Updated Empirical Model of Genetically Modified Maize Grain Production Practices to Achieve European Union Labeling Thresholds

Abstract

An updated empirical approach is proposed for specifying coexistence requirements for genetically modified (GM) maize (Zea mays L.) production to ensure compliance with the 0.9% labeling threshold for food and feed in the European Union. The model improves on a previously published (Gustafson et al., 2006) empirical model by adding recent data sources to supplement the original database and including the following additional cases: (i) more than one GM maize source field adjacent to the conventional or organic field, (ii) the possibility of so‐called “stacked” varieties with more than one GM trait, and (iii) lower pollen shed in the non‐GM receptor field. These additional factors lead to the possibility for somewhat wider combinations of isolation distance and border rows than required in the original version of the empirical model. For instance, in the very conservative case of a 1‐ha square non‐GM maize field surrounded on all four sides by homozygous GM maize with 12 m isolation (the effective isolation distance for a single GM field), non‐GM border rows of 12 m are required to be 95% confident of gene flow less than 0.9% in the non‐GM field (with adventitious presence of 0.3%). Stacked traits of higher GM mass fraction and receptor fields of lower pollen shed would require a greater number of border rows to comply with the 0.9% threshold, and an updated extension to the model is provided to quantify these effects.

Combination Approach of Border Rows and Isolation Distance for Securing Coexistence of Non‐Genetically Modified and Genetically Modified Maize

“…One of the prescribed coexistence measures that has to be taken by the GM farmer is the planting of 24 rows of non-GM maize at the GM field edge; none of the samples taken between 2006 and 2010 from conventional maize fields located in the vicinity of Bt maize fields had a GM content above 0.8%. The authors updated their model approach in 2013 by including further data sets of coexistence field trials and considering multiple pollen sources, stacked GM varieties containing more than one GM trait, and non-GM fields with lower pollen shed than the GM-maize fields (Marceau et al, 2013). Until now, to our knowledge, no further published information on the efficacy of non-GM maize border rows is available.…”

“…However, due to the lack of control fields in the above-mentioned studies and surveys, an evaluation of the efficacy of border rows is difficult. Marceau et al (2013) calculated several combinations of isolation distances and border rows for the worst case, that is, a 1-ha conventional maize field is surrounded on all four sides by GM maize fields. However, in spite of this knowledge gap some papers give recommendations for isolation distance and border row combinations to ensure not exceeding the labeling threshold based on mathematical models.…”

“…In a 3-yr field study, we tested the efficacy of a combination of border rows and isolation distance as a coexistence measure for small-structured agricultural landscapes. For regions with a small-structured agricultural landscape (i.e., field sizes ~1 ha), small isolation distances might not be effective enough to keep the GM content in the entire harvest below the labeling threshold (Marceau et al, 2013), whereas large distances might not be practicable in these agricultural areas due to space limitations. Kernel color was used as a marker to quantify gene flow.…”

Risks of Pollen-Mediated Gene Flow From Genetically Modified Maize During Co-Cultivation With Usual Maize Varieties

“…Кукуруза -однодомный ветроопыляемый вид, растения в высоту достигают 3 м (иногда до 6-7 м), в связи с чем повышается риск распространения пыльцы ГМ-сортов, переносимой ветром на десятки и сотни метров (7,8). На перенос пыльцы влияют многие факторы: ветер (скорость и направление), дождь (влажность), физиология (жизнеспособность), количество пыльцы, характер ландшафта, размеры, форма и ориентация реципиентного поля, синхронность цветения донора и реципиента пыльцы (9).…”

“…Данные для новой модели были получены из базы данных по экспериментам, проведенным в 2000-2010 годах в Германии, Испании, Италии, Канаде, Нидерландах, Польши, Румынии, Словакии, Франции и США. Согласно этой модели, для 1 га неГМ-поля, окруженного со всех четырех сторон ГМ-полями, достаточно 12 м пограничных рядов в сочетании с 12 м полосы под паром для обеспечения порогового значения 0,9 % (на 95 % уровне значимости), установленного ЕС (9). На основе сравнения четырех методов оценки наличия ГМ-кукурузы на полях неГМ-реципиентов с математической обработкой результатов был предложен более надежный способ регистрации ГМскрещиваний по всей глубине поля (36).…”