Phenotyping of the nickel metal crop Bornmuellera emarginata for establishing breeding selection criteria

Nickel is a crucial metal widely used in various industrial applications, such as lithium‐ion batteries and stainless‐steel production. The increasing demand for nickel and resource depletion challenges highlight the need for sustainable extraction methods. Agromining employs hyperaccumulator plants to extract nickel from soils that are either contaminated or naturally enriched in nickel. Bornmuellera emarginata is a nickel hyperaccumulator originating from Greece and a promising candidate for nickel agromining. This study aimed to identify suitable genotypes for a successful “domestication” breeding program, focusing on phenotypic traits. Seeds from 35 plants across six wild populations were cultivated under controlled conditions for 7 months to complete a full life cycle. In this period, growth parameters (e.g., plant height (PH), leaf size, and biomass) were determined. Geographically proximate populations displayed greater phenotypic similarity than those from distant locations. Substantial morphological variations, including PH (40–126 cm) and leaf length (6–13 cm), were observed. Nickel concentrations in plants ranged from 290 to 6250 mg kg−1 dry weight, resulting in nickel yields of 10–145 mg/plant. The notable phenotypic differences among genotypes provide a valuable biological resource for initiating a breeding program to enhance overall nickel yield in B. emarginata agromining crops. Selection and breeding efforts should prioritize genotypes with high biomass production and nickel concentrations. This research lays the foundation for targeted breeding to optimize the potential of B. emarginata in nickel agromining.