Strengthening the foundation of maize agriculture through rational design of root systems

Actualizing maize root system ideotypes toward more sustainable crop production has been hindered by a gap in understanding the genetic basis of root traits and their interactions with the environment. A lack of adequate phenotyping tools to measure root system complexity has contributed to this gap by limiting full exploration of the phenotype space. I will describe our efforts to develop more effective root phenotyping tools in controlled environments and in the field, and to use them in large-scale genome-wide association and other genetic studies, which has allowed us to identify genes that control traits potentially advantageous to root system function. I will describe some of these genes and what we know so far about their performance in the field. Along with several recent discoveries by colleagues, our collective understanding of the genetic basis of maize root system architecture has leapt forward in recent years. With concomitant advances in gene editing and plant transformation, we are on the cusp of rational design and testing of root systems and their actual, rather than theorized, functions. Near-term challenges are to determine how to best leverage this knowledge for future climate and cropping system goals. For example, can we increase the compatibility of maize root systems with cover or relay crops? Can we manipulate root systems to shift the edaphic food web to reduce nitrogen loss and pollution, and to sequester carbon? The time is now to move our basic research discoveries into real-world solutions.