Effects of chitosan oligosaccharides on the yield components and production quality of different wheat cultivars (Triticum aestivum L.) in Northwest China

Chitosan oligosaccharides (COS) are the degradation product of chitosan, which has a potential application as a plant growth regulator. In contrast to previous studies that primarily examined COS effects under lab condition, this study was designed to provide detailed information about the effects of COS on wheat (Triticum aestivum L.) in large-scale field production. From 2011 to 2013 in Northwest China, seed dressing and foliar spraying at different growth stages with COS were applied to four wheat cultivars, which were divided into irrigated and rainfed varieties. The yield components and production quality of the COS treatments were measured. In the irrigated wheat cultivars, grains per spike from the COS seed dressing were significantly improved, and the spike number from COS spraying at tillering stage (Tf1) and returning-green (Tf2) stage increased significantly. COS impacted the grain yield significantly in all irrigated cultivars, whereas no significant COS effects on rainfed cultivar were observed. Improvements in spikelet sterility, plant height and the first internode length were detected in the COS treated cultivars. In COS spraying treatments, the flour rate and protein content exhibited a decreasing trend in irrigated cultivars, whereas a reduction of the gluten index and farinograph value were found in the rainfed cultivars. These results revealed that COS could affect the yield components and the production quality of wheat, and the various genotypes and application methods exhibited variations in the performance during the study.