Responses of Winter Wheat Yields to Warming-Mediated Vernalization Variations Across Temperate Europe

Abstract

Rapid climate warming, with much higher warming rates in winter and spring, could affect the vernalization fulfillment, a critical process for induction of crop reproductive growth and consequent grain filling in temperate winter crops. However, regional observational evidence of the effects of historical warming-mediated vernalization variations on temperate winter crop yields is lacking. Here, we statistically quantified the interannual sensitivity of winter wheat yields to vernalization degree days (VDD) during 1975-2009 and its spatial relationship with multi-year mean VDD over temperate Europe (TE), using EUROSTAT crop yield statistics, observed and simulated crop phenology data and gridded daily climate data. Our results revealed a pervasively positive interannual sensitivity of winter wheat yields to variations in VDD ($γ$VDD) over TE, with a mean $γ$VDD of 2.8 $±$ 1.5 kg ha-1 VDD-1. We revealed a significant (p < 0.05) negative exponential relationship between $γ$VDD and multi-year mean VDD for winter wheat across TE, with higher $γ$VDD in winter wheat planting areas with lower multi-year mean VDD. Our findings shed light on potential vulnerability of winter wheat yields to warming-mediated vernalization variations over TE, particularly considering a likely future warmer climate. © 2017 Wu, Liu, Li, Tian and Mahecha.