Assessing crop genetic resources for climate change adaptation using crop and climate models.

摘要

Many scenarios of crop yield under climate change have been developed using crop and climate models. Projections of changes in yield, and estimates of associated uncertainty, differ between studies. This paper presents scenarios of crop yield for India for which uncertainty has been quantified objectively. These scenarios are used to assess the extent to which genotypic variation can be used to adapt to climate change. The requisite crop genetic properties are then compared to those of existing germplasm. The methods shown can be used across the globe and for a range of crops, thus indicating the capacity inherent in current germplasm for adaptation to climate change. One topic that emerges from the study is the interaction between water stress and CO₂. From a physiological perspective, water-stressed crops are expected to show greater CO₂ stimulation than well-watered crops. This expectation has been cited in literature as a reason for believing that rainfed cropping systems will benefit more from elevated CO₂ than irrigated systems. Free-Air CO₂ Enrichment (FACE) meta-analyses are reviewed, and crop modelling results presented, in order to assess this expectation. A greater response of water-stressedcrops over well-watered crops is not seen consistently in either the FACE studies or in the crop models. Detailed analysis leads to the preliminary conclusion that the relationship between water stress and assimilation may vary with spatial scale. Thisis the abstract of the presentation to be given at the conference.