*2.2. Cultivation of Curcuma longa*

The rhizomes of five turmeric varieties belonging to *C. longa* (CL3, CL5, CL9, CL10, and CL11) obtained from various sources (Table 1) were planted in seed germination trays filled with a soilless potting mix (Pro-Mix) on 3 April 2019. After planting, the trays were placed in a glass greenhouse at Alabama A&M University, Normal, AL (natural daylight increasing from 11 h in mid-March to about 14.5 h in early June; mean air temperature maintained at 26 ◦C) for 70 days for sprouting and plant development. The 10-weekold plants were then transplanted onto raised beds (60 cm wide, 15 cm high, 25 m long, 2 m apart, covered with black plastic mulch with drip irrigation tubing underneath the plastic) on 25 June 2019 at the Alabama A&M Winfred Thomas Agricultural Research Station located in Hazelgreen, AL (Latitude 34◦89- N and longitude 86◦56- W). Soil at the experimental site was a Decatur silt loam (fine, kaolinitic, thermic Rhodic Paleudult). The plants were grown using organic production methods and irrigation was provided as and when needed by the drip method. Prior to making the raised beds, the soil was plowed with a rototiller, and a mixture of composted cow manure, poultry litter, and vermicompost was incorporated into the soil at a rate equivalent to 45.5 kg of N/ha. Once the crop was established, a fish emulsion-based organic soluble fertilizer, Neptune's Harvest™ (Seven Springs Organic Farming and Gardening Supplies, Check, VA, USA), was applied through the irrigation system at 3-week intervals. Three plants from the middle of each row were harvested in mid-February 2020 by digging the plants, separating the rhizomes from the shoot, and washing clean of soil and debris with forced water jets. The mother and lateral rhizomes (Figure 1) were separated and placed in mesh trays and dried of excess water using fans at room temperature. The rhizomes were then placed in a cooler box with ice and carried to the chemistry department at the University of Alabama in Huntsville for oil extraction and profiling.

## *2.3. Essential Oils*

The fresh rhizomes, both mother and lateral rhizomes (Figure 1), were chopped and hydrodistilled for 4 h using a Likens–Nickerson apparatus with continuous extraction of the distillate with dichloromethane. Evaporation of the dichloromethane gave pale yellow to yellow rhizome essential oils (Table 1), which were stored at −20 ◦C until analysis.


**Table 1.** Hydrodistillation details for *Curcuma longa* rhizome essential oils cultivated in north Alabama.
