What We Know About Heat Stress in Rubus

Abstract

With over 500 species spread across six continents, members of the genus Rubus can be found in a wide range of geographic and climatic regions (Graham and Woodhead 2011; Jennings 1988; Hall et al. 2009; Hummer 1996). Although there are sources of adaptation to climate extremes in wild germplasm, commercial raspberry cultivars have a limited range of production. Until recently, raspberries were produced primarily in the Western US, and where climates are considered temperate or Mediterranean (Kempler and Hall 2013). However, as the demand for year-round production increased, production expanded to regions including southern Europe, Chile and Mexico. In contrast, blackberry (Rubus spp.) cultivars are considered more widely adapted and perform well in both moderate Mediterranean climates and hot humid climates, however, the newer primocane-fruiting types struggle to produce flowers and fruit in warmer climates. With the advent of more frequent cold and warm temperature extremes that are a part of global climate change, both raspberries and blackberries will have heat stress as a major challenge for growth and expansion of these crops.