However, the bush form of P. vulgaris appears less stable as a local landrace, and there appears to be a distinction between the vine form of P. vulgaris and the bush form. The vine form follows the maize landrace pattern where 80% of farmers' seed is greater than 20 years old, and only 13% of seed comes from outside of the village. The bush form, however, has a higher percentage of new seed lots, 40%, and 21% of the seed comes from outside of the village. The seed lots listed as "other" are mostly P. Vulgaris bush types as well and follow a similar pattern of recent acquisition and high levels of introduction from outside the village. This indicates that P. Vulgaris is less entrenched genetically in local sources, and farmers rely less on saved seed to maintain local populations.

Across all bean types, 27% of farmers reported having changed bean seeds at some time. Of those who reported changing, 50% reported using seed from local, village sources, 25% used seed from another village, and 25% used seed purchased in the market. Again, it is possible that the idea of seed adaptation to local conditions is much stronger for maize than for beans. Furthermore the large number of bean seed lots purchased as food seed in the market indicates a large inflow of germplasm and the more precarious nature of local P. vulgaris diversity. Furthermore, the market beans are principally imported from other states within Mexico and the United States and, thus, represent a flow of genetic material into local populations.

Farmers who reported changing their bean seed were asked why they had changed, and the results are reported in Table 7-9. The most common reason reported was that they had lost the seed from the previous season.

Table 7-9. Reasons for changing bean seed
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