Morphology and SSR markers-based genetic diversity analysis of sesame varieties released in China

Abstract Background Sesame, one of the most important oil crops in the world, is rich in sesamol, sesamin, and other antioxidant substances, and can be consumed as oil, food, and vegetable. It has a high nutritional and economic value. To reveal the genetic diversity of the sesame varieties at the molecular and morphological levels, 25 pairs of simple sequence repeat (SSR) primers and 56 biological traits were applied to 101 Chinese sesame varieties released in recent decades, as well as 62 Chinese landraces and 20 alien accessions. Results The results indicated that a total of 166 SSR bands were detected, with an average of 6.64 per marker; the total alleles were 40.35, with an average of 1.614 per primer pair. Among them, the marker LG141 detected a maximum of 1.85 alleles, and SB393 had a minimum of 1.23 alleles. Shannon’s information index ranged from 0.2732 to 0.6497 with an average value of 0.5292; the polymorphic information index ranged from 0.0859 to 0.6357, with an average value of 0.5254, and the average heterozygosity (He) was 0.3246, suggesting that these sesame accessions have a narrow genetic diversity. The results of the unweighted pair-group method with arithmetic averaging (UPGMA) clustering were consistent with those of the binary principal component analysis, and the 183 sesame lines were categorized into three UPGMA groups. The genetic diversity coefficient of sesame germplasm is generally small, and the genetic relativeness is close. The genetic diversity coefficient of Chinese accessions is not much different from that of foreign resources. Moreover, a DNA fingerprint database of 183 sesame accessions including varieties and germplasm resources was constructed, and a corresponding two-dimensional code was developed. Conclusion The results of this study provide data reference for the breeding and promotion of new sesame varieties in China, the protection of new variety rights, the inquiry and identification of DNA genetic information of varieties, and the development and utilization of germplasm resources domestically and abroad.