WAAS-based stability analysis and identification of elite palmarosa (Cymbopogon martinii [Roxb.] Wats. var. motia Burk.) lines using multi-trait genotype-ideotype distance index for higher biomass and essential oil in the North-Western Himalayas

Palmarosa is an important aromatic perennial grass mainly cultivated for its high-value geraniol-rich essential oil. The growing global demand for palmarosa essential oil and the limited availability of suitable cultivars in the North-Western Himalayan region highlight the need of superior planting material crucial for its production. Hence, the present endeavour was led using 25 palmarosa genotypes evaluated for 12 traits to estimate the effects of genotype, environment and their interaction across four seasons (2019-23) using AMMI (additive main effects and multiplicative interaction) and BLUP (best linear unbiased prediction) based on WAAS (weighted average of absolute scores). Results from the study showed significant genotype x environment interaction effects for most of the traits evaluated. Essential oil characterization identified 6 major compounds with geraniol being the dominant constituent. Association studies showed its significant positive association with ocimene and myrcene while negative association with geranial, neral, L-linalool and (E)-caryophyllene. Higher variability estimates for tillers per plant, number of leaves per stem, flower head length, flower head branches, biological yield per plant and essential oil content demonstrated their potential utilization as selection criteria for higher genetic gains. Based on mean performance, AMMI, WAAS, and genotype and genotype by environment analysis, genotypes G1, G2 and G4 were identified as the most stable with high trait performance and geraniol content. Also, based on multi-trait genotype-ideotype distance index, genotypes were ranked as G2, G1, G4, G14 and G8. Hence, these genotypes can be prioritized to enhance geraniol-rich essential oil production and meet the growing demand for quality planting material.