This study makes use of data on wheat production in the Punjab of Pakistan from 1979 to 1985 to 1) examine patterns of varietal diversity in farmers' fields both at the regional and district levels and 2) identify how and ...

The theory of impure public goods is used to demonstrate why farmers may nor grow wheat cultivars with the socially desirable level of rust resistance. First, they may grow cultivars that are high yielding though susceptible ...