Assessment of the impact of growing conditions and of key crop-husbandry practices on arabinoxylan content in wheat flour

Most of the European population does not meet the dietary fibre (DF) intake of 25 g/day recommended by the European Food Safety Authority. Cereal-based products constitute the major DF source across European countries. Such products are often made from white wheat (Triticum aestivum L.) flour, where arabinoxylan (AX) accounts for about half of the total DF. To provide consumers with DF-enriched products, the present study assesses the feasibility of AX-targeted breeding by means of two sets of multi-environmental trials under Western-European conditions. One trial investigated the impact of growing conditions on the contents of total AX (TOT-AX) and water-extractable AX (WE-AX) in flour and their proportion (WE/TOT-AX), together with their relationships with hectolitre weight and milling quality, evaluated in terms of yields of flour, shorts, and bran. Broad-sense heritability (H²) of TOT-AX content and of WE/TOT-AX was estimated. A second trial investigated the effects of nitrogen fertilisation regime and sowing density. Significant differences in TOT-AX and WE-AX contents were observed between seasons, and, considering TOT-AX content, also between locations within seasons. Although only small differences in flour yield were observed, they were negatively correlated with higher TOT-AX content, WE-AX content, or WE/TOT-AX, independently of the growing conditions. Estimated H² of TOT-AX content and WE/TOT-AX were 33.7 % and 93.5 %, respectively. Nitrogen fertilisation regime and sowing density had no significant effects on TOT-AX and WE-AX contents and WE/TOT-AX. These results suggest that the AX content in flour can be selected by breeding. Nevertheless, there appears to be a trade-off with milling quality