The variability in thermal properties among 62 S-3 lines derived from
a high-yielding exotic corn (Zea mays) population, Antigua 1 (PI 48499
0), was evaluated by differential scanning calorimetry (DSC). The S-3
lines were grown in Puerto Rico (1990-1991) and Georgia (1994). Separa
te single-kernel starch extractions for five kernels (five replicates)
from each line grown in each location were performed, and the starch
was analyzed. The DSC values reported included gelatinization onset (T
-oG), range (R-G), enthalpy (Delta H-G), and peak height index (PHI) a
nd retrogradation onset (T-oR), range (R-R), enthalpy (Delta H-R), and
percent retrogradation (%R) (an indication of the stability of gelati
nized starch after storing at 4 degrees C for 7 days). Significant dif
ferences (P < 0.05) were found among the 62 lines of Antigua 1 for T-o
G, R-G, and PHI and highly significant differences (P < 0.01) were fou
nd for Delta H-G. The starches from plants grown in Georgia (1994) had
significantly (P < 0.05) greater T-oG, Delta H-G, and PHI but a signi
ficantly lower R-G than those from Puerto Rico (1990-1991). These data
suggest that the starch from plants grown in Georgia (1994) might hav
e a greater degree of crystallinity than that from Puerto Rico (1990-1
991). None of the retrogradation values were significantly different a
mong starches of the 62 lines of Antigua 1 and the starches from plant
s grown in the two locations.