A Preliminary Study of Cold Tolerance in Maize Landraces.

Following maize domestication, several lineages differentiated into populations that were adapted to their local environments and/or identified by farmers as having distinct characteristics.  These populations are collectively known as landraces.  Maize landraces have a plethora of genetic diversity that may help today’s commercial hybrids adapt to challenging environmental conditions.  The objective of this study was to identify regional groups of landraces that had high levels of fitness when grown under cool conditions in a growth chamber.  While fitness (i.e., reproduction) could not be measured directly due to space limitations, we measured plant height as a proxy for fitness over several weeks following germination.  There was no clear difference in height the first couple weeks, but by week four two regions of landraces stood out.  These were landraces from the United States Southwest and the Andes.  Should certain landraces show evidence of cold tolerance, these may be good resources for crop improvement assuming their cold tolerance alleles did not pass through the bottleneck of selection to conventional varieties.  Identification of cold tolerance is also an important starting point for isolating genes underlying this trait.