Wild rice (Oryza rufipogon) constitutes a primary gene source for rice breed improvement. Chromosome segment substitution line (CSSL) for O. rufipogon is a powerful tool for fine mapping of quantitative traits, new gene discovery, and marker-assisted breeding. Thus, they provide a basis for a wide range of genomic and genetic studies. In this study, a set of 198 CSSLs were developed from a cross between recurrent parent indica var. 9311 and an O. rufipogon donor parent; these were then genotyped using 313 polymorphic SSR markers evenly distributed across the 12 rice chromosomes. On average, each CSSL carried 2.16 introgressed segments, and the genetic distance of each segment was about 6 cM. The segments collectively covered 84.9 % of the wild rice genome. Based on these CSSLs, 25 QTLs involved in 10 agronomic traits were identified. Seven CSSLs were subjected to a whole-genome single nucleotide polymorphism chip assay and two QTLs, qSH4-1 and qDTH10-1, detected. In addition, a new QTL associated with the heading date was detected in a 78-Kb region on chromosome 10, thus proving the ability of these CSSLs to identify new QTLs and genes. The newly developed CSSL population proved a useful tool for both gene identification and whole-genome research of wild rice. These CSSL materials will provide a foundation for rice variety improvement.

The areca nut (Areca catechu L.) is a prominent tropical and subtropical crop of economic importance renowned for its significant medicinal value. It is recognized as one of the most prominent components of the four traditional Southern Chinese medicines. However, the lack of comprehensive genetic diversity data and reliable molecular markers has posed challenges in assessing and improving the areca nut germplasm for breeding programs. This study analyzed 196 areca nut materials, employing 40,173 high-quality single-nucleotide polymorphisms (SNPs) to evaluate the genetic relationships among the samples. Population structure analysis identified three distinct groups based on the optimal K-value, with the principal component analysis (PCA) results consistent with the results of population structure division. A phylogenetic tree constructed using the neighbor-joining method revealed clear separations among the samples based on their geographic origins. The nucleotide diversity (π) values ranged from 2.46 × 10⁻⁵ to 5.71 × 10⁻⁵, indicating limited genetic diversity within the areca nut population. The pairwise population differentiation index (Fst) revealed moderate genetic differentiation among the groups. The discovery of these SNPs will be helpful for areca nut conservation and utilization. The results of this study indicate the limited genetic diversity within areca nut germplasm resources, providing insights for management and breeding.