Construction of Soybean Mutant Diversity Pool (MDP) Lines and an Analysis of Their Genetic Relationships and Associations Using TRAP Markers

Mutation breeding is useful for improving agronomic characteristics of various crops. In this study, we conducted a genetic diversity and association analysis of soybean mutants to assess elite mutant lines. On the basis of phenotypic traits, we chose 208 soybean mutants as a mutant diversity pool (MDP). We then investigated the genetic diversity and inter-relationships of these MDP lines using target region amplification polymorphism (TRAP) markers. Among the different TRAP primer combinations, polymorphism levels and polymorphism information content (PIC) values averaged 59.71% and 0.15, respectively. Dendrogram and population structure analyses divided the MDP lines into four major groups. According to an analysis of molecular variance (AMOVA), the percentage of inter-population variation among mutants was 11.320 (20.6%), whereas mutant intra-population variation ranged from 0.231 (0.4%) to 14.324 (26.1%). Overall, intra-population genetic similarity was higher than that of inter-populations. In an analysis of the association between TRAP markers and agronomic traits using three different statistical approaches based on the single factor analysis (SFA), the Q general linear model (GLM), and the mixed linear model (Q+K MLM), we detected six significant marker-trait associations involving five phenotypic traits. Our results suggest that the MDP has great potential for soybean genetic resources and that TRAP markers are useful for the selection of soybean mutants for soybean mutation breeding.