Predicting Outcrossing in Maize Hybrid Seed Production

Abstract

Controlling pollination of the female inbred is critical to achieve maximum kernel set and high levels of genetic purity in maize (Zea mays L.) hybrid seed production. Although kernel set associated with inbred fl owering dynamics is fairly predictable, it has not been possible to predict the level of outcrossing resulting from adventitious pollen entering the seed fi eld. Our objective was to combine our kernel set model with a new Lagrangian pollen dispersal model to determine whether outcrossing could be simulated from fl owering dynamics and estimates of pollen drift . Th is study was conducted in a commercial seed production fi eld in which male and female planting dates were varied to provide a range of fl owering synchronies and risk for outcrossing. Kernel production varied from 13.4 × 10 6 to 24.5 × 10 6 kernels ha −1 . Outcrossing at fi eld locations 100 to 170 m from an adventitious pollen source varied from 1.4 to 18% as determined by allelic variation at 13 loci. Th e kernel set model accurately simulated variation in kernel production (R 2 = 0.83; RMSE = 0.3 × 10 6 ) when silk receptivity was limited to 4 d. Percentage outcrossing due to adventitious pollen also was accurately simulated (R 2 = 0.78; RMSE = 0.8) for wind conditions and plant development patterns typically encountered in maize hybrid seed production. Th e combined kernel set and pollen dispersal models provide a novel and robust approach for defi ning management strategies to optimize kernel production and genetic purity.

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

“…These approaches make the reasonable assumption that the more local factors are taken into account, the more accurate the estimations at the field scale become. Recently, the biophysical approach was validated with success on individual experimental fields by Dietiker et al (2011) and Astini et al (2009) for hybrid and seed production fields, respectively. However, they are also extremely laborious to develop, due to the need to model each biological and physical process (Marceau et al, , 2012Viner et al, 2010;Chamecki et al, 2011).…”

“…However, they are also extremely laborious to develop, due to the need to model each biological and physical process (Marceau et al, , 2012Viner et al, 2010;Chamecki et al, 2011). Recently, the biophysical approach was validated with success on individual experimental fields by Dietiker et al (2011) and Astini et al (2009) for hybrid and seed production fields, respectively. However, because application of these models require so many site-specific parameters, it is not practical to use these models for specifying coexistence rules at the European scale.…”

Small‐Scale Circulations Caused by Complex Terrain Affect Pollen Deposition

“…8), suggesting that it may be possible to develop relationships between the quantity of pollen at a given location and the likelihood of gene flow. In fact, Astini et al (2009) have shown that a simple comparison between the quantity of adventitious pollen and the quantity of locally produced pollen could reasonably predict the likelihood of gene flow within a few hundred meters of an adventitious source. Comparison of our results with Watrud et al (2004) suggests it would be worth exploring a similar approach even at greater distances.…”

Scientific Opinion on application (EFSA-GMO-UK-2008-60) for placing on the market of genetically modified herbicide tolerant maize GA21 for food and feed uses, import, processing and cultivation under Regulation (EC) No 1829/2003 from Syngenta Seeds

“…Due to their characteristics, maize pollen grains settle to the ground rapidly and have usually a short flight range (Jarosz et al, 2005). However, vertical wind movements or gusts during pollen shedding can lift pollen up high in the atmosphere and distribute it over significant distances up to kilometres (Jarosz et al, 2005;Astini et al, 2009;Vogler et al, 2009;Hofmann et al, 2010). However, vertical wind movements or gusts during pollen shedding can lift pollen up high in the atmosphere and distribute it over significant distances up to kilometres (Jarosz et al, 2005;Astini et al, 2009;Vogler et al, 2009;Hofmann et al, 2010).…”

“…Approximately 95-99 % of the released pollen is deposited within about 50 m from the source. However, vertical wind movements or gusts during pollen shedding can lift pollen up high in the atmosphere and distribute it over significant distances up to kilometres (Jarosz et al, 2005;Astini et al, 2009;Vogler et al, 2009;Hofmann et al, 2010). Concentrations of viable pollen considerably decrease with height (Aylor et al, 2006) and distance (Jarosz et al, 2005) from the source.…”