Nigella sativa L. belongs to family Ranunculaceae, commonly known as Kalonji, is mainly a seed spice crop. Ajmer Nigella-1 (AN-1) and Ajmer Nigella-20 (AN-20) varieties of Nigella sativa L. were investigated for this study to estimate the possible genetic variations and their associations between them. Data was collected on various growth and morphological traits at 50 days after sowing (DAS), 100 DAS and at maturity. Data were normally distributed as suggested by S-W and K-S normality test. Descriptive statistics indicated higher mean value for the traits; total plant height (Mean ± SE) followed by shoot length (Mean ± SE) and number of seeds per capsule (Mean ± SE) respectively. Analysis of variance measured the significant differences and genetic variability among the means of traits at p ≤ 0.05 and 0.01. The regression plot suggested goodness of fit among the data with expected variability through higher value of R2 (COD). Pearson’s correlation showed positive and highly significant association among all the traits at p ≤ 0.01 suggested any improvement for the traits will directly affect with slight increment in the trait, seed yield per plant. Principle component analysis extracted 3 components with Eigen value more than 1 and contributed approximately 99.74% of total variation present among the traits. Phenotypic variance was estimated higher than both genotypic and environmental variation indicated the expression of AN1 and AN20 genetic makeup for phenotype and morphology. Although phenotypic, genotypic and environmental variance was estimated higher values for the traits, number of seeds per capsule and dry weight. High and moderate heritability (broad sense) for the growth (total plant height, shoot length and root length) and reproductive (number of capsules, number of flowers, seed yield per capsule and seed yield per plant) traits suggested that AN1 and AN20 are high yielding varieties. High heritability coupled with high genetic advance over mean was estimated for the reproductive traits (number of capsules, number of flowers, seed yield per capsule and seed yield per plant) suggested the potential opportunity for the improvement of these traits for higher yield. A small difference was observed between phenotypic and genotypic coefficient of variation suggested the presence of considerable genetic base for improvement and stability of the traits. The value of critical difference at p ≤ 0.05 was estimated higher for the growth traits, total plant height followed by shoot length respectively suggested the stability of the traits in given environmental conditions. Over all 2 growth stage traits, total plant height and shoot length and 4 reproductive stage traits, number of capsules, number of flowers, seed yield per capsule and seed yield per plant showed potential for further improvement in plant breeding programs.
