Evaluation of Evolution and Diversity of Maize Open-Pollinated Varieties Cultivated under Contrasted Environmental and Farmers' Selection Pressures: A Phenotypical Approach

OPVs (open pollinated varieties) of cross pollinated crops are genetically heterogeneous and therefore likely to evolve over generations, under natural and human selection, which gives them a strong potential for organic and low input farming. OPVs of maize were cultivated and selected by different farmers in France and Italy for 2 generations. The third year, they were phenotypically evaluated for evolution, adaptation and level of diversity (estimated with Nei index) across evolution in a combined on farm and on station experimentation. The results showed that the varieties evolved and even adapted over 2 generations only (especially on maturity traits) but conserved their identity (no evolution of ear morphological traits). They all conserved their diversity, which demonstrated the pertinence of farmers’ selection (it is not a bottleneck). These results suggested that the genetically heterogeneous nature of OPVs is an asset for farmers because they can adapt these varieties to specific local conditions and production objectives. Therefore, farmer OPVs should receive more support through social and regulatory recognition, as well as further interest from research