COLORED PLASTIC COVERS AND ITS RELATIONSHIP WITH RADIATION, GROWTH AND YIELD OF A SWEET YELLOW PEPPER (Capsicum annuum L.) CROP.

Abstract

The roof color of tunnels and greenhouses can modify the spectral characteristics of solar radiation and affect the development and performance of plants. The objective in this study was to evaluate the effect of the color cover of a tunnel on the magnitude and characteristics of radiation on a sweet pepper culture (Capsicum annuum L.) and its relationship with chlorophyll content, growth and yield. This study was carried out in four tunnels covered with red, blue, and translucent polycarbonate and high-density diffuse polyethylene. The spectral properties of the radiation under each cover were determined with a spectroradiometer. The radiation effects on the growth and yield of plants were evaluated in a completely random design with sub-sampling in five treatments (covered tunnels and open field), three repetitions and three samples (plants) per replicate. The Tukey test (p?0.05) was used for means comparison. The photosynthetically active radiation (PAR) transmitted under each cover during the crop’s growth cycle was of 79.22, 53.40, 49.52 and 23.35% for the translucent polycarbonate, high density diffused polyethylene, blue polycarbonate and red polycarbonate, respectively. The transmissivity wavelength ranging from 400 to 550 nm in the red polycarbonate was almost null. Therefore, plants under the red cover had a greater plant height and leaf area, but lower fruit yield. The highest fruit yield was under the high-density diffused polyethylene, due to its greater diffusivity and PAR penetration in the plants foliage.