THE EFFECT OF FERTILIZATION AND YEAR ON T HE BREAD WHEAT QUALITY

Wheat is the most widely growing cereal species all over the world. A major part of its production is assigned to human consumption. Therefo re, a great attention has been paid to bread-making quality of grain f or milling and baking processing in both monographs and world conferen ces. The main aim of the study was to evaluate bread-making quality pa rameters in a set of five Czech and Slovak model varieties under condi tions favourable for bread wheat production of high quality during a f ive-year period. Bread wheat varieties Ilona, Viginta, Hana, Sparta an d Samanta were grown in the sugar beet-growing region of Kromeriz in 1 990 to 1994. Agronomic practices were applied according to the standar d methodology; a course of split application of pure nutrients in diff erent years is illustrated in Figs 1. Bread-making quality was analyse d in the varieties investigated and data on individual parameters were processed using the STATGRAPHIC program. Average values of the qualit y parameters of tested varieties through five years are presented in F igs 2 to 11. An analysis of variance was used to determine effects of the variety and the year on individual quality parameters (Tab. I). A mean square ratio (Tab. I) suggests a dominant effect of the year on b ulk density, protein content and grain hardness. A correlation analysi s was used to find potential relationships among the parameters invest igated (Tab. II). The analysis revealed a number of statistically high ly significant correlations (P = 0.01 and 0.05) among bread-making qua lity parameters. A significant negative correlation was found between a falling number value and a degree of softening farinographs curve. T his finding is very important and confirms the legitimacy of introduci ng this method into the practice and necessity of using only wheats wi th minimum falling number of 200 s for milling and baking purposes. In this set, a positive correlation between protein content and simultan eously wet gluten content and nitrogen rates was found (Tab. III). How ever, it is necessary to note that besides nitrogen applied as pure nu trients, nitrogen from soil reserves affected protein synthesis in gra in. In that case, weather conditions, or rainfall, and potential water stress played an important role. Another factor affecting protein syn thesis and accumulation in grain is a transport of nitrogen nutrients through a stem. This fact is supported by a very highly positive, high ly significant correlation among rates of potassium nutrients and prot ein and wet gluten content in grain. The particular findings in this s tudy show, that technological quality of wheat is not a simple matter. Therefore, proper studies are necessary to determine all the factors which affect it.