Male Fertility Genes In Wheat (Triticum aestivum) and Their Use In Seed Production Technology

The Seed Production Technology (SPT) currently deployed at DuPont Pioneer for maize hybrid seed production utilizes the ability of a transgene to restore fertility to a nuclear male-sterile mutation and enables the production of all male-sterile, non-transgenic progeny. A seed sorting component of the transgene enables a quality control step in the early stages of the process. The core of the SPT process, however, is firmly based on male-sterility.  Bread wheat (Triticum aestivum) is a hexaploid crop which is difficult to screen for mutants due to presence of three genomes. Using both forward and reverse genetics approaches several male fertility genes in wheat have been identified which when mutated, confer male-sterile phenotype. The forward genetics approach included positional cloning of a gene for a known male-sterile mutant, wheat ms1. For reverse genetics approaches, information from known male fertility genes from other monocot species were used to direct mutations in the corresponding wheat genes using double-strand break technologies. Functional analysis of these genes and their mutations showed that male fertility in wheat can be attributed to a single homeolog in some instances whereas all three homeologs are required for others. Even when all three homeologs are required each genome may have a differential contribution towards male fertility.