Genetic diversity in the major U.S. field crops is an important defense against pest or disease epidemics. If most crop varieties have common characteristics due to common ancestors, then the crop may be susceptible to a new disease or insect. An example was when the U.S. corn crop experienced Southern corn leaf blight. This disease attacked almost all hybrids in which the seed was produced using a particular male sterile plant. As a result, corn production fell 15 to 20 percent in 1970.
Some economists studying intellectual property rights (IPR) imply that the Plant Variety Protection Act (PVPA) of 1970 will reduce genetic diversity (Schmid, 1985). They give three reasons: (i) Stronger IPR will encourage private plant breeding, which will crowd out public sector breeding. (ii) Private breeding will not contribute to genetic diversity because private breeders use popular public varieties as parents and need to perform only the minimum amount of cosmetic breeding to qualify a variety as new under PVPA. (iii) PVPA uniformity and stability requirements make retaining genetic variability difficult for private breeders. If breeders retain variability, varieties will not be uniform, will change over time, and will not qualify as varieties under PVPA. Thus, under PVPA, the number of public varieties will decline. The number of private varieties and the total number of varieties may increase, but little genetic diversity will exist.
IPR supporters argue that IPR increases genetic diversity. Former research director for Pioneer Hi-Bred, Dr. Donald Duvick, explains:
CSRS: Cooperative States Research Service
HRW: Hard Red Winter
IPR: Intellectual Property Rights
PVPA: Plant Variety Protection Act
SRW: Soft Red Winter
... seed companies do promote and in-
crease genetic diversity on the farm,
to the extent that they successfully breed
and sell seed of increasing numbers
of crop varieties. Maintenance of nu-
merous and relatively distinct breeding
pools (separation of commercial breed-
ing programs) is encouraged and aided
by Breeders' Rights laws, utility patents
on plant germ plasm and the "self-
patenting" nature of hybrid crops. A
common assumption is: the more seed
companies with proprietary products,
the more genetically different varieties
available to the farmer and, thus, the
more genetic diversity.
However, he admits that some companies perform cosmetic breeding:
... USA farmers have many more soy-
bean varieties available to them today
... unfortunately, many of these com-
mercial soybean varieties are very close
relatives, if not essentially identical ...
Some commercial seed companies, un-
fortunately, tend to ignore the legal (and
financial) imperatives for genetic diver-
sity among seed companies in their
eagerness to share, legally or otherwise,
in use of the most popular genotypes.
The analysis here empirically tests the impact stronger IPRs on genetic diversity of wheat in farmers' fields. The analysis focuses on wheat for two reasons. (i) Agronomists have developed a quantitative measure of genetic diversity in wheat that one can use to test IPR impacts. (ii) PVPA stimulated more research into wheat (and soybeans) than all other crops (Butler and Marion, 1985; Perrin et al., 1983).
II. PVPA IMPACT ON BREEDING
Before 1900, farmers conducted most wheat varietal selection and introduction. The federal government played an important role by collecting wheat varieties from Europe and the Middle East and distributing them to American farmers. Between 1900 and 1920, the U.S. Department of Agriculture (USDA) and state universities started wheat selection and breeding programs and continued to introduce exotic varieties. …