Genetic variability and character associations in vetiver (Vetiveria zizanioides L. Nash)

- Considerable genetic variability was noted among the forty collections of vetiver.
- Oil content and dry root yield were minimally influenced by environment factors.
- Highest direct contribution to total oil yield was made by fresh root and oil yield.
- Oil content and dry root yield were highly influenced by environment factors.
- Root yield, oil content, tillers and plant height may be used as a better selection criterion for improvement of oil yield.

Forty genetic stocks of vetiver (Vetiveria zizanioides L. Nash) were screened for high oil yield. The considerable amount of natural and genetic variability in morpho-metric traits was recorded. The estimate of heritability (^h2BS %) and corresponding genetic advance (GA), both were high for plant height (^h2BS % = 98.48 and GA = 64.83). Genetic (G) and phenotypic (P) associations coefficients among the seven traits indicated that plant height was highly and significantly correlated with tillers/plant (0.399**G, 0.389**P); fresh root with dry root yield (0.905**G, 0.769**P) and oil content with oil yield (0.397**G, 0.390**P) at both genotypic and phenotypic level. The plant height with root length was also positively correlated with each other at both genetic (G) and phenotypic (P) levels (0.282*G, 0.278*P). The path coefficient under study revealed that the highest direct contribution to total oil yield was made by fresh root yield (0.514) followed by oil content (0.386), tillers/plant (0.149) and root length (0.086) in percent.