In the present study, we conducted a detailed analysis of the genetic diversity and structural organization of 96 domestic Korean rice varieties (Oryza sativa L.) using 2,565 high-resolution TCS-based single nucleotide polymorphism (SNP) markers. Genetic structural variations were investigated using diversity indices, PCA, genetic similarity, and network analysis. Genetic diversity analysis revealed a significant expansion of the genetic foundation after the 1980s, marked by a sharp increase in the number of alleles (Na) from the 2000s. Despite this, high genetic homogeneity was maintained, with an average similarity of 77.7%. The observed 10% difference among same-cross varieties suggests that critical genetic variations are fixed by strong selection pressures for quality traits. Network analysis (85% similarity threshold) confirmed that the Korean rice breeding population followed a distinct core-periphery model (eight communities). The connected 84 varieties had a centrality range of 0.01 0.39. Core Variety Groups (e.g., ‘Junam’ and ‘Sindongjin’) exhibited the highest centrality (up to 0.39), indicating their extensive use as key breeding parents and their function as the central axis of the genetic network. Bridge Variety Groups (e.g., ‘Hwayeong’ and ‘Samkwang’) played an intermediary role linking clusters. Crucially, 12 ‘isolated accessions’ showed zero centrality (0.00), representing a genetic disconnect from the main pool. This quantitative network-based assessment provides essential fundamental data for breeders to select appropriate germplasms. Furthermore, the findings suggest that the current cultivar naming system, which inadequately reflects genetic relationships, requires reassessment, and that the establishment of
objective
management standards based on this research is warranted.

Preserving and utilizing genetic diversity is crucial in crop breeding to address unpredictable situations such as climate change and evolving consumer demands. It serves as a source of new traits and alleles. Core collections are established from approximately 10-20% of conserved resources, and they are not only used for efficient management of genetic resources in seed banks but also applied in crop improvement programs and new gene discovery. These core collections demonstrate diversity based on the geographic origin of genetic resources and provide information on genetic similarity among resource types and collection regions. Recent advances in high-throughput genotyping has enabled high-resolution association mapping, allowing for the precise discovery of new genes and QTLs. The wheat genetic diversity and population structure of core collections are important in determining appropriate GWAS statistical methods for detecting these novel genes and QTLs. To maximize their utility, collecting detailed phenotypic data is crucial. This will expand their application in gene discovery, marker development, and more. In this study, we provided reviews for wheat core collection in the world to face the digital breeding era, where precise gene detection and manipulation are possible. The accumulation of genetic diversity, and phenotypic and genotypic information by core collections will contribute to breeding cycle acceleration and trait selection optimization.

Wheat (Triticum aestivum) is one of the three major food crops, along with rice and corn, and is the second most consumed crop after rice in Korea. However, the domestic production of wheat is insufficient, and the self-sufficiency rate is recorded in single digits. As wheat has a large genome size of 17 Gbp, and contains many repeated nucleotide sequences, it is difficult to conduct breeding studies and genome-based breeding lags behind that of other crops. To overcome the above challenges, we constructed a wheat core collection using simple sequence repeat markers that are suitable for the domestic cultivation environment with excellent reproducibility. Genetic diversity and population structure were analyzed using a core collection. Agricultural traits were evaluated in the Korean wheat core collection. Single marker analysis was correlated with 21 agricultural traits to identify potential molecular markers. These results may be useful for wheat breeding programs in the precision breeding era.

We collected 32 maize inbred lines from eastern cereal and oilseed research center in Canada to develop new maize varieties. We also evaluated genetic diversity, genetic relationships, and population structure using 35 SSR markers. A total of 269 alleles were revealed in 35 loci with an average of 7.69 and a range between 3 and 15 alleles per locus. The genetic diversity values varied from 0.176 to 0.889 with an average of 0.691. The polymorphic information content varied from 0.171 to 0.879 with an average of 0.659. Population structure analysis indicated that 32 Canadian maize inbred lines comprised four major groups and one admixed group based on a membership probability threshold of 0.80. The four major groups contained 13, 2, 5 and 2 maize inbred lines, respectively. From genetic relationships analysis, the all inbred lines were divided into three main groups at 26% genetic similarity. Group I included 22 inbred lines, and Group II included 9 inbred lines. Group III consist of only one inbred line. The results in this study would be useful for the improvement and development of new cultivars, planning crosses for hybrids or development of inbred line in maize breeding program

This study was conducted to compare the agricultural characteristics of total 444 common bean accessions from Korea (296), China (76), and El Salvador (72). Days to flowering were ranged from 41 to 83 days with an average of 61 days. Days to sowing to maturing were ranged from 86 to 143 days with an average of 104 days. Common beans from El Salvador tend to bloom and mature 3 to 7 days earlier than Korea and China accessions. In growth habit, over 50% of Korea and China accessions were indeterminate and climbing type, but 90.1% from El Salvador were Semi-determinate and climbing type. Qualitative traits were much different among three countries. Eighty-two percentage of immature pod colors were dark pink from El Salvador, but many of those were pale yellow from Korea (77.6%) and China (61.8%). Seed shapes were divided into four types of round, oval, cubic and kidney type, and the highest percentage of those were 30.4% with kidney type. The highest of those was 36.6% with oval type from Korea, 55.3% with kidney type from China and 79.2% with cubic type from El Salvador. Morphological characteristics of common bean from El Salvador were much different from those of Korea and China, which is necessary to collect more germplasm from its native and expand genetic diversity of common beans. Four hundred thirty-five common beans from Korea, China and El Salvador were analyzed using SSR markers. Ninety-two alleles were detected with a lowest of 6 at the BM161, BM181 and a highest of 18 at the BM154, BM160. The average polymorphism information content (PIC) was 0.72. To similar with population size among three countries, 292 Korean accessions divided four replications with 73 accessions. As a result genetic diversity was the highest of 0.73 in Chinese populations, while the lowest of 0.48 in El Salvador populations.