1) Continuing the study of the chemical composition of the epigeal part of Korolkowia sewerzowii, solanidine and diacetylsevedine were isolated by chromatographic separation, which is the first time these two alkaloids have been obtained from this plant. 2) The dependence of the chemical composition of maize grain on genotype was investigated using initial (+/+), opaque-2 (o2/o2), and double mutant (o2/o2, Su2/Su2) forms. The contents of protein, fat, starch, and cellulose were determined by near-infrared reflection spectroscopy. The results showed that the grain of the double mutants had a more balanced chemical composition compared to the opaque forms, and the index of biological value (ratio of total carbohydrate components to total protein and fat) was at the same level as that of the initial analogs, indicating an improved nutritional value with a better endosperm structure due to the combination of o2 and Su2 mutations.