*3.1. Plant Materials*

The 18 accessions studied (Table 1, Figure 1) were collected from the USDA and originated in Zambia. The leaves of the genotypes were harvested in August for each accession for the analysis of the functional compounds. The leaves were picked by hand from plants grown in three separate plots on the same plantation. The seeds were planted 20 cm apart in rows 60 cm apart in plots (3 × 4.2 m). Fertilizer (N:P:K 4:2:2 *w*/*w*/*w*) was applied at 550 kg/ha shortly after seeding. The experiment was conducted at the Korea Atomic Energy Research Institute (35◦30-33.9" N, 126◦50-02.3" E, Jeongeup, Korea). The plants' cultivation conditions between May and August 2017 were as follows: mean temperature 17.8–24.4 ◦C, relative humidity 66.0–80.9%, mean sunlight 10.4–7.0 h. All of these climate data were accessed through the Korea Meteorological Administration web portal (http://weather.go.kr/).
