Photoperiodic influence of light-emitting diode (LED) on vegetative parameters of Spinacia oleracea L. (Spinach)

This research aims to determine sustainable strategies to optimize crop growth and yield, by testing the possibilities of using light-emitting diode (LED) technique to influence the vegetative parameters of spinach. A speed-breeding chamber was constructed using LEDs as a light source under varying photoperiods (19, 17, 15, and 13 hours). The control was established to be the normal light duration of 11 hours during the study period. Spinach vegetative parameters involving morphological parameters such as stem length, root length, and leaf area as well as physiological parameters such as plant weight and percentage necrosis and chlorosis were investigated for 30 days after transplanting. The results showed a significant (p 0.05) increase in morphological parameters of spinach with increasing photoperiod. The spinach plant under the long photoperiod was observed to show the highest morphological and physiological properties. About a 30% increase in root length was observed in the speed-breeding chamber with the longest photoperiod duration compared to the control conditions. Significantly improved spinach plant weight was observed for 19-hour photoperiod compared to the shorter exposure (p 0.05). A lower percentage of necrosis and chlorosis was observed in spinach with longer LED exposure. This research indicated that LED-induced speed breeding is very effective in improving the vegetative properties of spinach. It can be argued that a 19-hour LED-induced photoperiod is the optimum photo duration required by spinach to improve vegetative growth. Future research should be conducted to investigate the influence of similar LED-induced photoperiods on other species of vegetables. Keywords: breeding chambers, light-emitting diode, photoduration, photoperiodic influence.