Substrate–Genotype Interaction Influences Growth and Phytochemical Composition of Wild and Commercial Purslane (Portulaca oleracea L.) Microgreens

Purslane is highly suitable for intensive microgreen cultivation due to its rapid growth, high germination rate, and exceptional nutritional profile, including omega-3 fatty acids, essential vitamins, and minerals. While previous studies have mostly emphasized its basic composition, our research investigated additional functional traits, such as pigment accumulation and antioxidant activity. We also explored the cultivation potential of a wild purslane genotype (G2), naturally growing in the Botanical Garden of the Slovak University of Agriculture in Nitra, as a sustainable alternative to commercially available seeds (G1). This study examined how genotype and substrate interactions influence growth performance, pigment concentration, and antioxidant capacity in Portulaca oleracea microgreens. Both genotypes were grown on two different substrates: agar mixed with perlite and mineral wool. Although conserved DNA-derived polymorphism marker analysis revealed a high degree of genetic similarity between G1 and G2, significant phenotypic differences were observed. G1 exhibited greater fresh biomass and shoot length, making it more visually appealing for commercial microgreen production. In contrast, G2 showed higher dry matter content and enhanced accumulation of chlorophylls and carotenoids. Antioxidant activity, measured by DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), and FRAP (Ferric Reducing Antioxidant Power) assays, peaked in G1 cultivated on agar–perlite mix. These findings emphasize the importance of selecting the right genotype–substrate combination to optimize both quality and productivity in microgreen systems.