Photoselective Shade Netting in a Sweet Pepper Crop Accelerates Ripening Period and Enhances the Overall Fruits Quality and Yield

Photoselective nets are used to protect horticultural plants from sunburn and prolong the cropping period in conditions of excess light. In this work, we studied the influence of four photoselective shading nets (Pearl 30, Red 30, Silver 30, Red 40), a standard black-colored net (Black 35), and a control (no cover) on the evolution of color during the ripening of two types of pepper, namely, Lamuyo and California. For this purpose, the evolution of the colors of the fruit was followed from the beginning of their formation until the harvest, and was correlated with the total radiation and the temperature. The plant material used were peppers of the California type -cultivars Bendigo and Cayetano- and of the Lamuyo type, cultivars Alcudia and Pompeo. The results showed that the rate of change of the pepper coloration depended on the net used in the greenhouse. The speed of the change in color from green to red was more dependent on the cultivar and the total radiation, as conditioned by the different photoselective nets, than on the type of pepper. The greatest differences were between the control (without a net) and the black net, the increase in the red color of the peppers being faster in the former. Radiation values below 75 W m-2 or greater than 110 W m-2 negatively affected the yield. The temperature below the net was not affected significantly by the type of net, and thus its effect on the different cultivars was similar.