This barely merits the Research Blogging tag, because all I want to do here is raise a possibility, and a tenuous one at that. I confess that I was attracted in a high-speed scan of headlines, by this one: Leaving home ain’t easy: non-local seed dispersal is only evolutionarily stable in highly unpredictable environments. ((Snyder, R. (2010). Leaving home ain’t easy: non-local seed dispersal is only evolutionarily stable in highly unpredictable environments Proceedings of the Royal Society B: Biological Sciences, 278 (1706), 739-744 DOI: 10.1098/rspb.2010.1549)) The starting point is the common armchair argument that seeds disperse for three non-exclusive reasons: to escape changes in the environment they are leaving, to avoid overcrowding (and competition with sibs?) and to find and exploit new environments before other competitors.
Robin Snyder’s mathematical model seeks to understand how far seeds need to move from their parent to be reasonably certain of encountering different growing conditions. After all, “why ‘escape in space’ only to land somewhere more or less like where they started?” The models show that in almost all cases, dispersal tends to be not far enough to get away from the “parental” conditions. Only when favourable conditions are very fleeting is it worthwhile for some seeds to leave home far behind, as a “response to environmental unpredictability”.
Why bring this up here? Because the seeds of high-performing agricultural varieties are often dispersed hundreds or thousands of kilometres from the environments in which they were deemed successful. In theory they are being sent to places with very similar growing environments. But might this actually be an argument for sending seeds far from home specifically as a strategy to enable the farmers selecting them to respond to environmental unpredictability?