Genetical Process of the Establishment of Rice Local Population

After domestications, many cultivated species are grown under diverse environmental conditions other than their origins. It is unclear whether local populations could establish their adaptability to the specific local environmental conditions. We focused on the rice population grown in higher latitude with specific adaptability. The cultivated rice, Oryza sativa L., which originated from tropical regions, is now grown worldwide due to the concerted efforts of breeding programs. At first, we characterized DNA polymorphisms in the rice variety KITAAKE from Hokkaido, one of the northern limits of rice cultivation in the world. INDEL polymorphisms were attributed to transposable element-like insertions, tandem duplications, and non-TE deletions as the original mutation events in the reference variety NIPPONBARE and KITAAKE genomes. The KITAAKE alleles widely distributed throughout wild rice and cultivated rice over the world. These have accumulated in the local population from Hokkaido via Japanese landraces as the ancestral population of Hokkaido. These results strongly suggested that combinations of pre-existing mutations played a role in the establishment of adaptability. This approach using the re-sequencing of local varieties in unique environmental conditions will be useful as a genetic resource in plant breeding programs in local regions.