DropXL Sorghum, a simulation study to design crop trait technology for water productivity in Kansas environments
Rubi Raymundo, Sandeep Marla, Terry Felderhoff, Sarah Sexton-Bowser and Geoffrey Morris
Department of Agronomy, Kansas State University
DropXL Sorghum is a State of Kansas effort managed by the Collaborative Sorghum Investment Program to advance sorghum technology for the benefit of farmers and Kansas water resource stakeholders. The trait technology package provides farmers with sorghum technology for higher productivity under moderate water limitation. DropXL will identify optimal trait combinations for water productivity across Kansas’ target environments (Trait Map), identify genetic markers for targeted trait in field trials (Trait Marker), and develop improved trait donor lines to facilitate water-optimized sorghum hybrids (Trait Donor). The first phase deliverable is a trait map with informing by a study simulating combinations of crops traits and Kansas environments. A sorghum with a chilling tolerant trait has potential to extend the growing season to better synchronize the crop water demand and water availability. In addition, a sorghum with a limited transpiration trait has the potential to reduce the crop transpiration in hours with high evaporative demand resulting in conservation of soil water for use during late season. Crop ecophysiological models that simulate the crop response as a function of genotype (G), management (M) and environment (E) are common tools to assess the impact of genetic traits in a range of scenarios. In this study, we used the APSIM-Sorghum crop model to quantify the potential benefit of chilling tolerance (CT) and limited transpiration (LT) trait, across Kansas. Simulation experiments were conducted under rainfed conditions in Colby, Garden City, Hays and Manhattan from 1986 to 2018. The crop was simulated to be grown every year in three planting dates: mid-April (Early planted), mid-May (Early planted) and mid-June (Early planted). In every planting date, we analyzed the variability of precipitation, soil moisture and predicted yields. Our results suggest that a standard grain sorghum hybrid with a CT trait could escape drought and have higher yields (~5%) if planted 30–60 days early (mid-May to mid-April). Similarly, a grain sorghum with a LT trait may have potential to increase grain yields by 4% with a balance of using soil moisture in periods of stress and conserving for moisture availability through the entire season. Overall, these simulations offer encouragement that genetic improvement in sorghum with the introgression of CT and LT trait are likely to make valuable economic contributions to the communities in Kansas supported by agricultural productivity. This knowledge informs the continuing research and development of the DropXL trait technology package.