The food supply is dependent on the ability of plant species to survive in a wide variety of environments. Most crops emerged from limited geographical ranges but were rapidly disseminated into highly variable conditions across the globe. Though selection of crop varieties best adapted to specific locales is critical for maximizing agricultural yields, our understanding of the genetic basis of crop adaptation remains in its infancy. This is partly because the process of plant adaptation occurs over the course of decades making it difficult for plant geneticists to study. To directly observe the process of adaptation, this project will use the barley composite crosses (CCs) common garden experiments, a novel series of agricultural genetics experiments begun nearly a century ago in barley. In these experiments, genetically diverse sets of barley varieties were competed in multiple locations over the course of decades. Using modern genomics techniques, this project will uncover and link the genes that underlie competitive ability revealed in these experiments to changes in important agricultural traits such as flowering time, plant size, and yield. Through this project, hundreds of undergraduate students will participate in the discovery of genetic shifts in the population as part of a reenvisioned introductory biology curriculum that involves hands-on experiments using molecular biology techniques. Plant materials, phenotypic observations, and billions of DNA sequences produced by this project will be made rapidly available for use by researchers and small grains breeders world-wide.
The longevity of the composite crosses makes them an unparalleled genetic resource to study the molecular basis of crop adaptation. The primary goals of this project are to identify genes that underlie crop fitness in variable environments, to explore the genetic process of adaptation over time, and to understand how molecular changes translate into phenotypic differences. To achieve these goals, structural and single nucleotide variants that segregated at the beginning of the experiments will be identified by resequencing the genomes of the forty parental barley cultivars using long read sequencing technologies. The evolution of these variants will be monitored as the composite cross populations adapt to two distinct environments, one located in Bozeman (MT), the other in Davis (CA). Using this comparative approach will allow for the characterization of the rate and mode of genetic change throughout the genome and will result in the identification of suites of genes that drive increases in barley fitness. Finally, genotypes will be linked to phenotypes by creating and using a powerful new barley multiparent mapping population from the composite cross material to identify the genomic basis of numerous adaptive traits, to link changes in gene expression to changes in phenotype, and to reveal how the genetic architecture of trait variation shapes adaptive evolution.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
