis confirmed differences among cultivars as statistically non-significant. The mulching of sweet potato plants had statistically significant impact to all quantitative and qualitative characteristics of sweet potato. The application of black non-woven textile resulted in increase of average tuber weight, tuber yield and vitamin C content in sweet potato tubers. On the contrary, higher total carotenoid content was found in non-mulching variant compared to the variant with mulching. Keywords: Slovak Republic; sweet potato; yield; carotenoids; vitamin C INTRODUCTION The sweet potato (Ipomea batatas L.) belongs to the Convolvulaceae family and it is original from South America. Due to Christopher Columbus, it was imported to the Europe about century earlier than classical potatoes - Solanum tuberosum L. (Valíček et al., 2002). According to FAOSTAT (2016), total world production of sweet potato tubers was more than 100 milions tones in 2014. The main production area was Asia (75.3 %), followed by Africa (20.2 %), American continents (3.7 %) and Oceania (0.8 %). Sweet potato production in Europe presented the least part of its total world value (0.1 %) and the European production was only 56 113 tones in 2014. The main European producers of sweet potatoes was Spain and Italy. From world-wide aspect, China is the main producer of sweet potatoes within recent period. The production of this commodity was more than 70 milions tones in 2014. The other important producers was Nigeria, Tanzania, Ethiopia or Indonesia. Šlosár (2016) state that sweet potatoes are less-known crop, grown only on small area in home local gardens in Slovak republic. The sweet potato, known as batatas, is well known long- term species in a warm and hot climate zone and an annual plant (spring) in temperate zone. It produces moist and