The map of the USA shows: (IMAGE) University of Bonn Caption The drier the region, the fewer seminal roots the maize varieties cultivated there had on average (black figure; the pie chart shows the proportion of varieties with up to one seminal root in yellow, with up to three seminal roots in green and with more than three seminal roots in blue). Credit Image: AG Hochholdinger/University of Bonn Usage Restrictions This image may be used together with the press release. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.