The effects of the US Plant Variety Protection Act on wheat genetic improvement

In our model of partially appropriable invention, if the US Plant Variety Protection Act (PVPA) of 1970 succeeded in strengthening intellectual property protection for plant breeders, it should have led to increases in investment in varietal R&D, improved varietal quality, and enhanced royalties. These hypotheses are tested using data on US wheat. We find that the PVPA may have stimulated public (but not private-sector) investment in wheat varietal improvement but that the PVPA did not cause any increase in experimental or commercial wheat yields. These findings indicate that the PVPA had little impact on excludability or appropriability in wheat varieties.