Cereal Chem. 73 (5):536-538  |  VIEW ARTICLE

Carbohydrates

Variation of Starch Granule Size in Tropical Maize Germ Plasm (1).

M. R. Campbell (2), J. Li (3), T. G. Berke (4), and D. V. Glover (2,5). (1) Journal Paper 14876. Contribution of the Purdue University Agricultural Experiment Station. (2) Department of Agronomy, Purdue University, West Lafayette, IN. (3) Department of Agronomy, Huazhoug Agricultural University, Wahau, Hubei, Peoples Republic of China. (4) Asian Vegetables Research and Development Center, AVRDC, P.O. Box 42, Shanhua, Taiwan 741. (5) Corresponding author. Accepted June 18, 1996. Copyright 1996 by the American Association of Cereal Chemists, Inc. 

Granule size is an important characteristic of starch that can influence its functional and wet-milling extraction properties. Genetic variation for granule size has been found among maize (Zea mays L.) genotypes possessing single gene mutations affecting starch synthesis. In a previous study, 35 tropical and semitropical maize populations were examined for starch thermal properties. The purpose of this study was to evaluate these same populations for starch granule diameter using a laser light scattering technique. Highly significant (P <= 0.01) differences were seen among the populations for mean granule diameter. Granule mean and mode diameter ranges were 16.2-18.2 µm and 14.2-16.8 µm, respectively. Although ranges in mean granule diameter were not as large as those seen among mutant maize genotypes, they were greater than those of a group of normal (nonmutant) hybrids. Highly significant differences were also seen among ears within the populations. With few exceptions, mean granule diameter values varied significantly (P <= 0.05) within each of the populations, while the mode values varied to a lesser extent. NAL-TEL AM.T.B GUA220, an early maturing population from Central America, had the largest granule mean diameter (18.2 µm) and the highest gelatinization onset (T(o)), peak (T(p)), and conclusion (T(c)) temperature. A correlation analysis between mean and mode granule diameter values and thermal properties (T(o), T(p), and T(c)) revealed several highly significant positive correlations.