Near-infrared reflectance correlated to 100-g wet-milling analysis in maize

An understanding of the genetic control of starch, protein, and oil concentrations in the corn (Zea mays L.) kernel is essential for improvement of grain quality. Because large numbers of progenies are needed for genetic studies, a rapid, accurate, analytical procedure is necessary. As part of a study to identify chromosomal regions associated with starch and protein, a rapid near-infrared reflectance (NTR) method and a more labor-intensive 100-g wet-milling procedure were compared for consistency in ranking families and identifying quantitative trait loci (QTL) using a set of 200 F2S1 families from the cross of the 70th generations of the Illinois High Protein (IHP) x Illinois Low Protein (ILP) corn strains. MR starch and wet-milling starch values were highly correlated (r = 0.80), as were NIR protein and gluten measured by wet-milling (r = 0.72). Chromosomal regions associated with MR starch and wet-milling starch were generally the same. Fiber concentration was significantly negatively correlated with starch and positively correlated with protein. Chromosome regions with significant associations with starch also had significant associations with fiber. The NIR method is satisfactory for measuring starch and protein in material with a wide range of variability in the early stages of a corn-breeding program.