Identification of the QTLs for grain yield using RIL population under different nitrogen regimes in maize

Quantitative trait locus (QTL) mapping can provide useful information for breeding programs, since it allows the estimation of genomic locations and genetic effects of chromosomal regions related to the expression of quantitative traits. To realize the genetic basis of grain yield of maize (Zea mays L.), a recombinant inbred line (RIL) population and two nitrogen (N) regimes were used to detect the QTLs for grain yield in maize, as a result, a total of six QTLs associated with grain yield per year (GYPE) were identified on chromosomes 1 (one), 6 (one), 8 (two) and 9 (two), with 0 - 12.0 cm of mapping interval between QTLs and their nearest markers. The three QTLs identified under high N regime could explain 18.07% of phenotypic variance, and could increase GYPE from 3.91 - 5.40 g, due to positive additive effects. Whereas, the three QTLs located under low N regime could account for 20.96% of phenotypic variance, and due to negative additive effects, they could decrease GYPE from 3.40 to 6.68 g. These results were beneficial for realizing the genetic basis of GYPE and developing marker-assisted selection in maize breeding project.