Genetic diversity and population structure analysis in Perilla frutescens from Northern areas of China based on simple sequence repeats.

In this study, 21 simple sequence repeat (SSR) markers were used to evaluate the genetic diversity and population structure among 77 Perilla accessions from high-latitude and middle-latitude areas of China. Ninety-five alleles were identified with an average of 4.52 alleles per locus. The average polymorphic information content (PIC) and genetic diversity values were 0.346 and 0.372, respectively. The level of genetic diversity and PIC value for cultivated accessions of Perilla frutescens var. frutescens from middle-latitude areas were higher than accessions from high-latitude areas. Based on the dendrogram of unweighted pair group method with arithmetic mean (UPGMA), all accessions were classified into four major groups with a genetic similarity of 46%. All accessions of the cultivated var. frutescens were discriminated from the cultivated P. frutescens var. crispa. Furthermore, most accessions of the cultivated var. frutescens collected in high-latitude and middle-latitude areas were distinguished depending on their geographical location. However, the geographical locations of several accessions of the cultivated var. frutescens have no relation with their positions in the UPGMA dendrogram and population structure. This result implies that the diffusion of accessions of the cultivated Perilla crop in the northern areas of China might be through multiple routes. On the population structure analysis, 77 Perilla accessions were divided into Group I, Group II, and an admixed group based on a membership probability threshold of 0.8. Finally, the findings in this study can provide useful theoretical knowledge for further study on the population structure and genetic diversity of Perilla and benefit for Perilla crop breeding and germplasm conservation.

Bulk segregant analysis (BSA) for improving cold stress resistance in maize using SSR markers.

In this study, eight inbred maize lines with high or low tolerance to cold temperature were investigated using bulk segregant analysis (BSA). Genetic diversity and genetic relationships were investigated using 100 simple sequence repeat (SSR) markers linked to cold tolerance in maize. A total of 319 alleles were identified. Among these, 128 were high coldtolerant-specific alleles and 61 were poorly coldtolerant-specific alleles, while the remaining 130 were shared between the two types. The number of alleles per locus ranged from 2 to 5, with an average of 3.19. The major allele frequency varied from 0.39 to 0.53 with an average of 0.47. The average gene diversity and polymorphic information content among all lines were 0.63 and 0.58, respectively. A dendrogram analysis identified three main clusters and most of the high tolerant inbred lines were clearly distinguished from the poorly tolerant inbred lines. In addition to the BSA, a total of 84 SSR markers were identified as high cold tolerance-specific alleles and 52 SSRs were detected as poorly cold tolerance-specific alleles. Of these, bnlg1273, umc1124, dupssr21, mmc0251, mmc0181, and phi041 have great potential for being molecular markers for cold tolerance in maize. Our results were in agreement with results previously reported for SSR markers linked with cold tolerance in maize. The identification and characterization of high and poorly cold tolerant maize lines based on SSR markers will be useful for future maize breeding studies.