COMPARISON OF WET-MILLING PROPERTIES AMONG MAIZE INBRED LINES AND THEIR HYBRIDS

A 100-g laboratory wet-milling procedure was used to compare wet-milling properties among 15 maize inbred lines and 20 related hybrids. Analyses of variance indicated sufficient precision in measurement of wet-milling yields for detection of differences among genotypes (inbred lines, hybrids). Significant divergence of hybrid from mid-parent values indicated that larger kernels of hybrids were lower for germ and fiber yields, and higher for gluten yield and filtrate solids in comparison to their inbred parents. Gene action for starch yield and starch recovery appeared to be additive in nature. However, only the predictive model for starch yield (hybrid starch yield = 13.9 + 0.74 [mid-parent starch yield]) was significant. Positive correlations between wet-milling starch yield and starch content of kernels estimated by near-infrared reflectance spectroscopy were consistent among inbred lines and hybrids (r = +0.90 and r = +0.67, respectively), suggesting near-infrared reflectance as a potential tool in breeding for hybrids with enhanced starch extraction properties. The correlations between grain hardness and starch yield were r = -0.77 and r = -0.66 for inbred and hybrid-based evaluations, respectively, indicating the need to overcome this negative relationship when developing hybrids with both high starch yield potential and postharvest grain quality.