Genetic Diversity Analysis of 11 Macrobrachium rosenbergii Germplasms Based on Microsatellite Markers

<i>Macrobrachium rosenbergii</i> is one of the largest and most economically significant freshwater prawns worldwide. Understanding its population genetic structure is essential for optimizing cross-breeding strategies, conserving germplasm resources, and supporting sustainable aquaculture. However, progress in this area has been hindered by the limited availability of reliable molecular markers. In this study, we developed 20 polymorphic microsatellite primer pairs and applied them to assess the genetic diversity of 11 populations collected from China and Southeast Asia (including Jiangsu, Zhejiang, Taiwan, Myanmar, Bangladesh, Sri Lanka, and Thailand). All loci exhibited high levels of polymorphism. The number of alleles (<i>Na</i>) ranged from 5 to 27, while the mean observed heterozygosity (<i>Ho</i>), expected heterozygosity (<i>He</i>), and polymorphism information content (<i>PIC</i>) were 0.570, 0.720, and 0.686, respectively. The genetic differentiation coefficient (<i>Fst</i>) among populations ranged from 0.017 to 0.289. UPGMA clustering revealed that the Myanmar population formed an independent branch, whereas the remaining ten populations clustered together, indicating relatively close genetic relationships among them. Beyond enriching the currently limited molecular marker resources for <i>M. rosenbergii</i>, this study provides essential baseline data for evaluating genetic diversity in existing populations and establishes a solid molecular foundation for future genetic monitoring and breeding programs.