Fruit Quality Response to Different Abaxial Leafy Supplemental Lighting of Greenhouse-Produced Cherry Tomato (Solanum lycopersicum var. Cerasiforme)

Abstract

Insufficient light supply for canopies is a constant issue during greenhouse production in most areas of Northern China. Applying supplemental lighting to plant canopies is an efficient method of solving this problem. Several studies were conducted to identify the optimal, economically efficient abaxial leafy supplemental lighting mode to produce high-quality greenhouse tomatoes. In this experiment, no supplemental treatment was used as a blank control (CK), while three supplemental lighting modes were used as treatments: T1, continuous supplemental lighting from 8:00–9:00 (at GMT+8, which is 6:00–7:00 local time, before the thermal insulation covers, abbreviated as TIC below, opening), and 20:00–22:00 (after TIC closing) with photosynthetic photon fluxion density (PPFD) of 200 μmol·m−2·s−1; T2, dynamic altered supplemental lighting with PPFD rising from 100 μmol·m−2·s−1 to 200 μmol·m−2·s−1 before TIC opening and falling from 200 μmol·m−2·s−1 to 100 μmol·m−2·s−1 after TIC closing; and T3, intermittent supplemental lighting which was automatically conducted with PPFD of 100 μmol·m−2·s−1 when indoor PPFD below 150 μmol·m−2·s−1 from 8:00–22:00. The results demonstrated that abaxial leafy supplemental lighting treatment could improve both fruit yield and quality. The total yield in the T1 and T2 treatments was higher than in other treatments, though there was no significant difference. Differences in leaf carbon exportation showed the possibility of determining fruit yield from the 3rd leaf under the fruit. The overall appearance, flavor quality, nutrient indicators, and aroma of cherry tomato fruits under T1 and T2 treatments were generally higher than in other treatments. Correlation analysis of fruit yield and quality parameters suggested that they produce relatively high yield and fruit quality. Combined with a cost-performance analysis, dynamic altered supplemental lighting (T2) is more suitable for high-valued greenhouse cherry tomato production.