In water-limited environments, water is the main limiting factor of crop production, especially in rainfed crops such as durum winter wheat (Triticum durum Desf). Consequently, also in climatic change projections, it is essential both to recognise characteristics in breeding programs that can lead to drought tolerance and to reduce the time needed to observe variations of these traits on crop yield. Moreover, changing in management strategies could improve crop adaptation to climate change, not considered in this approach. Crop growth models can assist breeding research in identifying these traits. The CropSyst model was parameterized for durum wheat cultivated in Southern Italy: crop characteristics were analyzed, development (grain filling duration and phenologic response to water stress), canopy expansion (specific leaf area, leaf duration and ratio between leaf and stem) and water uptake (root length). Model sensitivity was evaluated varying one parameter at a time and changing the value by +/-5, +/-10 and +/-20% of calibrated values. Wheat was simulated with past real daily climatic data (55 years, from 1952 to 2006) and future daily climatic data predicted with an HADCM3 global climatic model (100 years, from 2000 to 2100) where an average air temperature increase of +2 degrees C is expected as well as a CO2 concentration of 550 ppm (IPCC, A2 scenario). Leaf area duration and specific leaf area proved to be the parameters with the greatest impacts on wheat yield, with changing in wheat yield from -20 to16% and from -38 to 35% respectively as consequence to variation for these parameters oscillating between 20 and 20%. The ratio between the leaf and the stem biomass accumulation was inversely and linearly related to grain yield. Lengthening or shortening the grain filling duration did not seem to provide benefits in term of grain yield. The non-response in term of grain yield to water stress highlights that the wheat crop was optimized yet in Mediterranean environment in order to maintain production stability in drought conditions which could accelerate different crop phenological stages. The variation of maximum root depth (from 0.8 to 1.2 m) did not result in any significant variation in grain yield. The changes of crop morphology could also enhance climate change adaptation.
Garofalo, P; Rinaldi, M
Modelling phenotypical traits to adapt durum wheat to climate change in a Mediterranean environment
Italian Journal Of Agrometeorology-Rivista Italiana Di Agrometeorologia