The maize Ga1-s allele confers protection against ga1 pollen in popcorn and dent corn

Abstract

Because corn pollen can be carried great distances by wind, maintaining genetic purity of corn grain is challenging. The challenge is substantially reduced in popcorn, which carries the Ga1-s allele preventing pollination by ga1 plants, which include the vast majority of non-popcorn commercial maize varieties in the U.S.. Ga1-s can be transferred into dent corn but the effectiveness of the Ga1-s allele in popcorn and dent corn has never been compared, which is important because each are regulated differently regarding GMO contamination. We compared pollen exclusion of commercial popcorn hybrids, Ga1-s dent corn hybrids and normal dent corn hybrids for their ability to exclude ga1 pollen using a sensitive field-based assay. While both popcorn and Ga1-s dent corn had significantly better pollen exclusion than normal dent corn, popcorn was significantly better than Ga1-s dent corn on average. Some Ga1-s dent hybrids excluded as well or better than some popcorn lines suggesting that identification of hybrids comparable to popcorn is possible. The information in this study will support revised gene purity regulations potentially decreasing costs and increasing genetic purity of organic corn.

Marker-assisted Ga1-S incorporation into white maize hybrid's parental lines

“…The quantity of yellow kernels on white lines was around 5%, so the process of MABB in this case was unsuccessful. The most likely explanation of our results, consistent with Lauter et al (2022), could be the presence of modifier genes that increase or decrease the effectiveness of pollen exclusion or that, alternatively, modifiers were lost during the backcrossing. These authors also concluded that converting dent corn varieties to Ga1-S requires careful testing for their ability to exclude pollen.…”