<p>Drought is one of the major factors limiting potato productivity, particularly in environments with irregular rainfall and limited irrigation resources. Field-based selection for high-yielding potatoes under drought conditions is often restricted by high environmental variability, cost, and limited repeatability across seasons. Therefore, identifying reliable physiological and biochemical traits (secondary traits) measurable under controlled conditions that are associated with independent drought yield data is of practical importance for potato breeding. In this study, twenty-five potato genotypes with previously characterized 2-year field drought yield performance were evaluated at a pot experiment under nethouse control and drought conditions. Some physiological and biochemical traits were measured, and their relationships with independent field drought yield data were examined. Only traits significantly associated with field drought yield were considered for subsequent multivariate evaluation. Several gas exchange-, water-, osmotic adjustments-, and antioxidant enzyme activity-related traits measured under nethouse conditions showed significant associations with field drought yield. Multivariate classification indicated that traits expressed under both nethouse control and drought conditions were able to discriminate high-yielding genotypes under field drought conditions. Notably, a subset of traits measured under well-watered nethouse conditions showed strong association with field drought yield performance. These findings demonstrate that selected physiological and biochemical traits measured under nethouse conditions provide valuable information on field drought yield potential in potato, supporting the effectiveness of secondary trait-based approaches for early-stage prediction and selection of tuber yield potential in drought-prone environments.</p>