**Background:** EU organic farming standards prohibit synthetic mineral nitrogen fertilizers and most synthetic pesticides, relying instead on organic fertilizers (manure, compost, legume leys) and non-chemical crop protection. This creates fundamentally different growing conditions compared to conventional high-input systems. Nitrogen availability is lower and less predictable in organic systems, and disease/weed profiles differ. Consequently, wheat varieties bred for conventional systems may lack essential traits for optimal performance under organic management. This review synthesizes evidence from factorial field experiments and variety trials to assess whether organic-focused breeding programs deliver varieties better suited to organic systems, particularly for bread-making quality and nutritional composition.
**Methods:** The authors review results from long-term factorial field experiments in Northern Europe (UK) and Southern Europe (Crete, Greece) comparing winter and spring wheat varieties from organic breeding programs (OBP) and conventional breeding programs (CBP) under contrasting fertilization regimes (cattle manure vs. mineral N), crop protection protocols (organic vs. conventional), and input levels. They also re-analyze data from multi-site spring wheat variety trials conducted on organic farms in three contrasting UK pedo-climatic zones (Norfolk, Northumberland, Berkshire). Key outcomes assessed include grain yield, protein concentration, Septoria and yellow rust severity, lodging, leaf and grain phenolic concentrations, mineral micronutrient (Fe, Zn, Ca) and toxic metal (Cd) concentrations, and bread-making quality parameters.
**Key Results:** In UK winter wheat trials, the OBP variety Aszita and the CBP variety Solstice produced the same grain yield (2.9 t/ha) under cattle manure fertilization, but Solstice significantly outyielded Aszita under mineral N (4.7 vs. 3.7 t/ha). Aszita had significantly higher grain protein concentration across all fertilization regimes (e.g., 13.7% vs. 10.6% with mineral N at 170 kg N/ha), lower Septoria severity on flag leaves (168 vs. 276 AUDPC), and higher leaf phenolic acid (16.2 vs. 12.3 mg/g) and flavonoid (14.3 vs. 10.2 mg/g) concentrations. Lodging was only observed in Aszita, but was low under manure fertilization (2–5%) and increased under mineral N without growth regulators (23%). Significant three-way interactions (fertilizer type × input level × variety) were found for Septoria severity and grain protein. In multi-site spring wheat trials, very highly significant (p < 0.001) site × variety interactions were detected for grain yield, disease severity, protein content, and mineral concentrations. For example, grain yield ranged from 1.6 t/ha (Zebra at Sheepdrove) to 5.6 t/ha (Tybalt at Courtyard). Grain protein content ranged from 10.6% (Monsun at Courtyard) to 15.2% (Zebra at Sheepdrove). Grain Cd concentrations varied significantly by variety (e.g., 36–50 µg/kg) and site (35–44 µg/kg). Grain Zn ranged from 24 mg/kg (several varieties at Courtyard) to 48 mg/kg (Zebra at Sheepdrove). Correlation analyses showed negative associations between grain yield and both Fe and Zn concentrations, and between grain yield and protein content. In spelt wheat trials across the UK, Czech Republic, and Greece, significant variety × environment interactions were found; the OBP variety ZOR produced the highest yields under semi-arid conditions in Crete, while the short-straw conventional variety Filderstolz yielded highest in the Czech Republic.
**Clinical Implications:** The findings have direct implications for human nutrition and food safety. Organic wheat products, particularly from OBP varieties and older longer-straw varieties, tend to have higher concentrations of nutritionally desirable phenolic antioxidants and mineral micronutrients (Fe, Zn, Ca), and lower concentrations of the toxic metal Cd, especially when grown under organic fertilization. The higher phenolic content is linked to both lower N availability (which upregulates phenolic biosynthesis) and selection for disease resistance in organic breeding programs. The higher mineral micronutrient content may be associated with longer straw length, which correlates with better mycorrhizal associations and micronutrient uptake. However, the use of OBP varieties under conventional high-N fertilization can increase grain Cd concentrations (e.g., Aszita: 16.3 µg/kg with mineral N vs. 9.9 µg/kg with manure), highlighting the importance of matching variety to production system. The review also notes that wholegrain flour retains 2–5 times higher antioxidant and mineral levels than white flour, and that organic consumers show greater demand for wholegrain and sourdough products. The authors call for breeding programs to incorporate nutritional quality traits and for development of baking protocols suited to lower-protein flours, given the negative correlation between N inputs and phenolic/antioxidant content and between grain yield and protein content.