Agricultural and Forest Meteorology 148: 1598-1610, 2008.
Abstract There has been considerable speculation that increasing uprightness of leaves could lead to increased productivity. However, maize leaves are curved and we show that curvature varies between leaves on the same plant, between a hybrid released in 1991 (Pioneer 3394) compared with hybrids released in 1963 (Pioneer 3306) and 1936 (Pioneer 307), and between planting densities within hybrids. We found curvature could not be described by a single system of equations but used maximum leaf height and leaf tip:maximum leaf height ratio for making comparisons. We found no consistent relationships between differences in leaf curvature and measurements of leaf mid-rib morphology or anatomy. However, we found hybrid 3394 had shorter, more lanceolate leaves than the other two hybrids, and had a lower estimated torque around the point of leaf attachment to the stem. This hybrid also had a significantly smaller auricle base and smaller angle between the leaf blade and auricle base. We suggest that these features, combined with the lower torque, may be related to differences in leaf curvature.