Genetic Diversity Analysis of Sugar Beet Multigerm Germplasm Resources Based on SRAP Molecular Markers

This study utilized SRAP molecular markers to analyze the genetic basis of 106 multigerm sugar beet germplasm accessions. By revealing the genetic diversity, population structure, and differentiation patterns, it aimed to tap into the germplasm potential, guide core germplasm construction and hybrid combination optimization, and ultimately design a molecular breeding route to break through bottlenecks in sugar beet genetic breeding. In total, 24 core primer combinations were screened from 546 initial primer pairs for genomic DNA amplification. The results demonstrated that each primer combination amplified an average of five alleles. Genetic parameter calculations revealed moderate variation potential. Population structure analysis divided the germplasm into four genetic groups (G1–G4), highly consistent with cluster analysis and DAPC analysis results. Its reliability was jointly confirmed by STRUCTURE convergence verification (LnP(K) standard deviation) and cluster goodness-of-fit testing (r = 0.63166, p < 0.0001). Key findings indicated that Group G4 possesses a unique genetic background, and the maximum genetic distance exists between Group G1 and the other three groups, indicating its significant genetic differentiation characteristics. Gene exchange exists between the G3 and G4 populations. Genetic variation primarily originated from within populations (93%, FST = 0.1283). Genetic distances spanned from 0.385 (between accessions 66 and 71 within a group) to 0.836 (between accessions 47 and 85 across groups). Concurrently, gene flow analysis (Nm = 3.3977) indicated moderate genetic exchange among populations. This achievement established the first SRAP marker-based genetic architecture for multigerm sugar beet germplasm resources. It provides a quantitative population genetics basis for formulating targeted strategies for germplasm resource conservation and utilization, and lays the foundation for constructing an innovation system for sugar beet germplasm resources.