Effect on Production and Quality of Intensifying Triploid Watermelon Crops Using ‘Temporary Trellises’ and CPPU for Fruit Development
In Spain, the adoption of the triploide ‘Queen of Hearts’ (Citrullus lanatus Thunb.) watermelon cultivar has brought important changes in the production of seedless watermelon thanks to its magnificent acceptance by the market. The experiments on triploid watermelon presented here examined innovative production techniques that would guarantee the productivity and quality of this cultivar in plastic greenhouses and improve cost-effectiveness, serving growers. Crop intensification was tested under a “temporary trellis” management system, increasing plant density from 2500 plants/ha in the traditional or creeping crop system to 10,000 plants/ha. The “temporary trellis” system was combined with fruit set through the localized application of a 150- to 200-mg·L−1 solution of 1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU). The increase of grafted watermelon plant density to 1 plant/m2 gave rise to an increase in early harvest measured as the number of fruits per surface area compared with the traditional system with a density of 0.25 plant/m2. In addition, a process of temporary trellising facilitates choosing female flowers for applying CPPU. The °Brix and pulp firmness quality parameters did not show significant differences between “temporary trellised” and creeping crops.