QTL mapping for leaf area in maize (Zea mays L.) under multi-environments

Leaves are the main organs of photosynthesis in green plants. Leaf area plays a vital role in dry matter accumulation and grain yield in maize (Zea mays L.). Thus, investigating the genetic basis of leaf area will aid efforts to breed maize with high yield. In this study, a total of 150 F7 recombinant inbred lines (RILs) derived from a cross between the maize lines Xu 178 and K12 were used to evaluate three ear-leaves area (TELA) under multi-environments. Inclusive composite interval mapping (ICIM) was used to identify quantitative trait loci (QTLs) for TELA under a single environment and estimated breeding value (EBV). A total of eight QTLs were detected under a single environmental condition, and four QTLs were identified for EBV which also can be detected in single environment. This indicated that the EBV-detected QTLs have high genetic stability. A major QTL (qTELA_2-9) located in chromosome bin 2.04/2.05 could be detected in four environments and has a high phenotypic contribution rate (ranging from 10.79 to 16.51%) that making it a good target for molecular breeding. In addition, joint analysis was used to reveal the genetic basis of leaf area in six environments. In total, six QTL×environment interactions and nine epistatic interactions were identified. Our results reveal that the genetic basis of the leaf area is not only mainly determined by additive effects, but also affected by epistatic effects environmental interaction effects.