Response and Adaptation of Crops and Weeds to Climate Change.

Weeds represent the largest global biotic constraint to achieving maximum crop yields.  The bulk of published studies to date indicate that global climate change, specifically rising CO₂ levels and warming temperatures have favored weed growth and fecundity over the crop, with negative consequences for weed-crop competition and crop production.  However, many of the most competitive weeds are often genetically related to the crop (e.g. oat and wild oat, rice and wild rice, sorghum and shattercane, potato and nightshade, inter alia).  As such, the greater adaptability and resiliency of the wild, weedy relatives to changing environmental conditions and rising CO₂ levels could serve as the basis to begin genetic and phenotypic improvement of crop production.  In this regard, I will highlight our ongoing work on weedy and cultivated rice in the context of rising atmospheric CO₂ and air temperature as a test case to illustrate both the negative consequences for crop loss, and the potential for inclusion of wild rice lines to broaden genotypic and/or phenotypic variation as a means to adapt rice production to a changing climate.