Identification of QTL for zinc and iron concentration in maize kernel and cob

To provide theoretical and applied references for biofortification of maize by increasing Zn and Fe concentration, the correlation and quantitative trait loci (QTL) of four mineral-related traits, i.e. zinc concentration of kernel (ZnK), zinc concentration of cob (ZnC), iron concentration of kernel (FeK) and iron concentration of cob (FeC) were studied for two sets of F-2:3 populations derived from the crosses Mu6 x SDM (MuS) and Mo17 x SDM (MoS) under two different environments (CQ and YN). The parental lines were very different in Zn and Fe concentration of kernels and cobs. A large genetic variation and transgressive segregation of two F-2:3 populations were observed for the four traits. The heritability of FeK was relatively lower (< 0.6) than other three traits (> 0.7). Analysis for each environment and joint analysis across two environments were used to identify QTL for each population. 16 and 15 QTL were identified in CQ and YN respectively via single environment analysis, some of which were identical in different environments and were also detected in joint analysis. The common regions for same trait at different environments were 3 and 5 in MuS and MoS respectively. Compared with the IBM2 2008 Neighbors Frame6, the distribution and effect of some QTL in two populations were highly consistent and many QTL on chromosome 2, 7 and 9 were detected in both populations. Moreover, several mineral QTL co-localized with each other for both populations such as the QTL for ZnK, ZnC, FeK and FeC on chromosome 2, QTL for Znk, FeK and FeC on chromosome 9 and QTL for ZnK and ZnC on chromosome 7, which probably were closely linked to each other, or were the same pleiotropic QTL.