Grain Number and the Response to Increasing Temperatures in Wheat.

Wheat annual production oscillates among the first top three crops in the world (alongside corn and rice). At the paddock level, wheat yield is mainly associated to grain number per unit area, a yield component very responsive to temperature. Predicted rising temperatures (IPCC, 2007) are forecast to lower wheat production by limiting the length of the growing season and by exerting direct negative effects on resource capture and on processes underpinning growth and yield. In this paper, we investigate the quantitative response to increasing temperatures of wheat floret and grain generation and survival, as well as the traits underpinning these processes, based on a series of field and glasshouse experiments. In addition, we explore the role of genotypic variation on spike fertility in relation to temperature.