GENETIC-VARIATION FOR STARCH THERMAL AND FUNCTIONAL-PROPERTIES AMONG NONMUTANT MAIZE INBREDS

Differential scanning calorimetry (DSC) has been used in previous stud ies to detect differences in thermal properties among starches of nonm utant maize (Zea mays L.) genotypes. This study was conducted to deter mine the magnitude of genetic and genotype by environmental effects on starch properties among a set of exotic and domestic inbred lines. Fu nctional properties of starches from selected lines exhibiting extreme DSC values also were investigated. Highly significant (P less-than-or -equal-to 0.01) differences for DSC starch thermal properties were see n among the lines. Starches from exotic lines generally had lower gela tinization onset temperature (T(o)), peak temperature (T(p)), and enth alpy (DELTAH). A highly significant (P less-than-or-equal-to 0.01) inb red by year interaction was present for all DSC parameters with the ex ception of DELTAH. Differences were observed in starch viscosities and gel strengths for six inbreds selected for highest and lowest T(p) DE LTAH, and range (R(n)). Several significant (P less-than-or-equal-to 0 .05) correlations occurred between DSC parameters and starch paste vis cosities and gel strengths. These data suggest that evaluation of star ches from nonmutant genotypes by DSC can be used to predict some funct ional properties. A practical application of DSC in breeding programs may include screening maize germplasm for extreme DSC values or popula tion improvement through recurrent selection.