Exploratory screening of faba bean germplasm for winter adaptation and seed quality in Northwestern Europe

Abstract Faba bean ( Vicia faba L.) is a high-protein legume suited to Northwestern Europe, yet adoption is hindered by limited winter survival, acute cold events, and seed anti-nutritional factors notably vicine and convicine (VC) that constrain food use despite high protein content. We conducted a two-year, two-season study in Belgium (2022–2024) directly comparing winter versus spring accessions via field phenotyping, intact-seed NIRS (n=343), and standardized breadmaking (10% wheat-flour substitution). Winter accessions experienced pronounced cold stress, exhibited slower photothermal growth, and nonetheless produced higher thousand-kernel weight, whereas spring accessions flowered more synchronously and gained height faster per unit thermal time. Culture and microscopy of symptomatic stems indicated that ≈75% of winter injuries were abiotic cold shock, not pathogen mediated. NIRS accurately predicted protein and VC, revealing exploitable diversity: white-flowered lines tended toward higher protein but elevated VC, while several coloured-flowered lines were low-VC, indicating a path to decouple food safety from protein gain. Multiple accessions achieved competitive loaf expansion (V/G ≈4.3) with acceptable crumb texture. These results define breeding priorities for Northwestern Europe: acute cold-shock tolerance with reliable winter hardiness, reduced VC at maintained protein, and validated flour functionality to enable field-to-fork deployment of faba bean.