MOLECULAR MARKERS ASSOCIATED WITH MAIZE KERNEL OIL CONCENTRATION IN AN ILLINOIS HIGH-PROTEIN X ILLINOIS LOW-PROTEIN CROSS

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 qua ntitative trait loci (QTL) influencing kernel oil concentration and ke rnel weight in a maize (Zen mays L.) population derived from a cross o f Illinois High Protein (IHP) x Illinois Low Protein (ILP). The parent al 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 g (ILP) to 41.1 g (IHP). One hundred polymorphic RFLP loci spaced throughout the maize genome were scored in a segregating population of 100 S-1 families. Ke rnel 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 13 chromosome arms with oil con centration and 18 marker loci on 10 chromosome arms with kernel weight were identified. These results demonstrate the effectiveness of ident ification of QTL for oil concentration in strains divergently selected for protein concentration for 76 cycles. Clusters of two or more mark er loci in the same chromosomal region were significantly associated w ith oil concentration at four different chromosomal locations and with kernel weight at four chromosomal locations. The detection of relativ ely few clusters of marker loci associated with genomic regions contro lling oil concentration suggests the development of high oil maize ger mplasm via RFLP marker-assisted selection may be feasible.