2019 ASHS Annual Conference

Colored shade nets have shown benefits in bell pepper and other horticultural crops in Israel and other countries, although there is little information on use of colored shade nets on bell pepper in the U.S. The objective was to determine the effects of colored shade nets on fruit yield and quality of bell pepper. The study was conducted at the Horticulture Farm, Univ. of Georgia, Tifton, GA, during the spring of 2015 and 2016 in a sandy loam soil. Bell pepper (‘PS 09979325’) plants were grown on drip-irrigated raised beds; beds covered with black plastic film mulch. Each shade net was placed on a wooden rectangular structure (15 m wide x 6 m long x 5 m high). Experimental design was a randomized complete block with four replications and five treatments [5 shade treatments (black, red, silver, white, and uncovered)]. Results showed that mean and maximal air temperature and midday root zone temperature were highest in the unshaded treatment. Plant growth, measured as plant height and stem diameter were reduced in the unshaded treatment, although plant growth was unaffected by the shade net color. Leaf temperature was highest in the white and the unshaded treatments. Marketable and total fruit number and yield and individual fruit weight were reduced under unshaded treatment compared to all shading nets. The effects of colored shade nets on marketable fruit number and yield varied in the two year. in 2016, highest marketable yields were under silver net. The effect of shade nets on fruit soluble solids, total phenols, flavonoids, and antioxidant composition measured as CUPRAC (Cupric Reducing Antioxidant Capacity ) and TEAC (Trolox Equivalent Antioxidant Capacity) also varied by year, although fruit under unshaded conditions had increased total phenols, flavonoids, and TEAC values. In conclusion, there were no consistent differences in bell pepper fruit yields among colored shade nets. Plant growth and fruit yield were reduced and fruit content of antioxidant compounds increased under unshaded conditions in both seasons.