Qtl Mapping Of Nutrient Components In Maize Kernels Under Low Nitrogen Conditions

A set of 213 F-2:3 families were used to investigate the effects of nitrogen (N) on grain yield and the concentrations of three nutrient components in maize (Zea mays L.) kernels. A genetic linkage map was constructed using 189 SSR (simple sequence repeat) markers, spanning a total of 2003 cM, including 11 linkages, and the families were evaluated under high N and low N conditions at two farm locations. The results indicate that low N conditions may induce an increase in starch concentration, but a decrease in protein levels. Twenty-six quantitative trait loci (QTL) were detected for four measured traits in the two N treatments at both locations, including eight QTL for grain yield, seven QTL for oil content, six QTL for protein content and five QTL for starch content. The total number of QTL detected for the four measured traits under high N levels was greater than the QTL detected under low N conditions, and several QTL were identified that specifically expressed under different N conditions. These particular QTL could help provide greater understanding of the genetic basis of N-usage efficiency.