Constructing DNA Fingerprinting and Evaluating Genetic Diversity Among Sugar Beet (Beta vulgaris L.) Varieties Based on Four Molecular Markers

The authentication of sugar beet varieties necessitates a comprehensive and efficient analysis of the genetic diversity, which mandates the utilization of a collection of molecular markers. This study aimed to assess the genetic variation and genetic structure of 111 sugar beet varieties by utilizing with simple sequence repeat (SSR), restriction site amplified polymorphism (RSAP), direct amplification of minisatellite DNA by PCR (DAMD), and start codon targeted (SCoT) molecular markers. Moreover, a DNA fingerprinting technique was adopted to construct a reliable identification system. The results revealed a considerable variation in the average number of alleles among the four molecular markers: 11.3 (SSR), 12.83 (RSAP), 26.5 (DAMD), and 32 (SCoT). Notably, the SCoT marker exhibited the highest average polymorphic bands. The utilization of both single marker data and combined data in conjunction with the neighbor-joining clustering and population structure analyses unveiled that the combined data provided more accurate assignment of individual varieties to predetermined populations compared to individual marker data alone. These clustering results were consistent with the breeding institution and origin of the varieties. When the combined data were employed, both methods consistently classified the 111 sugar beet varieties into five distinct taxa, highlighting highly consistent clustering results. Notably, Nei’s genetic distance ranged from 0.111 to 0.402, with an average of 0.275, indicating a close relationship and narrow genetic diversity among the sugar beet varieties. DAMD and SCoT markers demonstrated higher values of polymorphism information content (PIC) and discriminating power ( D ) compared to the SSR and RSAP markers. Therefore, DNA fingerprinting of the 111 sugar beet varieties was constructed using the 50 polymorphic loci derived from the URP6R and SCoT13 primers, which demonstrated the highest PIC and D values. This establishment enables rapid identification of the authenticity of sugar beet varieties and serves as a foundation for the subsequent establishment of an electronic ID data information platform dedicated to sugar beet varieties. These results provided implications for the future efforts in authenticity identification and breeding of sugar beet varieties.