Achievement of higher biomass, yield and quality of essential oil of Tagetes minuta L. through optimizing the sowing method and seeding rate

Tagetes minuta L. is known as an industrial crop in the world as it possesses an essential oil that is extensively used in the perfumery and flavor industries. The crop performance is influenced by the planting/sowing method (SM) and seeding rate (SR); however, the effects of these variables on biomass yield and quality of the essential oil of T. minuta remain unclear. As a comparatively new crop, the responses of T. minuta to different SMs and SRs have not been studied in the mild temperate eco-region. Thus, the biomass and essential oil yield response of T. minuta (variety ‘Himgold’) to SM (line sowing and broadcasting) and SR (at 2, 3, 4, 5, and 6 kg ha−1) were investigated. The overall fresh biomass of T. minuta ranged from 16.86 to 28.13 Mg ha−1, while the essential oil concentration in fresh biomass varied from 0.23% to 0.33%. Irrespective of the SR, the broadcasting method produced significantly (p ≤ 0.05) higher fresh biomass yield by approximately 15.8% and 7.6% compared with line sowing during 2016 and 2017, respectively. An increase in biomass yield was noted as the SR increased up to 4 kg ha−1. The SR at 4 kg ha−1 registered approximately 41.9%–56.1% and 3.3%−10.3% higher biomass yield than the SR at 2 and 6 kg ha−1, respectively. No significant (p ≥ 0.05) differences in essential oil concentration in fresh biomass were observed due to the different SMs and SRs. Thus, T. minuta may be sown by the broadcasting method in the mild temperate eco-region with an SR of 4 kg ha−1.