Agronomic performance of watermelon under direct sowing system and seedling transplanting

ABSTRACT Watermelon is traditionally grown under direct sowing system. However, due to high costs of good quality seeds of improved cultivars, seedling transplanting is a promising alternative for watermelon production. This study aimed at evaluating, during two production cycles, the performance of watermelon under direct sowing cultivation system and seedling transplanting. The field trials were carried out from May to September, 2015 and 2016, at Setor de Horticultura da Escola de Agronomia of Universidade Federal de Goiás. In 2015, the experimental design was randomized blocks (DBC) with four replicates in a 2x4 factorial scheme (two hybrids: Manchester and Talisman, and two planting methods: direct sowing and transplanting 15-, 20- and 25-day old seedlings). In 2016, the experimental design was DBC with six replicates. The treatments consisted of three direct sowing dates (0, 5 and 10 days) and three different seedling ages (15, 20 and 25 days). Number of leaves, plant height and dry mass of seedlings of different ages, vine length and virus incidence along the crop cycle were evaluated. Upon significant F-test (5%) for seedling age, regression analysis was performed, and when cultivar effect was significant, Tukey test (5%) was used. Planting methods (direct sowing X seedlings) were compared by orthogonal contrasts. In 2016, the beginning of flowering was evaluated, and in both trials, the average crop cycle for each treatment was determined. Fruit length and width, fruit mass, thickness of the white part of the rind, and soluble solids content were evaluated at harvesting. The 25-day old seedlings had higher number of leaves, as well as, higher dry mass, comparing with seedlings on the transplanting day. Yield and fruit quality were not influenced by treatments. No significant differences for virus disease incidence were detected, in both production cycles. Direct sowing reduced the crop cycle in both field trials, with no differences in production and quality of fruits. Considering the costs of establishing watermelon fields as relevant, the results suggest the importance of direct sowing as the most viable method for watermelon cultivation, due to the ease of the process, as well as, reduction in costs related to seedling production and transplanting operations.