QTL for maize grain yield identified by QTL mapping in six environments and consensus loci for grain weight detected by meta-analysis

Grain yield is the most important and complicated trait in maize. In this study, a total of 498 recombinant inbred lines (RIL) derived from a biparental cross of two elite inbred lines, 178 and P53, were grown in six different environments. Quantitative trait locus (QTL) mapping was conducted for three grain yield component traits (100 grain weight, ear weight and kernel weight per plant). Subsequently, meta-analysis was performed after a comprehensive review of the research on QTL mapping for grain weight (100, 300 and 1000) using BioMercator V4.2. In total, 62 QTLs were identified for 100 grain weight, ear weight and kernel weight per plant in six environments. Forty-three meta-QTLs (MQTLs) were detected by meta-analysis. A total of 13 candidate genes homologous to eight functionally characterized rice genes were found, and four candidate genes were located in the two hot spot regions of MQTL1.5 and MQTL2.3. Our results suggest that the combination of literature collection, meta-analysis and homologous blast searches can offer abundant information for further fine mapping, marker-assisted selection (MAS) breeding and map-based cloning for maize.