Genetic Analysis of Maize (Zea mays L.) Endosperm Vitreousness and Related Hardness Traits in the Intermated B73 × Mo17 Recombinant Inbred Line Population

Abstract

Variation for maize (Zea mays L.) kernel vitreousness is of interest in the improvement of maize for human and ruminant nutrition based on its connection with starch degradability in the rumen as well as the concentration of lysine and other essential amino acids. In this trial, 199 recombinant inbred lines (RILs) from the intermated B73 and Mo17 (IBM) population and 133 testcrosses of the IBM RIL with inbred W604S were grown in two replications in two Wisconsin locations in 2007. Ears were harvested at physiological maturity and ground kernel samples were scanned using near‐infrared spectroscopy (NIRS). Samples representing the NIRS spectral range were scored for kernel vitreousness using a horizontal light box and for kernel hardness using the Stenvert hardness test. The RIL phenotypes for hardness and vitreousness followed a normal distribution, and transgressive segregation was seen for both traits. Correlations between inbreds and respective testcrosses for hardness and vitreousness were significant and positive. The correlation between hardness and vitreousness was also positive. Quantitative trait loci (QTL) analysis of this population found 33 QTL for hardness and vitreousness with several QTL overlapping across traits. The IBM population represents a good model for the study of variation of kernel vitreousness in U.S. Corn Belt Dent germplasm and the genomic regions identified could be useful for the genetic improvement of maize varieties with enhanced nutritional composition.