Vertical Pillar Type and Fruit Setting Method for Vertical Cultivation of Small-Sized Watermelon

Korean consumers prefer various types of watermelons such as the seedless or colored ones, but, nowadays, large-sized watermelons are produced more than the small-sized ones. In order to satisfy all consumer needs, this research developed a vertical cultivation method that enables mass-production of high-quality small-sized watermelons. The watermelon varieties used in this study are "Lycofresh No. 2" (diploid) and "Black Boy" (triploid), and the vertical pillar types were evaluated after dividing them into different types, such as I-type, boolean AND-Type, semi-runner type and runner type. As for the planting distances, plant growth yields were compared among the following categories: 20 cm, 30 cm, and 40 cm. The fruit setting method was performed for female flowers No. 2 (12 - 16), No. 3 (19 - 23), and No. 4 (26 - 30) node positions. As a result, small-sized watermelon vertical cultivation technology was established as follows. Using the I-type, the cultivations were planted at a distance of 20 cm. A stem was cultivated using two stalks and an induction net. The fruit setting position was the third female flower, and the shoot apex was removed through a pruning method at the end of the stem, 2 days before the female flowers bloomed. The vertical cultivation method developed in this study makes it possible to cultivate 3,000 plants/10 acres in a 6 m single span-type greenhouse. Thus, the marketable yield of 'Lycofresh No.2' increased 2.6 times and that of 'BlackBoy' increased 2.9 times, compared with the conventional cultivation type (runner type), in a cultivation area of 10 acres. Growing small-sized watermelons with I-type vertical cultivation increases the yield and, consequently, the farmer's income. In addition, the change of posture from squatting to standing also improves the conditions of labor to them. Altogether, our results indicate that our procedure represents a more efficient and convenient cultivation method.