Pollen‐mediated gene flow from herbicide‐resistant yellow corn to non‐genetically engineered food‐grade white corn

Abstract

Nebraska is the number one producer of food‐grade white corn in the United States. Pollen‐mediated gene flow (PMGF) from genetically engineered high alpha‐amylase corn, known as Enogen corn, to food‐grade white corn can have undesirable outcomes. Alpha‐amylase can convert starch in white corn to sugar during or after its processing, degrading the quality of processed products. Thus, proximity to Enogen corn puts white corn production at risk. The objectives of this study were to evaluate the PMGF from herbicide‐resistant yellow corn to food‐grade white corn and assess the significance of wind speed and direction. Field experiments were set up using a Nelder‐wheel design in 2021 and 2022 in Nebraska, with yellow field corn as pollen donor in the center and white corn surrounding it as pollen receptor. At the end of the season, samples of white corn cobs were collected up to 50 and 70 m from four cardinal and ordinal directions, respectively. PMGF was detected by counting the number of yellow kernels on the white cobs. More than 4 million kernels were screened and the highest frequency of PMGF (0.0621–0.1950) was detected at the nearest distance (1 m). PMGF decreased exponentially with distance; however, it was still observed (0.0020–0.0032) at the greatest distance (70 m) evaluated in this study. Wind profile played a significant role in PMGF. Wind frequency (r = 0.58 ≤ 0.86) and wind run (r = 0.36 ≤ 0.95) were moderately to strongly correlated with PMGF in 2021 and 2022, respectively. The results are concerning for white corn growers due to the coexistence of Enogen corn and food‐grade white corn.