Microsatellite-Based Genetic Diversity, Population Structure and Bottleneck Analysis in Peanut: Conservation and Utilization Implications

Collecting, conserving, and using peanut germplasm depends on our ability to comprehend genetic variability in gene banks. The peanut genetic resources are not well characterized for their conservation and potential future use. Increased use of exotic and interspecific derivatives is required to reduce the yield gap, identify new alleles, and introduce them. We assessed the genetic diversity and organization of an 83-germplasm peanut population. Ninety polymorphic markers generated 326 alleles, and the similarity matrix formed three main clusters. Polymorphism information content (PIC) ranged from 0.09 to 0.85, indicating greater genetic diversity in these genotypes. Germplasm from exotic collections had the highest levels of diversity, followed by released cultivars, and interspecific derivatives had the lowest levels of diversity. The number of private alleles in interspecific derivatives, exotic collections, and cultivars was 1, 6, and 3, respectively. Overall, several SSRs showed a high probability of null alleles. In addition, gene diversity and allelic richness were 0.526 and 3.18, respectively. Analysis of molecular variance revealed variation both within and between individuals. Principal coordinate analysis and population structure analysis subdivided all germplasm lines into three populations. Bottleneck analysis revealed that all three populations experienced genetic bottlenecks, as a shifted mode was observed. This paper highlights the importance of using microsatellite markers to study the diversity of interspecific derivatives, including recently developed ones, and create effective conservation programs.