Optimizing production of tomato seedlings ‘Florida 47’ and ‘Shin Cheong Gang’ for grafting using lower DLI and CO₂ supplementation in precision indoor propagation systems

Grafted tomato seedlings are commonly used to combat various stresses and improve yields.
Propagation of grafted tomatoes is difficult and labor intensive.
In addition, low conversion efficiencies, low plant uniformity, and lack of consistent quality are common challenges when the environmental conditions in the greenhouse are not uniform.
Precision indoor propagation (PIP) are enclosed propagation systems that precisely control environmental factors to affordably increase young plant quality and production.
PIP systems rely on electrical lighting as the sole source light for photosynthesis which contributes to a high energy consumption and operational cost.
CO₂ supplementation is an inexpensive method to increase growth in systems with low room air exchange.
The objective of this experiment is to use elevated CO₂ to reduce the light requirements for production while maintaining the same growth and quality of tomato seedlings.
Two cultivars were grown; scion ‘Florida 47’, and rootstock ‘Shin Cheong Gang’. Plants were subjected to three different light treatments 6.5 DLI (6.4±0.3), 9.7 DLI (9.6±0.5), and 13 DLI (12.8±0.6) daily light integral (mol m^‑2 d^‑1) along with three different CO₂ treatments 400 CO₂ (439±23) (ambient), 1000 CO₂ (1018±42), and 1600 CO₂ (1589±10) μmol mol^‑1. The room air temperature was 22.4°C (average), and 52±8.2% RH. Seedlings were grown until 1.8-2.0 mm stem diameter.
Daily and final morphological and growth rate measurements were taken.
Results show that under 13 DLI and 1600 CO₂, ‘Florida 47’ seedlings reached grafting stage at day 16, 11% earlier than the control (13 DLI and 400 CO₂). ‘Shin Cheong Gang’ grown at 13 DLI and 1600 CO₂ reached grafting stage at day 15, 12% earlier than the control (13 DLI and 400 CO₂). Plants grown under 1600 CO₂ with 30-40% less DLI had comparable growth than plants grown with 13 DLI at ambient CO₂.

International Symposium on Advanced Technologies and Management for Innovative Greenhouses: GreenSys2019

B. Huber, R. Hernández

controlled environments, vegetable grafting, carbon dioxide, LED, DLI, PPF

https://doi.org/10.17660/ActaHortic.2020.1296.35