A simple antibody-based test for dough strenght. II, Genotype and environmental effects

Cereal Chem. 68(5):475-481 The ability of simple antibody-based tests to assess and predict specific and antibody binding were obtained with sets of varieties grown at different aspects of dough quality was evaluated using flours from several sets levels of nitrogen fertilization at the same site or in a range of environments. of wheat lines and varieties. Highest correlations between the binding The test was equally useful for analyzing a diverse range of unrelated of glutenin-specific antibodies and dough parameters were observed with genotypes and for examining progeny from related crosses. Finally, in dough strength (maximal resistance) and dough mixing (development time a set of wheats having similar high molecular weight glutenin subunits, and breakdown). Differentiation between stronger and weaker lines was differences in antibody binding were obtained that were highly correlated greatest when the sodium dodecyl sulfate (SDS)-insoluble protein fraction with differences in dough properties. was examined. Significant correlations between dough quality parameters The companion article (Skerritt 1991) describes the development of a simple test for prediction of dough strength by use of a monoclonal antibody-based enzyme-immunoassay. The assay used pairs of antibodies that bound well to particular high molecular weight glutenin subunits (HMW-GS) extracted from small wheat flour samples using a detergent, sodium dodecyl sulfate (SDS), and a reducing agent, dithiothreitol (DTT). Several factors, such as choice of antibody pairs, extractant, and assay conditions, were analyzed for their ability to distinguish between samples of a flour of a strong-dough variety, Cook, and similar flours from the variety Halberd, which produced doughs of intermediate strength. Using a set of 15 varieties of diverse quality, correlations were seen between antibody binding and a number of quality parameters including loaf volume, mixing time, and aspects of extensigraph behavior. However, interactions between antibody binding or other biochemical parameters and various dough properties found with a particular set of varieties or samples may not always be observed on examination of other sets of genotypes or analysis of grain grown under different environmental conditions. In the set of lines examined in the companion article (Skerritt 1991), protein content was relatively uniform (9-11%). Some positive correlations that were obtained between parameters such as extensibility and dough resistance may not be seen when, for example, material having less variation in dough quality is analyzed. For these reasons, it was important to study in detail the performance of the antibody method using a number of sets of flour samples differing in properties. Since protein content can affect dough properties and loaf volumes (Finney and Barmore 1948, Bushuk et al 1969), sets of the same varieties grown under different levels of nitrogen fertilization, parents and progeny of a specific cross grown at both a high- and a low-protein site, and a set of varieties chosen at random from a world collection grown at one site were included in this study. The effect of growth environment and protein content was first studied in a set of flour varieties grown at five sites with different climatic conditions, and then in a set of nine cultivars grown at 5-7 sites but blended to yield single flours of three different protein levels. A random set of lines from a breeding program was also analyzed. Finally, a set of wheats with identical HMW-GS compositions but differing in dough properties was examined to investigate whether antibody binding-quality correlations were maintained. These studies enabled choice of antibody combination and experimental conditions to be established that were suitable for analysis of a wide variety of bread wheats.