Utility of TRAP markers to determine indel mutation frequencies induced by gamma-ray irradiation of faba bean (Vicia faba L.) seeds

Purpose: The aims were to determine the optimal gamma ray dose for faba bean (Vicia faba) and to identify genetic variation and indel mutation frequency among mutants using target region amplification polymorphism (TRAP) markers. Materials and methods: Seeds from 10 elite lines were irradiated with gamma rays (50–700 Gy), and germination, survival rate, and representative morphological traits were measured. The extent of DNA damage was investigated using comet assays, and TRAP markers were used to evaluate genetic variation, genetic diversity, and mutation frequencies. Results: Germination percentages significantly decreased at doses >100 Gy. Survival percentages and morphological traits decreased with elevation in dose. The comet assays revealed that high irradiation doses decreased head DNA levels. Phylogenetic and principal component analysis of 555 individual faba bean plants resolved eight major groups. Genetic variation between controls and mutants was limited to within groups. Mutation frequencies were associated with gamma dose in each mutant line. Conclusions: The optimal gamma dose was 100–150 Gy on the basis of survival percentage and morphological response analysis. The TRAP markers distinguished mutant lines and showed association between mutation frequency and gamma doses. This study will be useful for faba bean mutation breeding and may be applicable to other crops.