Genetic basis of maize ear angle revealed by high-density single nucleotide polymorphism markers in four recombinant inbred line populations

Ear traits play a vital role in maize (Zea mays) yield. The ear angle (EA) has an obvious impact on corn yield and planting density as well as other maize ear traits. However, the genetic control of EA is still unclear. In this study, we identified quantitative trait loci (QTLs) for EA from four recombinant inbred line populations, BY815/DE3, BY815/K22, CI7/K22 and Mo17/X26-4, which were grown in three environments, and the genetic architecture of EA in maize was subsequently dissected. The results indicated that maize EA was highly heritable and was affected by both genotype and environment. Based on the genetic linkage map constructed using 56,110 bins as markers, nine effective QTLs for maize EA were detected locating on chromosomes 2, 3, 4, 6 and 7. These QTLs accounted for different EA variations ranging from 5.5% (qCIKEA6) to 7.6% (qBYKEA3). Moreover, 14 candidate genes were identified from the reduced QTLs using a bin-map method, which mainly encoded enzymes in signal transduction, transcriptional regulation and metabolism. Conclusively, our results can benefit further study of the genetic basis of EA and improve the maize EA quality through molecular breeding.