The complete reference genome of Tartary buckwheat and its mutation library provide important resources for genetic...

Tartary buckwheat (TB), Fagopyrum tataricum, is an important medicinal and edible crop with a worldwide distribution. However, reference genomes with gaps and mutant population scarcity have hindered functional genomics and genetic improvement of TB. Here, we present a telomere-to-telomere (T2T) gap-free genome assembly of the elite TB inbred line Guiku1 and its ethyl-methyl-sulfonate (EMS)-induced phenotypically rich mutation library. The Guiku1 gap-free genome spans 453.83 Mb, containing 43,441 predicted protein-coding genes. The mutation library includes 751 mutants with stably heritable phenotypes. Whole-genome resequencing of 320 mutants identified 105,682 single-nucleotide polymorphisms (SNPs) and 21,461 insertions/deletions (indels), affecting the protein-coding sequences of 25,986 genes. Genes responsible for the pink stem and petiole mutant trait and flavonoid content variation were identified using forward- and reverse-genetics approaches, respectively. Collectively, the T2T gap-free genome of Guiku1 and its EMS mutation library provide important resources for functional genomics studies and the genetic improvement of TB.