| Abstract: | Distribution of starch components of maize (Zea mays L.) and their properties were investigated by gel filtration after debranching and by exhaustive hydrolysis of starch-granules with glucoamylase. Based on the results, relationship between genotypes and properties of starch components were discussed. The sugary-1 (su1), sugary-2 (su2), and dull (du) mutants produced high amylose maize, while amylopectin of su2 was normal type and those of su1 and du were novel type. In the double-mutant combinations, the waxy (wx) gene decreased amylose content. Starches of du su1 or du su2 possessed greatest amount of amylose among starches examined. Contents of amylose, intermediate fraction (Fr.) and longer branches of amylopectin increased in most cases when the amylose-extender (ae) gene was introduced. Starches of ae possessed longer average chain-lengths of amylopectin than that of normal. In ae du starches, however, elongation of the amylopectin chain and increase of the intermediate Fr. did not occur. Exhaustive degradation of starch-granules by glucoamylase showed that ae starches were more resistant to amylase. |
