Direct NIR spectral determination of genetic improvement, light availability, and their interaction effects on chemically selected yerba-mate leaves

•Decaffeinated and high caffeine yerba mate were selected based on their chemical profiles.•The selected plants were tested at five different shading levels simulating agroforestry conditions.•NIR and ASCA models determine conservation of chemical modification in leaves.•The chemical differences are maintained at any light level in chemically modified yerba mate.•The behaviors of decaffeinated and high-caffeinated yerba mate differed when subjected to the same light level.