Large-Scale Cloning and Characterization of Genes Controlling Grain Yield for Deciphering of the Molecular Basis of Grain Yield and Development of a Gene-Based Breeding System in Maize

Genes are crucial to decipher the molecular basis of traits, to address the problems in agriculture, and to develop toolkits for enhanced plant breeding. However, few genes have been cloned for many traits important to agriculture although many are known to be controlled by numerous genes. Maize is a world-leading crop for food, oil and bioenergy, for all of which grain yield is the most important. Here, we report systems analysis of a large number of genes controlling grain yield that were cloned using a newly-developed genome-wide high-throughput gene/QTL cloning system. We phenotyped 14 major grain yield and quality traits of two populations consisting of 221 maize lines, including grain yield per se, sequenced the full-length cDNA of all genes expressed in developing ear shoots, profiled the expressions of all the genes and sequenced related genomic sequences of all 221 lines using next-generation sequencing technology. Integrative analysis of the datasets using the new gene/QTL cloning system has identified a large number of genes controlling maize grain yield. These grain yield genes were found to be involved in numerous metabolism pathways. Currently, we are studying the molecular basis of grain yield and developing a gene-based breeding system in maize. These results provide a deep understanding of the molecular basis of grain yield and toolkits enabling enhanced molecular breeding in maize based on the genotypes, activities, gene/gene interactions and gene/non-gene element interactions of the genes controlling the trait of interest.