The gel‐chromatographic fractionation of amylose and amylopectin from starch was investigated, and the method was improved in the preparation of starch solution by adopting perchloric acid as solvent. The four types of maize starch e.g. normal‐, waxy‐, amylo‐ and amylo‐waxy‐type, were investigated by this improved gel‐chromatographic method, and the ratios of each fractionated component were estimated.

A reliable method for the determination of the amylose and amylopectin fractions of starch has been developed using paper chromatography. Starch is separated into amylose and amylopectin fractions on a filter paper strip by descending paper chromatography in iodine vapor, using 40% HClO4 solution as the solvent. These fractions are collected separately by irrigating the strip with 40% HClO4 solution. After adding iodine and potassium iodide to the eluate, the iodine complexes of these components are collected by centrifugation and are treated to remove the iodine. The concentration in these iodine-free fractions is determined colorimetrically by the anthrone-sulfuric acid method. In this way, the amylose and amylopectin contents of starch are determined without reference to authentic amylose and amylopectin preparations separated from the same starch specimen by the Schoch method. The values by thismethod represent more true starch contents than those obtainedby the other current methods.

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Amylo-maize was crossfertilized with waxy-maize, and bred F,-and F,-seeds were investigated based on phenotype in genetics and on physical and chemical properties of starch. It was elucidated that F,-seeds became normal-type, but F,-seeds were assorted into 4 types, that were normal, amylo, waxy and a novel one. Analysis of all kernels of F, showed the ratios of the above 4 types to be 9:3:3:1. From the results, the genotypes of endosperm concerned with starch formation were deduced as (Ae --, Wx --), (ae ae ae, Wx --), (Ae --, wx wx wx), (ae ae ae, wx wx wx) respectively. The novel type was named "amylo-waxy" from its properties that the prepared starch was composed of amylopectin only as waxy, but its iodine stained color reaction was as blue as in amylose.