© 2000 Kluwer Academic Publishers. Printed in the Netherlands. 25 Farmers ’ seed selection practices and traditional maize varieties in

Experimental results and farmer surveys from a Mexican community located in the buffer zone of a biosphere reserve indicate that farmers ’ seed selection practices protect the phenological integrity of their traditional maize varieties as they define them, despite numerous factors contributing to genetic instability. Analysis of morpho-logical and genetic data suggests that when subjected to significant gene flow through cross-pollination, ear characteristics are maintained through farmers ’ selection even though other characteristics may continue to evolve. Because the effects of farmers ’ selection practices are confined largely to ear characteristics, their practices appear to offer only limited scope for variety improvement. Farmers ’ expectations of what they can achieve through seed selection are similarly limited. These findings suggest complementary roles for professional breeders and Mexican farmers in enhancing mass selection methods to improve maize landraces on farms – if farmers themselves perceive benefits from the collaboration