True colors shining through: how low tunnel cover colors affect fruit yield and photosynthesis in strawberry cultivars

Light significantly influences strawberry photosynthesis, growth, and yield. Consequently, there is a growing use of light-modifying materials to enhance crop productivity. However, the effects of low-cost, colored plastic films on strawberry photosynthesis and fruit yield remain unexplored, despite previous testing of light-altering materials in other vegetable crops. This study aimed to evaluate the effects of different colored plastic films used as low tunnel covers on the yield and photosynthetic capacity of two strawberry cultivars. Plants from the short-day ‘Camarosa’ and the day-neutral ‘Albion’ cultivars were grown under low tunnels. The tunnels were either covered with transparent, opaque, blue, green, red, and yellow plastic films or with no cover (control), in a 7 × 2 factorial scheme (tunnel covers × cultivars). Photosynthetic pigment content, gas exchanges, chlorophyll a fluorescence, and yield were evaluated. ‘Albion’ produced twice more than ‘Camarosa’, with ‘Albion’ showing a higher yield under transparent, opaque, red covers and without a cover (control) compared to the blue-, green-, and yellow-covered counterparts. The yield of ‘Camarosa’ was not affected by tunnel cover, and its photosynthetic capacity in response to tunnel covers was highly variable. Different tunnel cover colors affected the photosynthetic capacity of the Albion cultivar, with opaque cover resulting in higher photosynthetic capacity. These results may shed light on the use of tunnel covers to optimize photosynthesis and yield in strawberry cultivars.