Field-Based Characterization of Crop Responses to Temperature.

Research quantifying how plants respond to temperature date to the 1700s. Nonetheless, there is still large uncertainty concerning the shapes of specific thermal responses and their associated cardinal temperatures. This uncertainty is problematic for many areas of crop research but is especially vexing in attempts to simulate the potential impacts of climate change on crop production. Issues of concern include how thermal responses differ among physiological processes, how acclimation affects such responses, and how large are inter- and intra-specific genetic differences. Controlled environment studies have long been considered the most reliable source of data on temperature responses. However, crop research requires understanding how plants respond at the community scale, where temperature, humidity and radiation regimes differ greatly from those imposed in controlled environment. While field research presents numerous challenges, improvements in instrumentation, manipulative techniques, and analyses make field-based studies increasingly attractive. We review results from field-based temperature studies. Challenges include ensuring an adequate number and range of temperature regimes and understanding how observed responses are affected by local climate, especially humidity, and by the methods used to characterize the temperature regimes.