A two-way analysis of variance (ANOVA) showed that differences among the 462 accessions for GT, GC and AC were highly significant ( P < 0.01), indicating that there were a large amount of genetic variation in the natural population.
Analysis of variance for the GT, GC and AC traits in the population containing the 462 accessions from 2011-2013 at the Nanjing site indicated extremely significant effects due to the genotype, year, year × genotype, and replications within year for the GC and AC traits, but nonsignificant effects due to the replications within year on GT (0.83) (Additional file 4 : Table S3).