The instant invention discloses utilization of a cDNA clone to construct sense and antisense genes for inhibition of starch synthase enzymatic activity in corn. More specifically, this invention concerns a method of controlling the starch fine structure of starch derived from the grain of cereal crops comprising: (1) preparing a chimeric gene comprising a nucleic acid fragment encoding a starch synthase structural gene or a fragment thereof, operably linked in either sense or antisense orientation on the upstream side to a nucleic acid fragment encoding a promoter that directs gene expression in corn endosperm tissue, and operably linked on the downstream side to a nucleic acid fragment encoding a suitable regulatory sequence for transcriptional termination, and (2) transforming cereal crops with said chimeric gene, wherein expression of said chimeric gene results in alteration of the fine structure of starch derived from the grain of said transformed cereal crops compared to the fine structure of starch derived from cereal crops not possessing said chimeric gene.