A Study on Single-Truss Tomato Production by Hydroponics

Effects of Plant Density and Number of Leaf above the Truss on Plant Growth and Fruit Yield

Abstract

Effects of the plant density and the number of leaf above the truss on plant growth and fruit yield of single-truss tomato plants grown in the greenhouse by hydroponics were studied. At the range of plant density from 300 to 3, 000 plants/a, yield per unit area increased with increasing plant density. Fruits weight per plant increased at plant density below 1, 500 plants/a. In ‘Multi-First’, the number of fruits and fruit weight per plant more increased with decreasing plant density than those in ‘Momotaro’. As plant density increased, the mean weight per fruit decreased, puffy fruits increased and the percentage of marketable fruit decreased in both varieties. If the target is to harvest fruit of average weight from 150 to 200g, this target might be attained at plant density from 700 to 1, 200 plants/a in ‘Momotaro’, from 1, 000 to 1, 700 plants/a in ‘Multi-First’. For the reason described above and in consideration of the cost of seedlings and the working efficiency, the optimum plant density should be 1, 200 plants/a for the cropping type of winter sowing/spring harvesting in ‘Momotaro’, 1, 000 plants/a for the other cropping type in ‘Momotaro’ and in ‘Multi-First’. For the cropping type of autumn sowing/winter harvesting and spring sowing/summer harvesting, the yield was more than 700kg/a in ‘Momotaro’, 1, 000kg/a in ‘Multi-First’ at the plant density 1, 000 plants/a. For the cropping type of winter sowing/spring harvesting and summer sowing-autumn harvesting, the yield was less than those of the former cropping type. In ‘Momotaro’, for the cropping type of summer sowing that tomato tend to grow over or low solar radiation season, puffy fruit increased. To decrease puffy fruits, the number of leaf above the truss should be 1. For the other cropping type in ‘Momotaro’ and in ‘Multi-First’, as the percentage of marketable fruit was high, the number of leaf above the truss should be 3.