Starches isolated from kernels of two maize (Zea mays L.) inbreds and
their F1 progeny, grown after four planting dates, were evaluated for
differences in thermal properties. Differential scanning calorimetry (
DSC) was used to compare onset (T-o) and peak (T-p) temperature, range
(R(n)), and total enthalpy (Delta H) values of gelatinization. Amylos
e content (%AM) of samples was determined colorimetrically, and image
analysis was used to determine average diameters of granules. Signific
ant (P less than or equal to 0.05) increases for T-p and Delta H were
observed with later planting dates. Significant genotypic differences
also were seen for T-o, T-p, and Delta H. Later planting dates had no
effect on %AM or starch granule size. Genotypes ranked similarly for %
AM across each environment, and no differences were observed for avera
ge granule diameter. The presence of environmental effects on thermal
properties of the starch suggests that if small differences (1-2 degre
es C or <0.2-0.3 cal/g) are to be identified among nonmutant genotypes
, growing conditions may need to be controlled.