Quantitative trait loci for metal accumulation in maize leaf

Abstract

Maize, as a major crop, has been investigated for decades for metal accumulation, but not in the context of leaf ionome to identify putative genetic factors participating in the control of metal accumulation. Our objectives were to analyze variation for copper (Cu), iron (Fe), potassium (K), manganese (Mn), magnesium (Mg), and strontium (Sr) concentrations in leaves of a maize mapping population, and to detect and determine the effects of quantitative trait loci (QTL) associated with the metal concentrations. Ear-leaf samples at the beginning of the silking stage was taken for elemental analysis (ICP-OES) of 290 F4 lines of a biparental population (B84×Os6-2) grown in field trials in Croatia. The population and parents differed significantly in Cu, Fe, K, Mg, Mn, and Sr concentrations. The population was mapped using sets of 56 SNP and 65 SSR polymorphic markers. Eleven significant QTLs were detected for all six metal concentrations. Of them, QTLs for Cu, Fe, and Mg were colocalized on chromosome 5 in the region of ys1 gene. Significant dominant effect of these QTLs supports the involvement of ys1 in accumula¬tions of these metals. Some QTLs had no obvious candidate genes offering the possibility of identifying unknown genes that affect metal accumulation.