Effect of irrigation, fertiliser type and variety on grain yield and nutritional quality of spelt wheat (Triticum spelta) grown under semi-arid conditions

Previous studies reported higher antioxidant and mineral micronutrient concentrations in organic compared to conventional wheat flour, but the reasons are poorly understood. Here we report results from a long-term, factorial field experiment designed to assess effects of variety choice, supplementary irrigation and contrasting fertilization regimes used in organic and conventional production on the nutritional quality and yield of spelt wheat grown in a semi-arid environment. Long-straw (Oberkulmer, Rubiota, ZOR) varieties had 10-40% higher grain Cu, Fe, Mn and Zn concentrations, while the modern, short straw variety Filderstolz had 15-38% higher grain antioxidant activity. Supplementary irrigation and the use of manure instead of mineral NPK as fertilizer had no substantial effect on the nutritional composition of spelt grain, but increased grain yields by similar to 150 and similar to 18% respectively. Overall, this suggests that breeding/variety selection is the most promising approach to improve the nutritional quality of spelt grain in semi-arid production environments.

Automated summary

Previous studies have shown that organic wheat flour has higher antioxidant and mineral micronutrient concentrations compared to conventional wheat flour, but the reasons for this are poorly understood. The long-term experiment discussed in this study found that variety choice, irrigation methods, and fertilization regimes had significant impacts on the nutritional quality and yield of spelt wheat grown in a semi-arid environment. Overall, breeding and variety selection were identified as the most promising approaches to enhance the nutritional quality of spelt grain in semi-arid production environments.