Estimation of genetic variability, heritability and genetic advance as percent mean in black turmeric (<i>Curcuma caesia </i>Roxb.) genotypes

Genetic variability, heritability, and genetic advance were evaluated in 33 genotypes of black turmeric (Curcuma caesia Roxb.) to identify traits suitable for effective selection. Analysis of variance revealed highly significant differences among genotypes for all 45 growth, rhizome, and yield-related traits, indicating the presence of substantial genetic variability. Phenotypic coefficient of variation (PCV) was consistently higher than genotypic coefficient of variation (GCV) for all characters, with relatively narrow differences for most traits, suggesting limited environmental influence. High PCV and GCV were recorded for leaf lamina width (PCV: 24.53–24.54 %; GCV: 22.18%), petiole length (PCV: 30.10–30.28 %; GCV: 28.89–29.04 %), fresh rhizome yield per plant (PCV: 35.62 %; GCV: 24.92 %), fresh biomass per plant (PCV: 27.89 %; GCV: 22.48 %), and several rhizome traits. Broad-sense heritability ranged from moderate to high (49.00–95.00 %), with high heritability coupled with high genetic advance as percent of mean observed for leaf lamina width (h²: 82.00 %; GAM: 41.27–41.30 %), petiole length (h²: 92.00 %; GAM: 24.89–25.22 %), fresh biomass (h²: 65.00 %; GAM: 37.31 %), primary rhizome length (h²: 86.00 %; GAM: 38.16 %), and projected fresh rhizome yield (h²: 85.00 %; GAM: 59.54 %). Fresh rhizome yield per plant varied widely from 227.01 to 654.87 g, indicating ample scope for selection. The predominance of additive gene action for these traits suggests that direct phenotypic selection would be effective. Overall, leaf lamina width, petiole length, biomass components, rhizome characters, and fresh rhizome yield emerged as reliable selection indices for yield improvement, conservation and genetic enhancement of black turmeric.