After-effect of light-emitting diodes lighting on tomato growth and yield in greenhouse.

The objective of our studies was to evaluate growth, development and yielding of tomato in greenhouse, which transplants were grown under various combinations of light-emitting diodes illumination. Tomato transplants were grown in phytotron chambers. System of five high-power solid-state lighting modules with the main 447, 638, 669 and 731 nm LEDs were used in the experiments. Supplemental LEDs of different wavelength were used in particular modules: LI - without additional LEDs, L2 -380 nm, L3 -520 nm, L4 -595 nm, L5 -622 nm. The similar photon flux density (PFD) in all modules was maintained by regulating PFD of 638 nm LEDs. Tomato seedlings were transplanted to peat substratum and grown in greenhouses. It was established that significant effect of illumination using different LEDs combination on growth and development of tomato hybrid 'Raissa' F1 transplants remained about one month after moving tomato to greenhouses. After-effect on photosynthesis pigments system of tomatoes in greenhouses lasted two weeks. Neither of light-emitting diodes combination had significant effect on early tomato yield. Yellow light, supplemental for the main LEDs combination, used for transplant illumination, decreased total tomato yield. [ABSTRACT FROM AUTHOR]