Climatic conditions found in high tunnels of the Upper Midwest have shown adverse effects to primocane red raspberry growth and development. Photosynthetically active radiation (PAR) greater than 600 µmol·mˉ2sˉ1 has been found to decrease shoot growth, fruit quality and yield, and contribute to the onset of premature bud dormancy. Researchers also found as air- and root-zone temperatures exceed 75°F and 60°F, respectively, reduced yield, berry weight, and berry quality may result. The proposed study was intended to conclude results taken from 2012 and 2013, with an additional year of data taken on fully established canes in 2014. Our objectives were to 1) assess the relationship between PAR and temperature and their effect on primocane development, and 2) evaluate the efficacy of shade cloth and soil mulch in reducing PAR and root-zone temperature during high tunnel primocane red raspberry production.
Iowa State University
Riesselman, Leah and Nonnecke, Gail, "Photosynthetically Active Radiation and Root-zone Temperature Effects on High Tunnel Primocane Red Raspberry Development" (2015). Iowa State Research Farm Progress Reports. 2171.