2016 journal article
Susceptibility of Dent-Sterile Popcorn to the Ga1-m Gametophyte Factor
CROP SCIENCE, 56(5), 2594–2599.
The Ga1‐s allele is the foundation of dent‐sterile popcorn (Zea mays L. var. everta), where it is used as a genetic barrier to prevent pollen contamination, but its known genetic susceptibility to another allele at the same locus is problematic for the sustainability of Ga1‐s popcorn. The Ga1‐m allele overcomes the pollen barrier imparted by Ga1‐s, opening any system using it to potential contamination. The Ga1‐m allele, although previously thought rare, has been shown to be abundant in Mexican commercial maize (Z. mays L.), and has been identified in a US ex‐Plant Variety Protection (PVP) line. The requirement for specific evaluation to detect the allele, coupled with efforts to increase the genetic base of maize, create a considerable risk of the unintentional release of Ga1‐m‐carrying materials. Resistance to Ga1‐m has been previously identified, providing a possible way to eliminate the risk posed by Ga1‐m but comes in an unadapted sweetcorn background. Through field evaluation, we tested commercial and publically available popcorn for resistance to Ga1‐m, all of which were uniformly susceptible. There is, therefore, a need to identify and integrate Ga1‐m resistance into commercial popcorn inbred lines and hybrids. Although the use of existing Ga1‐m resistant sources is an option, background differences will likely be problematic for producing useable inbred lines. We suggest the use of molecular tools to aid in specific backcrossing of the Ga1‐m resistance allele or identification of Ga1‐m resistance in a popcorn background, for which we suggest an evolutionary‐based approach.