Global warming is expected to reduce crop yields in many regions over the coming century, increasing the risk of hunger. Concurrent shifts in crop phenology could counter some of the negative effects of warming on yields, suggests a German-based study of winter wheat.
Ehsan Eyshi Rezaei, of the University of Bonn, Germany, and colleagues examined the effect of temperature change on the first day of heading of winter wheat in Germany, using phenological and climate data collected between 1951 and 2009. Although spring temperatures remained fairly stable during the first half of the measurement period, they rose significantly between 1976 and 2009. This period of warming coincided with a marked advancement in the first day of heading, which moved forward by 14 days over this period. As a result of this acceleration in crop development, heat stress around the time of flowering — which occurs just after heading — increased only slightly over the same period.
The researchers note that although earlier heading may protect winter wheat from heat stress during a key developmental stage, warming could still compromise yields, for instance by reducing the length of the grain-filling period.