Performance of Modern and Traditional Spelt Wheat (Triticum spelta) Varieties in Rain-Fed and Irrigated, Organic and Conventional Production Systems in a Semi-Arid Environment; Results from Exploratory Field Experiments in Crete, Greece

Background: Consumer demand for organic spelt wheat has increased rapidly and production has expanded into semi-arid regions, where it was not traditionally grown. Methods: Here, we report the results of a factorial field experiment designed to compare the performance of four spelt varieties grown in rain-fed and irrigated, conventional and organic production systems in a semi-arid environment. Results: Irrigation resulted in 2.5-fold higher grain yields, a reduction in grain protein, taller plants and an increase in stem lodging. While yields of all varieties were similar and low in rain-fed production, the variety Zuricher Oberlander Rotkorn (ZOR) produced the highest, Filderstolz and Oberkulmer intermediate and the variety Rubiota the lowest grain yields in irrigated systems. Organic production with chicken or sheep manure as fertilizer resulted in 15% higher yields that mineral NPK fertilizer-based conventional production protocols. Conclusions: Rain-fed spelt production results in very low yields and is therefore unlikely to be commercially viable. Results suggest that organic fertilization regimes and the variety ZOR will result in the highest yields in irrigated systems, while the two traditional spelt varieties Filderstolz and Oberkulmer will more reliably produce grain protein levels that comply with bread-making quality standards.