Balla K., Rakszegi M., Li Z., Békés F., Bencze S., Veisz O. (2011): Quality of winter wheat in relation to heat and drought shock after anthesis. Czech J. Food Sci., 29: 117-128.Raw material quality, which is influenced not only by the protein content, insoluble protein polymers, and gluteninto-gliadin ratio but also by the starch granule size, is very important for the quality of bakery products. This study investigated the effect of high temperature and drought (during grain-filling) on the quality and components yield of five winter wheat varieties. Drought and drought + heat were found to have a much greater influence on the yield and quality than heat stress alone. Averaged over the varieties, the yield losses were 57% after drought, 76% after drought + heat, and only 31% after heat stresses. The reductions in the unextractable polymeric protein fraction and glutenin-to-gliadin ratio indicated a poorer grain yield quality, despite the higher protein content. Quality deterioration was observed after drought or drought + heat, while high temperatures alone resulted in no change or in a better ratio of protein components. A significant negative correlation was observed between starch granule size and relative protein content after drought, demonstrating that this parameter contributes, together with protein, to the baking quality of the flour. Wheat varieties with satisfactory genetic traits are essential for the production of high quality wheat. Certain quality parameters vary over a very wide range in individual breeding lines. This broad genetic variability is demonstrated by the fact that the protein content ranges from 10-17%, the gluten content from 20-45%, the grain hardness from 10-85, the falling number from 60-450, and the farinograph index from C2 to A1. These differences in quality also depend on the soil, nutrient supplies, standard of plant protection, and other agronomic factors. The weather conditions during the growing season, especially the rainfall quantity and temperature, have a substantial influence on the plant metabolic processes, and thus on wheat quality.
