Performance and Adaptation of Black Cumin (Nigella sativa L.) Genotypes under Natural Salinity Conditions in the Southwest Coastal Region of Bangladesh

Black cumin (Nigella sativa L.), a valuable medicinal crop, faces serious yield constraints under salinity stress, particularly in the coastal zones of Bangladesh. To identify genotypes with superior performance and adaptation to saline-prone regions, a two-year field experiment was conducted at the Agricultural Research Station, BARI, Satkhira, during the Rabi seasons of 2021–2022 and 2022–2023. Soil electrical conductivity (EC) ranged from 0.5–4.0 dS/m in 2021–2022 and 2.0–7.0 dS/m in 2022–2023, representing naturally varying field salinity conditions typical of the southwestern coastal region. Ten genotypes, including the check variety BARI Kalozira-1, were evaluated in a randomized complete block design with three replications. Significant genotypic differences (p < 0.01) were observed for most yield attributes. In both years, BC 012 and BC 014 exhibited superior growth and yield under saline conditions. BC 012 produced the highest number of seeds per capsule (98.67 and 77.42) and achieved yields of 0.98 and 0.53 t ha–1 in the two seasons, respectively. Genotypes BC 012 and BC 014 consistently showed superior performance across both seasons. Correlation analysis revealed that seed yield was strongly associated with plant height, number of capsules per plant, and 1000-seed weight. Multi trait genotype ideotype distance index (MGIDI) analysis ranked BC 012 and BC 014 as the top performers with stable performance across environments. These findings indicate the presence of substantial genetic variability for salinity tolerance in black cumin. BC 012 is a promising candidate for cultivation and future breeding programs aimed at enhancing salinity resilience in the coastal ecosystem of Bangladesh. It can be cultivated in the Satkhira region under saline conditions and fitted in with the new cropping pattern of this region during Rabi season.