Genetic architecture of water use efficiency in bioenergy Sorghum and Setaria
P.BHANDARI , C.LUEBBERT, P.OZERSKY, J.BARRETT, G. ZIEGLER, T.C.MOCKLER, I. BAXTER DONALD
Danforth Plant Science Center, Saint Louis, MO 63132, USA

Improving water use efficiency (WUE) is crucial for the economic viability and agricultural sustainability of bioenergy feedstocks. However, genetic mapping of WUE and related traits from field trials remains challenging due to the low throughput and environmental variability in field conditions. To overcome these limitations, this study employs a high capacity, high-throughput phenotyping in a controlled environment to quantify plant biomass and water use in association mapping populations of Sorghum bicolor, a key bioenergy crop, and Setaria viridis, a model species for investigating WUE in C4 grasses. We analyzed over 11,000 plants, from 10 experiments, at daily intervals under well-watered and water-limited conditions and used 580 and 438 Sorghum and Setaria genotypes respectively for Genome-wide association (GWA) mapping. GWA mapping in both species identified numerous genomic regions associated with WUE. Meta-analysis of the GWA summary identified loci significant in multiple populations. Additionally, synteny analysis was done to identify genomic regions conserved between the two species. Syntenic genes detected in the meta-analysis were used to select candidate genes for functional validation. This research enhances our understanding of the genetic architecture of WUE in bioenergy Sorghum and Setaria, with potential implications extending to many C4 grasses.