Breeding Bread-Making Wheat Varieties for Organic Farming Systems: The Need to Target Productivity, Robustness, Resource Use Efficiency and Grain Quality Traits.

Agronomic protocols (rotation, tillage, fertilization and crop protection) commonly used in organic and conventional crop production differ significantly and there is evidence that modern varieties developed for conventional high-input farming systems do not have the combination of traits required for optimum performance in organic farming systems. Specifically, there is evidence that prohibition on the use of water-soluble, mineral N, P and K fertilizers and synthetic pesticide inputs in organic farming results in a need to revise both breeding and selection protocols. For organic production systems, the focus needs to be on the following: (i) traits prioritized by organic farmers such as high nutrient use efficiency from organic fertilizer inputs, competitiveness against weeds, and pest and disease resistance, (ii) processing quality parameters defined by millers and bakers and (iii) nutritional quality parameters demanded by organic consumers. In this article, we review evidence from variety trials and factorial field experiments that (i) studied to what extent there is a need for organic farming focused breeding programs, (ii) investigated which traits/trait combinations should be targeted in these breeding programs and/or (iii) compared the performance of modern varieties developed for the conventional sector with traditional/older varieties favored by organic farmers and/or new varieties developed in organic farming focused breeding programs. Our review focuses on wheat because there have been organic and/or low-input farming focused wheat breeding programs for more than 20 years in Europe, which has allowed the performance of varieties/genotypes from organic/low-input and conventional farming focused breeding programs to be compared.

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 ~ 150 and ~ 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.