Yield loss and quality degradation of strawberry fruits cultivated under the deficient insolation conditions by shading

Abstract

Deficient insolation conditions (DICs) frequently occur during the winter and early spring season in Korea and negatively affect crop growth. This study was conducted to investigate changes in the yields and qualities of strawberry fruits under DICs that result from an insufficient input of sunlight. To induce DIC, strawberry plants were treated with 40 or 70% shading by covering the plants with curtains during growth in a plastic greenhouse. The shaded plants were cultivated from March to May of 2012. When the strawberry plants were subjected to the shading treatments, their photosynthesis and fruit yields were significantly reduced. Although the mineral element and organic acid contents of the fruits were not affected by the shading treatments, the total nitrogen (T-N) of the stems and roots were noticeably reduced. Furthermore, the shading treatments of the plants also resulted in reductions in the sugar contents and total phenolics of the fruits. In parallel with these observations, the shading treatments were also found to decrease the antioxidant activities of the fruits as measured with the DPPH assay. We suggest that the DIC-induced losses of strawberry fruit yield resulted from the reduced photosynthetic performances of the plants that were caused by insufficient sunlight.