Edible Safety and Utilization Potential of Potato in Karst Areas with a High-Geological-Cadmium Background

Screening for cultivars with low Cd in edible organs but high Cd accumulation in non-edible organs represents a sustainable strategy for “producing while remediating”. However, the potential of potato cultivars to achieve this dual goal in high-geogenic-Cd karst areas remains unclear. A field experiment was performed to investigate biomass, Cd concentration, bioconcentration factor (BCF), translocation factor (TF) and Cd removal amount (R) in various organs of 26 potato cultivars, which were then classified into different Cd risk types. The results showed that in soils with 2.05–2.98 mg·kg−1 Cd, fresh tuber Cd concentrations ranged from 0.021 to 0.132 mg·kg−1, with nearly 90% of tubers complying with FAO/WHO and Chinese food safety standards. Cd levels in stems, leaves and roots were 1–2 orders of magnitude higher than in tubers, supporting potato as a suitable staple for safe production in such regions. BCF followed the order stem and leaf > root > tuber, while TF followed the order root to stem and leaf > stem and leaf to tuber. Tuber Cd was jointly controlled by Cd uptake, translocation and biomass dilution, with TFstem and leaf–tuber as a key predictor. Annual Cd removal by whole plants ranged from 1082.99 to 7283.64 mg·hm−2. Principal component analysis classified the cultivars into four types: edible-safe, safe remediation, risky remediation and high-risk types. Notably, cultivars V2, V6, V9, V13, and V18 had tuber Cd concentrations below 50% of the permissible limit, while V16, V8, and V25 achieved >5000 mg·hm−2 Cd removal without exceeding safety limits. These findings support the dual goal of safe potato production and in situ Cd remediation in high-background karst regions by selecting cultivars with low Cd accumulation in tubers but high Cd accumulation in non-edible organs.