Potential of Tagetes minuta L. populations as a high-yield crop for essential oil production in Garhwal Himalaya, India

Abstract Although a weed in many parts of the world, Tagetes minuta L. has become a crop of commercial importance. The current study assessed the morphological variation and oil yield of T. minuta from various populations in the Garhwal, Himalayan region, aiming to identify those with high yields. Results revealed that the qualitative morphological features of T. minuta populations were consistent across all samples, suggesting a uniform genetic makeup. However significant ( p ≤ 0.05) variation was detected in quantitative morphological traits among the populations. With Barsu exhibiting the tallest plants and Gangnani showing the greatest leaf length and number of leaflets per leaf. The Barsu population also demonstrated superior biomass and essential oil yields at both pre- and full-flowering stage. At the full-flowering stage, fresh biomass, essential oil content, and yield were 7.48%, 52.04%, and 55.16% higher, respectively, compared to the pre-flowering stage. However, stem biomass at the full-flowering stage decreased by 8.25% relative to the pre-flowering stage. Strong positive correlations were revealed between plant height, biomass, and oil yield, with taller plants showing higher productivity. Geographical variables, such as latitude and longitude, influenced various morphological and yield traits, particularly highlighting increased values towards higher latitudes and more eastern regions. Additionally, phenotypic and genotypic analyses underscored high variation in traits such as the number of main branches and biomass yield, with heritability estimates suggesting potential for targeted breeding. The highest genetic gain was observed for the number of primary branches and stem biomass, indicating opportunities for future improvements in essential oil production. This study highlights the potential of T. minuta for essential oil production and emphasizing the importance of both genetic and environmental factors in yield variation.