DEVELOPMENT OF STARCH AND OTHER COMPONENTS IN NORMAL AND HIGH AMYLOSE BARLEY

The rate of synthesis of starch in the North American six‐rowed barley Glacier (C.I. 9676) was greater than that in the high amylose cultivar designated Glacier (Pentlandfield). In both cases most of the synthetic activity in the developing grain occurred between the third and sixth weeks after anthesis, but the total starch content of Glacier (Pentlandfield) was reduced by some 6% whilst its total production of protein and fats was greater. The ratio of amylose to amylopectin in the starch of both barleys increased during ripening of the grains, but the proportion of amylose in the mature starch of Glacier (Pentlandfield) attained a value of about 47%, compared with about 26% in Glacier (C.I. 9676). The average diameter of the starch granules in the high amylose barley was smaller than in normal barley at all stages of endosperm development. The two parental varieties and ten others closely related to Glacier were examined, but none possessed the high amylose characteristic. 1969 The Institute of Brewing & Distilling