Detection of quantitative trait loci for kernel oil and protein concentration in a B73 and Zheng58 maize cross.

Maize (Zea mays L.) is one of the most important food crops throughout the world, and provides oil and proteins to humans and livestock. Kernel oil and protein content in maize are two complex quantitative traits. In order to identify quantitative trait loci (QTL) controlling oil and protein concentration in maize kernels, and to evaluate their genetic effects, QTL analysis was conducted on an F3:4 population derived from a cross between an inbred line with a low oil and protein concentration (Zheng58) and an inbred line with a higher oil and protein concentration (B73). A total of 189 polymorphic simple sequence repeat markers were used to construct a linkage map. Eleven QTLs for kernel oil concentration were detected on nine chromosomes, except for chromosome 9. A single QTL explained 4.6 to 11.1% of the phenotypic variance. Ten QTLs for kernel protein concentration were also detected on nine chromosomes, except for chromosome 9. A single QTL explained 4.2 to 11.4% of the phenotypic variance. Interestingly, novel QTLs for oil concentration (qOIL08-01 and qOIL10-01) and QTLs for protein concentration (qPRO01-01 and qPRO05-01) were specific to the population studied, which could explain 7.1 to 11.1% of the phenotypic variance. These results will provide better understanding of the genetic basis of oil and protein concentrations in maize. The markers closely linked with the QTLs will facilitate breeding of maize varieties with high oil and protein concentrations through molecular marker-assisted selection.