Effect of leaf-area management on tomato plant growth in greenhouses

Photosynthesis in plants depends on various vegetative growth factors, such as leaf age, leaf area, and leaf number. Leaf area is related to canopy photosynthesis and production of crops. However, there are few studies that quantify the relationship between leaf area and crop growth according to various climatic conditions for tomato crops. Therefore, this study was conducted to quantify the relationship between leaf area and two cultivars of tomato plants in a greenhouse in the northeast Asian climate. In the experiment, tomato seedlings of 'Super334' and 'Poongyoung' were used. We ran the experiment from May 28 to September 16, 2019, with various leaf-area index (LAI) treatments. The greenhouse environments were managed to maintain a relative humidity of 38-90% and temperature of 15-35 degrees C. Irrigation was controlled based on accumulated radiation. We compared the tomato growth according to five leaf-area treatments: non-defoliation (control), LAI (2.5), LAI (3.0), LAI (3.5), and LAI (4.0). In terms of the vegetative growth of tomatoes, the smaller the LAI, the greater the plant height of the crops. In terms of reproductive growth, the number of flowers did not show significant differences between the control and the LAI treatments, but the number of fruits in the 'Poongyoung' cultivar seemed to increase with the higher LAI treatment. In terms of fruit quality, although fruit weight, sugar content, and acidity did not show any trends between the treatments, firmness was reduced below 3.0 LAI treatments. Given this experiment, we think that appropriate leaf-area management may be effective for increasing productivity in greenhouse tomato cultivation and that the data on the relationship between leaf area and plant growth of the various tomato cultivars should be further increased by continuous research.