Improved Light Conditions at the Fruit Truss Accelerate Harvest Time and Enhance Ascorbic Acid Concentration in a Low-truss, High-density Tomato Production System

Abstract

Light conditions are poor around the lower trusses of tomato plants in a low truss number, high plant density production system. We determined the effects of leaf rearrangements above the fruit trusses on fruit maturation and quality in tomato plants pinched above the third truss and cultivated under a high-density growing system. Integrated solar radiation at first and second fruit trusses and surface temperature of fruits at second fruit truss were increased in plants treated with leaf rearrangements above the trusses compared with those of the control, and the maturation of fruits at the third truss treated with leaf rearrangement was 4.6 days earlier than that of the control. The concentration of ascorbic acid (AsA) in fruits of plants treated with leaf rearrangement was higher than that of control fruits. However, leaf rearrangement had no effect on yield and Brix of the fruit. These results indicated that higher solar radiation together with leaf rearrangement promoted fruit maturation and increased AsA content in the fruit of lower trusses of tomato plants cultivated under a low truss number, high plant density growing system.