It is likely that there are large heterogeneities of preferences across
farm households. Any in-situ conservation effort should take these
heterogeneities into consideration. Additional information on the
factors contributing to the private value that farmers assign to crop
varieties may help to identify a strategy for ensuring the conservation of
the crop genetic resources that are embodied in landraces while at the
same time minimizing the costs (Brush and Meng, 1998). To account for
observed heterogeneity of preferences across farm households, we also
estimated models where a set of socio-economic characteristics were
interacted with the attributes. Due to potential multicollinearity
problems, it was not possible to include all interactions between the
explanatory variables and the four crop variety attributes. The results of
the RPL model are presented in Table A2 in the Appendix. What we will
focus on here is instead the estimated marginal WTPs. A number of
comparisons can be made, but we focus on two. For the binary
household variables, we present the marginal WTP for each category of
the variables. Table 6 presents the results of the marginalWTP estimates
for all the binary variables. For simplicity, we only report the
unconditional WTP estimates i.e. WTP is estimated as the ratio of the
respective attribute coefficients to the price coefficient.