Molecular Markers Associated with Maize Kernel Oil Concentration in an Illinois High Protein × Illinois Low Protein Cross

Abstract

The Illinois Long Term Selection Strains offer a unique opportunity to investigate the quantitative genetic basis of kernel chemical traits. This study was conducted to determine the number and magnitude of quantitative trait loci (QTL) influencing kernel oil concentration and kernel weight in a maize (Zea mays L.) population derived from a cross of Illinois High Protein (IHP) × Illinois Low Protein (ILP). The parental strains had been divergently selected for protein concentration for 76 cycles, yet varied in oil concentration from 29 g kg−1 (ILP) to 54 g kg−1 (IHP) and in 300 kernel weight from 76.5 (ILP) to 41.1 g (IHP). One hundred polymorphic RFLP loci spaced throughout the maize genome were scored in a segregating population of 100 S1 families. Kernel oil concentration and kernel weight were obtained from replicated field trials grown during 1990 and 1991. Significant (P < 0.05 level) QTL associations of 25 marker loci on chromosome arms with oil concentration and 18 marker loci on 10 chromosome arms with kernel weight were identified. These results demonstrate the effectiveness of identification of QTL for oil concentration in strains divergently selected for protein concentration for 76 cycles. Clusters of two or more marker loci in the same chromosomal region were significantly associated with oil concentration at four different chromosomal locations and with kernel weight at four chromosomal locations. The detection of relatively few clusters of marker loci associated with genomic regions controlling oil concentration suggests the development of high oil maize germplasm via RFLP marker‐assisted selection may be feasible.