Cereal Chem. 71:464-468   |  VIEW ARTICLE


Dosage Effect at the Sugary-2 Locus on Maize Starch Structure and Function.

M. R. Campbell, P. J. White, and L. M. Pollak. Copyright 1994 by the American Association of Cereal Chemists, Inc. 

Structural characteristics and functional properties of starches isolated from kernels of a sugary-2 (su2) dosage series were examined to determine whether the normal allele (Su2) was completely dominant to the recessive allele (su2). Differential scanning calorimetry revealed intermediate values for gelatinization onset, gelatinization peak, range, total enthalpy, and retrogradation among genotypes possessing one and two mutant su2 alleles. No effect of gene dosage on amylose content was observed, but X-ray diffraction patterns revealed an intermediate degree of crystallinity relative to normal and mutant genotypes upon addition of two su2 alleles. Development of a peak at 19 degrees 2(theta) became more evident upon increasing doses of the su2 allele. Viscosity of the starch paste and gel strength resulting from the genotype possessing two doses of the su2 allele exceeded that of both mutant and normal genotypes. An intermediate retrogradation as detected by differential scanning calorimetry and from gel strengths of starches after storage for seven days suggested an increased stability of the Su2su2su2 starch relative to that of normal starch.