The Effects of Indoor Light-Emitting Diodes on Sweet Pepper Seedling Growth and the Yield per Plant

Abstract

Pepper is a widely cultivated vegetable, whose growth and development are significantly influenced by various light wavelengths. This paper aimed to examine the effects of different light treatments on the growth of pepper seedlings and their development and yield after transplanting into the greenhouse. As a plant material, we used a commercial sweet pepper of the Morava genotype. In the phenophase of the first permanent leaf formation, plants were placed in closed plant growth chambers under the following treatments: full-spectrum white light-emitting diodes (W-LEDs) (control group), blue LEDs (B-LEDs), the combination of red and blue LEDs (1:1) (RB-LEDs) and red LEDs (R-LEDs). Plants were cultivated for 20 and 27 days with a photoperiod 12/12h (day/night), at a temperature of 23 ± 2°C. At 20 and 27 days of light treatment, the growth rate of seedling height and plant compactness were calculated. Five uniform pepper seedlings per light treatment were transplanted into bigger plastic pots, removed into the greenhouse, and cultivated for the next 51 and 44 days, respectively, under natural daily light. At 51 and 44 days, respectively, the total number of fruits and yield per plant were measured. Our results indicate that light treatments and length of exposure to light treatments, as well as their interaction significantly influenced seedling growth height rate, while seedling compactness was influenced only by length of seedling exposure to light treatments. The length of seedling exposure to light treatments and its interaction with light treatments during the seedling stage significantly affected the total number of fruits and yield per plant after transplanting into the greenhouse. The highest number of fruits and yields per plant was observed in plants grown under R-LEDs for 27 days