Variation of starch granule size in tropical maize germ plasm
1996
Campbell, M.R. | Li, J. | Berke, T.G. | Glover, D.V.
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 less than or equal to 0.01) differences were seen among the populations for mean granule diameter. Granule mean and mode diameter ranges were 16.2-18.2 micrometers and 14.2-16.8 micrometers, 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 less than or equal to 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 micrometers) and the highest gelatinization onset (To), peak (Tp), and conclusion (Tc) temperature. A correlation analysis between mean and mode granule diameter values and thermal properties (To, Tp, and Tc) revealed several highly significant positive correlations.
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