Black cumin (Nigella sativa L.), a widely used medicinal and aromatic plant, has gained significant attention due to its diverse applications in the drug and food manufacturing. The current study assessed the genetic variation and agronomic performance of twenty-seven black cumin genotypes originating from various regions of Iran, focusing on a range of morphological traits and yield components. The genotypes were grown under controlled greenhouse conditions in a randomized complete block design with four replicates. Some traits, including plant height, flowering stem length, seed yield, capsule weight, and thousand-seed weight, were measured for each genotype. Statistical analysis revealed high genetic variation across most traits, with the coefficient of variation (CV) exceeding 20% for many characters, indicating significant potential for selection in breeding programs. The high variations of seed yield, seeds per capsule, and seed size suggested that these traits could be targeted for improvement in future breeding efforts. Agglomerative hierarchical cluster analysis was performed using standardized squared Euclidean distances to group the genotypes based on their genetic similarity. The resulting dendrogram identified four distinct clusters, with Cluster-A containing genotypes (G21, G23, G24, and G26) exhibiting the highest seed yield and overall favorable agronomic traits, making them prime candidates for breeding programs focused on high yield. Cluster-B included genotypes with large seed size and thousand-seed weight but lower overall yield performance. Cluster-C genotypes displayed a balance of high seed yield, seed size, and other yield components. Although Cluster-D performing poorly in terms of seed yield, contained genotypes with large seed size, which could be valuable for market-oriented breeding. The cluster analysis groups black cumin genotypes based on similarities in traits, such as seed size, oil content, or disease resistance, helping identify distinct genetic clusters. This information enables researchers and farmers to select superior genotypes from diverse clusters for breeding programs, ensuring the combination of complementary traits to improve crop yield, enhance stress tolerance, and increase overall productivity. However, four genotypes including Kashmar, Mashhad-I, Mashhad-II, and Miandoab, are recommended for cultivation through farmers and entering in breeding programs due to their high seed yield performance.
