Contact:
Dr Nikolaus Wellner
T: +44 (0)1603 255012
E: wellner@ifr.ac.uk

Endosperm cell walls in wheat grains

Genetic and environmental effects on processing and nutritional properties

Wheat is one of the three major cereal crops that dominate world agriculture. The major characteristics that influence the suitability of wheat grains for processing include grain size and homogeneity, fracture properties and starch, protein and non-starch polysaccharide content. All of these vary significantly, both among and within cultivars. One of the major factors contributing to the failure of new varieties is seasonal variability in these end-use qualities. Global warming is expected to result in even greater variation in weather patterns from year to year .

Bread-making wheat must meet stringent end-use quality criteria. Two bread-making wheat cultivars, Spark and Rialto, were selected to determine the impact of environmental conditions on the cell-wall composition of the starchy endosperm of the developing and mature grain, focussing on the period of grain filling (starting at about 14 days after anthesis). Studies carried out by Geraldine Toole over two successive seasons showed that the structure of the arabinoxylans in the endosperm cell walls changes from a highly-branched form (shown blue in the images) to a less-branched form (coloured green). Furthermore, during development the rate of restructuring was faster when the plants were grown at higher temperature with restricted water availability from 14 days after anthesis with differences in the rate of restructuring occurring between the two cultivars.