ORIGINAL PAPER Open field inoculation with PGPR as a strategy to manage fertilization of ancient Triticum genotypes Giancarlo Pagnani 1 & Angelica Galieni 2 & Fabio Stagnari 1 & Marika Pellegrini 3 & Maddalena Del Gallo 3 & Michele Pisante 1 Received: 30 July 2019 /Revised: 24 September 2019 /Accepted: 26 September 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract Ancient wheats are characterized by high nutritional value, low nitrogen requirements, and good adaptability which make them particularly suitable for marginal areas or low-input agricultural systems. Among environmental-friendly fertilizers, plant growth- promoting rhizobacteria represent a promising tool thanks to their ability to colonize soil and plant roots. In this study, a consortium of plant growth-promoting rhizobacteria was applied on three ancient wheat varieties (durum wheat: Senatore Cappelli, Saragolla; emmer: Molisano). Colonization and survival of bacteria in wheat seedling roots were investigated on in vitro cultures. The effects of the bacteria on crop growth, yield, and grain protein accumulation were studied in a 2-year open field experiment (split-plot arranged on a randomized block). Three different fertilization strategies were compared: (i) one bacterial application at sowing, (ii) two bacterial applications at sowing and tillering stages, (iii) zero bacterial application. Scanning electron microscope imaging revealed the ability of the bacteria to colonize effectively seedling roots thanks to biofilm formation on root surfaces. In both years, double bacterial application positively affected plant physiology, growth, and yield. Plants with double bacterial application showed highest physiological traits, and resulting enhanced yield and grain protein contents. The applied bacterial consortium positively performs on ancient wheats, even if the magnitude of its success depends on timing and rate of application. Keywords Ancient wheat . PGPR . Bio-fertilization . Wheat quality . SEM Introduction Species belonging to Triticum genus, generally designated as wheat, are one of the most important energy commodities of human diet as well as a valid resource for non-food and in- dustrial applications (Boukid et al. 2018). During the last decades some species, termed as “ancient wheats”, have gained increasing consideration thanks to their high nutritional values, bioactive compound accumulation (Cooper 2015; Dinelli et al. 2009), positive health implications (Dinu et al. 2018; Dixit et al. 2011), and higher diversity of rhizosphere bacterial community than modern cultivars (Germida and Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00374-019-01407-1) contains supplementary material, which is available to authorized users. * Fabio Stagnari fstagnari@unite.it Giancarlo Pagnani gpagnani@unite.it Angelica Galieni angelica.galieni@crea.gov.it Marika Pellegrini marika.pellegrini@guest.univaq.it Maddalena Del Gallo maddalena.delgallo@univaq.it Michele Pisante mpisante@unite.it 1 Faculty of Bioscience and Technologies for Food, Agriculture and Environment, University of Teramo, Campus Universitario di Coste Sant’Agostino, via R. Balzarini 1-, 64100 Teramo, TE, Italy 2 Council for Agricultural Research and Economics, Research Centre for Vegetable and Ornamental Crops, Italy, Via Salaria 1, 63077 Monsampolo del Tronto, AP, Italy 3 Department of Life, Health and Environmental Sciences, University of L ’Aquila, Via Vetoio, Coppito 1, 67100 L ’Aquila, Italy Biology and Fertility of Soils https://doi.org/10.1007/s00374-019-01407-1