|Avendano-Lopez, Adriana -|
|Sanchez-Gonzales, Jose -|
|Ruiz-Corral, Jose -|
|DE La Cruz-Larios, Lino -|
|Santacruz-Rubalcava, Fernando -|
|Sanchez Hernandez, Carla -|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 22, 2011
Publication Date: September 1, 2011
Citation: Avendano-Lopez, A., Sanchez-Gonzales, J., Ruiz-Corral, J., De La Cruz-Larios, L., Santacruz-Rubalcava, F., Sanchez Hernandez, C., Holland, J.B. 2011. Seed dormancy in Mexican teosinte. Crop Science. 51:2056-2066. Interpretive Summary: Teosinte is the closest wild relative of maize and may be a source of useful genes for domesticated corn. It grows wild in Mexico across many diverse ecological zones. To better understand the relationship between genetic variation and ecological adaptation, we studied the seed dormancy of a wide sample of teosintes from many different ecological zones of Mexico. Seed dormancy is an important factor in how the plants adapt to different environments: rapid germination without dormancy is advantageous in environments with sufficient rainfall, whereas seed dormancy that prevents germination until a certain length of time has passed is advantageous in environments with limited rainfall restricted to specific seasons. We found that seed dormancy in teosinte populations was highly related to geographic origin and climate of the region in which the seed was collected, as predicted by this hypothesis.
Technical Abstract: Seed dormancy in wild Zea species may affect fitness and relate to ecological adaptation. The primary objective of this study was to characterize the variation in seed germination of the wild species of the genus Zea that currently grow in Mexico, and to relate this variation to their ecological zones of adaptation. In addition, we compared methods to break dormancy and measured the germination responses of seeds to environment factors that are related to seasonal changes. Teosinte populations representing all the racial groups known in Mexico were collected during the period 2003 to 2008 in nine states of Mexico. Seed dormancy was classified according to rate loss (depth of dormancy). Results indicated that more than 90% of populations studied had some degree of seed dormancy. Non-dormant populations are distributed predominantly in semi-cold areas, while deep and very-deep seed dormancy was found in populations distributed in hot and very hot environments in well defined geographic regions of the River Balsas Basin and in San Felipe Usila, Oaxaca. Mechanical seed scarification was the best method to break dormancy.