I. Introduction
It was estimated that around 100 million people are currently suffering from hunger and this will become more serious when the world’s population grows to 9 billion in 2050 [1]–[4]. Maize is one of the three major crops in the world, whose yield needs to be increased to face the challenge. Currently, improving crop yield from breeding is mainly through genomic methods [5], which have successfully solved the “long period” and “low-efficiency” deficiencies of traditional breeding methods based on human experience. However, genomic methods show weakness in selecting some agronomic traits, which are controlled by both biotic and abiotic factors [6].