Adapting Sunflower to Climate Change by Tapping Variation in Its Wild Relatives

Climate change is predicted to increase the frequency and intensity of environmental stresses such as drought, flooding, heat, and salt, which reduce crop productivity. While many wild species have evolved mechanisms to avoid or tolerate these stresses, crops typically are less resilient. Thus, attention has increasingly turned to crop wild relatives as potential sources of resistance traits. Sunflower is an ideal system for the proposed research because this $20 billion oilseed crop is clearly limited by such stresses, while wild relative species are adapted to a variety of extreme environments. Here we describe progress toward tapping the diversity of sunflower crop wild relatives. As part of a broader project to adapt agriculture to climate change, we assessed the genetic diversity of wild species that are cross-compatible with cultivated sunflower. Wild samples selected to encompass as much genetic diversity as possible were then employed as donors for the creation of circa 400 pre-bred lines, which involved a combination of backcrossing and selfing to establish wild introgressions in a uniform cultivated genetic background. The pre-bred lines were genotyped to determine the number, size and locations of the wild introgressions and evaluated in Uganda, Europe, and Canada. The lines contain promising variation for oil content, as well as tolerance to both biotic and abiotic stresses. Genome-wide association studies further indicate that tolerance to abiotic stresses can sometimes be achieved in sunflower without a negative trade-off with yield under ideal conditions.