Effect of LED, UV-B, and fluorescent supplemental lights on plant growth and fruit quality of strawberries grown in a greenhouse and on their infection by Colletotrichum spp.

Authors: Smith, Barbara; REZAZADEH, AMIR - University Of Florida; STAFNE, ERIC - Mississippi State University; Sakhanokho, Hamidou

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/6/2022
Publication Date: 3/13/2022
Citation: Smith, B.J., Rezazadeh, A., Stafne, E., Sakhanokho, H.F. 2022. Effect of LED, UV-B, and fluorescent supplemental lights on plant growth and fruit quality of strawberries grown in a greenhouse and on their infection by Colletotrichum spp.. Meeting Abstract. https://doi.org/10.21273/HORTSCI16591-22.
DOI: https://doi.org/10.21273/HORTSCI16591-22

Interpretive Summary:

Technical Abstract: Supplemental lighting is used to extend daylength for strawberries grown in greenhouses and high tunnels; however, information is limited on the effect of these lights on disease development and pathogen growth. We evaluated the effect of 6 supplemental light treatments (red, blue, white, and combination LED; wide spectrum fluorescent (WSF); and WSF+UV-B) on plant growth, fruit quality, and disease development of strawberries grown in a greenhouse. Plants received natural light supplemented by 17 hours of treatment lights. Plants in the WSF+UV-B treatment also were exposed to UV-B light for 3 h during the dark period. Light treatments were replicated 3 times and included 4 plants each of 6 strawberry cultivars (Camarosa, Chandler, Pelican, Seascape, Strawberry Festival, and Sweet Charlie). After 4 and 5 months exposure to light treatments, detached leaves from each cultivar in each light treatment were inoculated with the anthracnose pathogen, Colletotrichum gloeosporioides and rated for disease severity 10 days later. There were significant (p < 0.05) effects of light treatments on photosynthetic photon flux density (higher in red and combination LED light treatments), relative chlorophyll content (plants in the combination and red LED light treatments had the lowest SPAD readings), flower number (plants in the blue LED treatment had more flowers than those in the combination LED treatment), plant size (plants in the blue, combination, and red LED light treatments were larger and denser than plants in the WSF and WSF+UV-B treatments), plant injury (plants in the combination and red LED treatments displayed more severe injury possibly due to the intensity of the red LED light), and elemental leaf analysis (plants in the WSF+UV-B and WSF had higher levels of N, P, K, Ca, Mg, Fe, and Zn levels and those in the combination and red LED treatments had the lowest levels). There was not a significant (p = 0.05) effect of light treatments on Brix or titratable acidity levels of fruit or in disease severity ratings following inoculation with C. gloeosporioides. In most parameters assessed, there was a significant effect due to cultivar, but not a significant light treatment by cultivar interaction. This study shows that supplemental light affects strawberry plant growth but not fruit quality or disease severity.