STRUCTURAL DIFFERENCES IN THE MATURE ENDOSPERMS OF GOOD AND POOR MALTING BARLEY CULTIVARS

Scanning electron microscopy (SEM) was used to examine a number of goo d and poor malting quality barley cultivars of both spring- and winter -sown type. Mature grains were frozen and fractured. and the endosperm surfaces were examined, with particular attention given to the sub-al eurone and starchy endosperm regions. All of the cultivars showed simi lar patterns of endosperm cell size, distribution and packing. However , variation in the patterns of fracture through the endosperm, and in the extent of starch-protein adhesion, were observed. Poor malting qua lity cultivars had fracture planes that traversed the starch granule-p rotein matrix interface, indicating a high degree of starch-protein as sociation similar to that exhibited by hard wheat cultivars. In contra st, good malting quality cultivars had fracture planes around the star ch granules, indicating a low degree of starch-protein binding similar to that exhibited by soft wheat cultivars. The possible role of starc h-protein binding in malting performance is discussed. (C) 1996 Academ ic Press Limited