Genetic variation and association mapping in the F2 population of the Perilla crop (Perilla frutescens L.) using new developed Perilla SSR markers

The transcriptome sequencing approach RNA-seq represents a powerful tool for transcriptional analysis and development of simple sequence repeat (SSR) markers for nonmodel crop. In the Perilla crop, analysis of the distribution of different repeat motifs showed that the most abundant type was dinucleotide repeats (62.0%), followed by trinucleotide repeats (35.3%), with the two together comprising 97.3% of the eSSR repeats. In this study, we developed 39 new SSR primer sets by the transcriptome sequencing approach RNA-sEq. In total, 130 alleles were detected segregating in nine Perilla accessions with an average of 3.3 alleles per locus, ranging from 125 to 360 bp. The number of alleles per locus ranged from two to six. To detect SSR markers associated with morphological characteristics of Perilla crop, 40 individuals from an F-2 population of Perilla were selected for association analysis based on their leaf- and plant-related characteristics. An association analysis of 37 SSR markers and 9 leaf- and plant-related traits in the 40 individuals of the F-2 population was conducted. From the analysis, we identified 12 SSR markers associated with leaf-related traits and 11 SSR markers associated with plant-related traits. Therefore, the new Perilla SSR primers described in this study could be helpful in identifying genetic diversity and genetic mapping, designating important genes/QTLs for Perilla crop breeding programs, and allowing Perilla breeders to improve leaf and plant quality through marker-assisted selection (MAS) breeding programs.