Essential oil yield and composition of Tagetes minuta accessions from Argentina

Six wild Tagetes minuta accessions were collected from different locations in Argentina and were grown in the same environment to investigate their essential oil yield and composition. Essential oil yield differed among accessions. Essential oil production of Buenos Aires and Mendoza accessions did not change between years, and Mendoza always yielded more than Buenos Aires. There was no correlation between the yield of essential oil and the total aerial biomass. Regardless of the accessions origin, dihydrotagetone, alpha-phellandrene, limonene, o-cymene, as well as the isomers of beta-ocimene, tagetone and tagetenone were the major constituents of the essential oil. Three chemotypes were identified. Chemotypes differed in biomass production and essential oil yield of inflorescences and leaves. Leaves of the Mendoza accession were rich in dihydrotagetone as opposed to those of Buenos Aires, while the inflorescences of Mendoza accession, as well as the inflorescences and leaves of Buenos Aires have similar dihydrotagetone contents. (C) 2000 Elsevier Science Ltd. All rights reserved.