Replaying the Tape Across A Century of Crop Adaptation

Plant domestication by ancient farmers typically occurred in a limited geographic area, but trade and migration dispersed these early crops across entire continents. Once introduced to a new locale, crop plants were confronted with novel environments and farming practices. Genetic variation segregating within each field facilitated rapid adaptation by targeting advantageous alleles under local conditions. Understanding the process of environmental adaptation in crops, and the number and types of genes that drive it, has important agronomic implications in a rapidly changing world. However, the long generation times of large, multicellular organisms make it difficult to study the process of adaptation directly. We aim to gain a mechanistic understanding of the molecular underpinnings of crop adaptation through direct observation of evolution. To accomplish this goal, we study a one of a kind series of long-term agricultural experiments, the barley composite crosses. In these experiments thousands of barley genotypes were competed against one another for decades in several environments. By directly observing evolution in the composite crosses we can link individual genetic changes to fitness across time and observe how they are combined into a single genome to facilitate adaptation.