Supplemental LED Increases Tomato Yield in Mediterranean Semi-Closed Greenhouse

Abstract

Supplemental light (SL) is a technique used to increase horticulture yield, especially in northern countries, where the Daily Light Integral (DLI) is a limiting factor during fall and winter, and which could also be used to obtain higher tomato yield at the Mediterranean latitude. In this study, three tomato hybrid (F1) cultivars were grown for year-round production in a commercial semi-closed glasshouse in Southern Italy: two of the cherry fruit-type (‘Juanita’ and ‘Sorentyno’) and one mini plum fruit-type (‘Solarino’). From 120 to 243 days after transplant, light-emitting diode (LED) toplights were used as SL, with a photoperiod of 18 h. The main climatic parameters inside and outside the glasshouse were recorded, and tomato plants’ development and yield were examined. Plants grown with LEDs had longer stems as compared to control treatment (9.53 vs. 8.79 m), a higher stem thickness and yielded more trusses. On average, the yield was 21.7% higher with LEDs. ‘Sorentyno’ was the cultivar with the highest cumulated productivity when it was grown under SL. However, the cultivar with best light use efficiency under LEDs was ‘Solarino’. Therefore, supplemental LED from mid-December until March enhanced tomato growth and yield, opening a favorable scenario for large-scale application of this technology also in the Mediterranean area.

Supplementary Light Differently Influences Physico-Chemical Parameters and Antioxidant Compounds of Tomato Fruits Hybrids

“…Light treatments (LEDs + natural light and only natural light) were separated into two different glasshouse compartments (with three blocks (replicates) to avoid all possible negative interaction between them (i.e., shadowing, microclimate, pests, and disease outbreaks). More detailed information about experimental set-up has been described by Palmitessa et al [ 9 ].…”

“…The rockwool slabs were placed on metal gutters (length 100 m, width 0.20 m, 0.15% sloped). Crop operations were described by Palmitessa et al [ 9 ]. During the experimental activity, greenhouse day temperature was 22.5 ± 2.32 °C, while night temperature was 17.7 ± 2.21 °C; the average 24 h relative humidity was 67% ± 0.05% and the average CO 2 concentration during the day was 482 ± 77.52 mg L −1 .…”

“…In Southern Italy, because of low DLI integral levels during winter period, it is common to arrest tomato cultivation during this time interval, thus reducing the annual yield [ 8 ]. On this regard, Palmitessa et al [ 9 ] reported that using LEDs as SL source in a Mediterranean semi-closed greenhouse it is possible to increase by more than 25% the tomato yield. At the same time, it is important to maintain fruit quality and nutritional values.…”

“…In our previous research [ 9 ] it was found that R + W + B LEDs increased the yield of three tomato hybrids grown in an innovative commercial semi-closed greenhouse in Mediterranean basin. This work is a direct continuation of the previous one and aims at obtaining more insights into the effects of the SL system of the fruits of three tomato commercial typologies (cherry, red plum, and yellow plum) selected among those already grown in the crop cycle conducted in Palmitessa et al [ 9 ]. In particular, the ability of LEDs toplight to preserve and/or improve the nutritional values and the chemical composition of the selected tomato hybrids has been here investigated.…”

LED Lighting Strategies Affect Physiology and Resilience to Pathogens and Pests in Eggplant (Solanum melongena L.)

“…In northern latitudes, solar light levels during the winter can be insufficient to maintain production levels and product quality, due to the low light intensities and short photoperiods ( Davis and Burns, 2016 ). The potential of supplemental lighting to foster off-seasonal production in the Mediterranean region is also now under investigation ( Palmitessa et al, 2020 ; Paucek et al, 2020 ). Under low-light conditions, natural light can be supplemented by artificial lighting, with high pressure sodium (HPS) fixtures currently being the predominant greenhouse lighting source.…”