R. Ford Denison's "Darwinian Agriculture"

R. Ford Denison is adjunct professor of ecology, evolution, and behavior at the University of Minnesota and taught crop ecology at the University of California, Davis.

He applied the “Page 99 Test” to his new book, Darwinian Agriculture: How Understanding Evolution Can Improve Agriculture, and reported the following:

By page 99 I have introduced the challenges facing agriculture, reviewed some key principles from evolutionary biology, critiqued tradeoff-blind biotechnology, and I am starting to critique tradeoff-blind approaches inspired by nature. I argue that taking a cue from nature can indeed suggest the superiority of perennials over annuals, in some environments. But the same logic argues against current attempts to convert perennials into grain crops. A plant that puts more of its limited resources into grain (seeds) won't be able to make as much root (stabilizing soil) or build up the reserves that allow it to survive unfavorable conditions.

A perennial plant could produce more seeds in a given year by using more of its stored resources—putting its long-term survival at risk—only to have all of its seedlings destroyed by drought, fire, or grazing animals. It may be safer to produce a few seeds each year, over many years. That’s what many perennials do, as shown by the pathetic seed production (but good survival) of oak trees and many prairie plants, discussed in the preceding chapter.

But is some increase in seed production possible, without losing perenniality? Starting from a low baseline, a small increase might increase the risk of dying only slightly. For example, a perennial that puts only 5 percent of its photosynthate into reproduction might be able to double its seed production to use 10 percent of photosynthate, with only a small increase in the risk of early death. Plant breeders working to raise seed yields of these plants might therefore achieve significant increases at first—a doubling in seed yield, wow!—unknowingly accepting small increases in risk in exchange for increased yield. For seed yields to approach those of annuals, however, plants would have to put all available resources into seed production at the end of the growing season, as annuals do, making death almost certain.

So much for theory. How much actual progress has been made in breeding perennial grains? A previous 25-year effort to develop perennial wheat...

The last half of the book argues that, with more attention to tradeoffs, both biotechnology and approaches inspired by nature have untapped potential.

Learn more about Darwinian Agriculture at the Princeton University Press website.

--Marshal Zeringue