Research on mutation breeding started in the early 1960s by researchers at the Atomic Energy Research Institute, Rural Development Administration (RDA) and several universities in Korea. The Radiation Agriculture Research Institute (RARI) was established in 1966, and studies of mutation breeding using radiation were actively conducted for a while. RARI was merged into the Korea Atomic Energy Research Institute (KAERI) and RDA in 1973, and radiation breeding research was neglected by the two agencies. In the 1980s, the relevant research department was lost, which resulted in a recession period of radiation breeding research. The Advanced Radiation Research Institute (ARTI), under the KAERI, was established to promote radiation research and the industry in 2005, which led to the activation of radiation breeding research. Then, the Radiation Breeding Research Center (RBRC) at the ARTI was established with support of the Ministry of Agriculture, Food and Rural Affairs in 2013. Recently, the importance of seed and genetic resources has been emphasized in Korea, and many institutes, companies and private breeders are interested in mutation breeding. The RBRC is trying to develop advanced radiation breeding techniques and new genetic resources using mutation techniques combined with bio-tech. This is to deal with the loss of biodiversity due to global climate change and environmental degradation, growing global demand for food and bio-energy, and to strengthen the protection for new plant varieties. Approximately 180 new mutant varieties were developed and registered officially in Korea. Recently, new mutant varieties, especially of flowers and ornamental plants, have quickly increased and are being commercialized, mainly by private company and breeders.

A dwarf mutant rice line was selected from an Ac/Ds insertion mutant population and named dwf1. The phenotype of F₁ and F₂ plants derived from a cross between dwf1 and Dongjin indicated that a single recessive gene is responsible for the mutant phenotype, and we named this gene dwf1. Resequencing of the dwf1 line and Dongjin (wild type) revealed 42,386 homozygous single nucleotide polymorphisms (SNPs) between dwf1 line and Dongjin. MutMap analysis was performed by sequencing a DNA pool prepared from 100 mutant type plants in the dwf1/Dongjin F₂ population, and it was found that the dwf1 gene was located in the 23 ~ 30 Mbp region on chromosome 4. In this region, we found a non-synonymous SNP in the Os04g0469800 gene, which was reported as D11 gene encoding a cytochrome P450 family protein involved in the biosynthesis of brassinosteroids (BRs). This SNP was regarded as the causative SNP for the dwf1 phenotype, and the dwf1 gene is a novel allele of D11. We performed mapping of the dwf1 gene with five SNP markers on chromosome 4 with 190 dwf1/Dongjin F₂ plants. The phenotype of F₂ plants was completely co-segregated with genotypes of the J10402 marker, which was developed based on the non-synonymous SNP in the D11 gene. These results will contribute to the study of the molecular biological functions of the D11 gene and BRs.

Gliadin proteins are a major component of gluten proteins and important determinants of bread-making quality by conferring the viscosity and extensibility of dough, but also present significant health problems for consumers with wheat-related diseases like celiac disease or wheat allergies. In order to solve this problem, we conducted RP-HPLC analysis to profile gliadin fractions for screening the mutants deficient in gliadins from 122 wheat doubled-haploid (DH) lines cultivated by the National Institute of Crop Science. Comparing the RP-HPLC chromatogram of 122 DH lines with those of the respective parents, we found that some peaks of omega-5 gliadin were not present in 28 DH lines. Further analysis using SDS-PAGE and A-PAGE showed that the omega-5 gliadin in the parental varieties had two to three bands, but only one band in the absent 28 DH lines. The relative expression levels of all gliadin groups in the parental and mutant lines were also examined by RP-HPLC. Our study contributes to establishing a method for the rapid screening and identification of mutants missing gliadins as major epitopes of wheat-related disease in many wheat genetic resources and breeding lines as valuable information to other researchers.