Spatiotemporal changes of wheat phenology in China under the effects of temperature, day length and cultivar thermal characteristics

Investigating the spatiotemporal changes of crop phenology in field is important to understand the processes and mechanisms of crop response and adaption to ongoing climate change. Here, the wheat phenology at more than 100 national agro-meteorological experiment stations across China spanning the years 1981-2007 was examined. Spatiotemporal changes of wheat phenology and seasonal temperature, as well as the correlations between them were presented. During the investigation period, heading dates advanced significantly at 43 stations from the 108 investigated stations: maturity dates advanced significantly at 41 stations from the 109 investigated stations. Lengths of growing period (from sowing to maturity) and vegetative growing period (from sowing to heading) were significantly reduced at about 30% of the investigated stations, especially for spring wheat in northwestern China, despite thermal accumulation during the periods increased. In contrast, although significantly and negatively related to mean temperature, lengths of reproductive growing period (from heading to maturity) increased at 60% of the investigated stations, owing to increase in crop cultivars thermal requirements or/and decrease in mean temperature. The results showed that besides the complex influences of agronomic factors, climate change contributed substantially to the shift of wheat phenology. Mean day length during vegetative growing period had a decreasing trend at most of the investigated stations owing to delay of sowing date or/and advancement of heading date, which counterbalanced the roles of temperature in controlling the duration of vegetative growing period. In-depth analyses showed that thermal requirements from sowing to almost each development stage increased, however the thermal requirements to complete each single development stage changed differently, which tended to increase yield and adapt to ongoing climate change. Our findings have important implications for improving climate change impact studies, for breeding scientists to breed higher yielding cultivars, and for agricultural production to cope with ongoing climate change. (c) 2012 Elsevier B.V. All rights reserved.