A mechanistic model of pollinator-mediated gene flow in agricultural safflower
Basic and Applied Ecology
In many species of crop plant, gene flow by cross-pollination is possible between spatially separate fields. To preserve a crop's varietal purity or to restrict ingress into conventional varieties of genetically modified (GM) genes, a quantitative understanding of gene flow is useful. Previous measurements of gene flow in safflower (Carthamus tinctorius L.), a crop with GM varieties, were made in plots of less than 1 ha. Here, I evaluate a mathematical model of field-to-field gene flow due to insect pollination using parameter values appropriate to a large agricultural field of safflower. The model was solved based on laboratory pollination experiments and observations made on a large (40 ha) safflower field in Lethbridge, Canada that was pollinated by honey bees (Apis mellifera) and bumble bees (Bombus spp.). The model estimated the maximum feasible level of bee-mediated, field-to-field gene flow to range between 0.05% and 0.005% of seed set (95% upper confidence intervals of 0.23% and 0.023%), depending on the composition of the bee fauna. These relatively low values emerged for two reasons: safflower has a high capacity for automatic self-fertilization; and bees undertook long foraging bouts in the field, which made between-field pollinations relatively rare. A strategy for minimizing GM gene flow should utilize a conventional safflower variety that has a high capacity for automatic self-fertilization and should allow the conventional plants to grow in large stands to encourage long foraging bouts by bees.
Copyright © 2010 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Basic and Applied Ecology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Basic and Applied Ecology, 2010, 11 (5), pp. 415–421 DOI: http://dx.doi.org/10.1016/j.baae.2009.12.006
Basic and Applied Ecology, 2010, 11 (5), pp. 415–421