Effects of Temperature and Light in High Tunnel Primocane Red Raspberry Production

Abstract

High tunnel production of primocane red raspberries extendsthe growing season, decreases winter injury, increases cane height and growth rate, and improves overall fruit quality and yield. However, tunnels have the potential to increase light intensity levels and result in high air and soil temperatures, which are detrimental to primocane red raspberry production. Soil and air temperatures above 16°C (60.8°F) and 24°C (75.2°F) and light intensity levels beyond 600 µmol·mˉ²sˉ¹ have been shown to decrease water uptake, encourage premature bud-dormancy, delay time to ripening, and reduce fruit quality and weight. The proposed study is intended to 1) assess the relationship between temperature and light intensity and their effect(s) on primocane raspberry growth and development, 2) evaluate how effective shade cloth and soil mulch are in reducing temperature and light intensity levels of high tunnel red raspberry production, and 3) provide relatively inexpensive solutions to minimize temperature and light intensity damage in protected red raspberry production during the warm summer monthsin Iowa.