The effect of improved varieties on PCE and poverty status
of the households is estimated with the nearest neighbor
(NNM) and kernel-based matching (KBM) models. 13 The
empirical results for all improved maize varieties and those
of hybrids in Chiapas and creolized in Oaxaca are given in Tables
5 and 6. The results in Table 5 show that the adoption of
improved maize varieties exerts a positive and significant impact
on the per capita expenditure in Chiapas. Specifically,
the NNM estimates suggest that the causal effect for all improved
maize varieties adoption on household welfare is about
MX$ 136 (US$ 14.6) in Chiapas and MX$ 173 (US$ 18.6) in
Oaxaca. This is the average difference in per capita expenditure
between similar pairs of households that belong to different
technological status. In terms of causal effects, the estimates
of the KBM appear to be similar to those of the NNM. The
NNM estimates on the probability of households falling below
the poverty line were 31% and 27% less than those of nonadopters
in Chiapas and Oaxaca, respectively.
The estimates for hybrid maize adoption in Chiapas and
creolized maize adoption in Oaxaca are also presented in
Tables 5 and 6, respectively, and they also show some interesting
results. The causal effect of adoption of maize hybrid on
the per capita expenditure in Chiapas is positive and statistically
significant and ranges between MX$ 116 (US$ 12.5)
and MX$ 123 (US$ 13). This significant increase in PCE
helped adopters reduce poverty levels by 38%. With regards
to the impact of creolized maize variety adoption in Oaxaca,
both NNM and KBM estimates also show that the adoption
of improved germplasm contributed positively to an improvement
in the welfare of households. In particular, PCE of
adopters was almost MX$ 200 higher than those of nonadopters,
while the poverty level was almost 20% lower than that of
nonadopters. These results suggest that the causal effect of hybrid
variety adoption on poverty reduction is greater in Chiapas
than the creolized variety in Oaxaca. The differential