Table 2. Description of integrated traits (APSIM-Wheat output variables) and environmental indices included in the analysis.

Environment indices were computed for the sowing-harvest period, for all considered environments. Water-deficit index correspond to the simulated water supply-demand ratio and relates to the degree to which the water available to the roots matches the plant water demand [7]. Nitrogen stress index relates to the level of nitrogen stress on photosynthesis. Stress indices are expressed as scalars so that values range from 0 (low stress) to 1 (high stress).

Type	Variable	Description	Unit
Crop	Flowering	Flowering date	day
Crop	Maturity	Maturity date	day
Crop	LAI	Leaf area index at flowering	-
Crop	Grain Size	Dry biomass of an individual grain	g
Crop	Grain Number	Grain number	grain
Crop	Grain Protein	Grain protein content	%
Crop	Biomass	Crop aerial dry biomass at harvest	t ha-1
Crop	Yield	Crop grain yield at harvest	t ha-1
Environment	Water	Average soil water deficit ratio	-
Environment	Nitrogen	Average nitrogen stress factor	-