Plant water status, plant growth, and fruit yield in bell pepper (Capsicum annum L.) under shade nets

Shade nettings can be an effective technology for producing bell pepper under warm conditions. The physiological mechanisms through which shade nets improve plant growth and fruit yield are still not fully understood. The objectives were to determine the effects of shade level on plant and soil water status, plant growth and fruit yield of 'Aristotle' bell pepper. Trials were conducted in the spring/summer of 2017 and 2018 in Tifton, GA, following a randomized complete block design with five shade levels [0% (open field), 30%, 47%, 63%, and 80%]. Photosynthetic photon flux rate (PPFR) and leaf temperature decreased while soil water content and leaf water potential increased with shade level, indicating reduced plant water use due to reduced evaporative demand under shaded conditions. Increased shade levels resulted in enhanced plant growth in part because of improved plant water status. Total fruit yield and number of sunscalded fruit diminished with increasing shade level, while marketable yield was maximal at 30% shade. The incidences of soil-borne diseases [Phytophthora blight (Phytophthora capsici) and southern blight (Sclerotium rolfsii)] decreased with increasing shade levels. Overall, a shade level of 30% was found to be optimal and allowed production of maximal fruit yield through improving water availability (plant and soil water) and minimizing abiotic (drought, light, temperature) and biotic (pathogens) stresses.