In light of a burgeoning global population, the public is becoming more and more aware that an adequate food supply cannot be taken for granted. Thus the question of sufficient agricultural productivity, or yield—defined as the amount of a crop produced per unit of land over a specified amount of time—has received considerable attention, especially given already reported episodes of reduced food availability in some parts of the world. Although current food production is actually adequate when measured on a global scale, with issues other than agricultural yield being of greatest importance at present for determining access to...

Increasing yield has long been a major motivation of agricultural research in the United States. As data from the U.S. Department of Agriculture (USDA) show, yields of major field (or commodity) crops such as corn, wheat, and soybeans have been rising steadily since early in the twentieth century. For example, corn yields improved by several percent per year through mid-century, though more slowly over the past several decades, as illustrated by Figure 1 (National Agricultural Statistics Service 2009). Today’s average corn yields of about 150–160 bushels per acre are some six-fold higher than corn yields in 1930. Although not...

Many have claimed that current GE crops increase yield (for example, Biotechnology Industry Organization 2009; Fernandez-Cornejo and Caswell 2006; McLaren 2005; Barboza 1999; Ibrahim 1996). To evaluate these claims we need to be clear on whether they apply to potential or operational yield, and we need to examine GE crops for which there are sufficiently robust data to draw reliable conclusions. Several Bt genes—insecticidal genes from the bacterium Bacillus thuringiensis—for achieving insect resistance in corn, as well as GE methods for instilling herbicide tolerance (HT) in corn and soybeans, have been widely commercialized for up to 13 years...

GE crops are not the only alternative to the U.S. agricultural practices predominantly used for controlling corn borers, rootworms, and weeds. Other methods of growing crops may provide benefits when compared to those of current industrial high-input agricultural production, and at the same time produce comparable yields. They include organic agriculture (pursued, for example, in accordance with the USDA standards) and “low-external-input” (LEI) methods that apply agro-ecological principles to control pests.¹² Conventional crop breeding may provide additional possibilities, especially for resistance to insects.

Because organic and many tested LEI systems do not use transgenic crops, they could provide a good...

This chapter examines the promise of the next generation of GE traits to improve crop productivity, and it highlights some of the accompanying challenges. The focus is primarily on genes for increased potential yield, but the issues explored also apply to traits for increasing operational yield. It must be noted, however, that many of the genes now being considered for increasing yield involve greater genetic, biochemical, and phenotypic complexity than current genes for insect resistance or herbicide tolerance, and this complexity will sometimes exacerbate the tendency of GE to produce side effects, some of which may be unacceptable. We also...

While crop GE has been hailed by some as critically important for ensuring adequate food supply in the future, it has so far produced only small increases in yields in the United States. Our review of available data on transgenic Bt corn, as well as on transgenic HT corn and soybeans, arrives at an estimated total yield benefit of about 3–4 percent for corn. Individual farmers may achieve substantially higher yields from Bt corn under certain circumstances, such as when corn borer infestations are high, and they may also use Bt corn to reduce exposure to chemical insecticides and...