A comparative study of organic and conventional management on the rhizosphere microbiome, growth and grain quality traits of Tritordeum

Tritordeum is a novel hexaploid cereal derived from the cross between a wild Chilean barley species (Hordeum chilense Roem. et Schultz) and durum wheat (Triticum turgidum ssp. durum Desf.) that is potentially of great interest for human nutrition. In this study, a commercial and an experimental Tritordeum cultivar were analyzed in comparison with a reference durum wheat under conventional and organic management. We demonstrate that Tritordeum is better adapted to organic farming through an increase in the below-ground rhizosphere community of the Bacteroidetes phylum, which includes many bacteria species known to exert beneficial effects on plants, particularly for root growth. Despite a considerably lower grain yield, Tritordeum had better quality traits than durum wheat, particularly under organic farming vs. conventional management, with respect to total protein contents, high molecular weight glutenin subunits, antioxidant free phenols and nutrients (i.e., calcium, potassium, sulphur, iron, and zinc), depending on the cultivar. We conclude that Tritordeum is a promising cereal in light of its quality traits and adaptability to sustainable crop management practices, such as organic farming, although further improvement in yield potential should be pursued by breeding and by optimising the cultivation method.