Distribution of sugar and soluble solids in the maize stalk

Limited worldwide energy sources have encouraged the search for energy alternatives such as stalk sugar in maize, L. Information on the distribution and amount of sugars and soluble solids found in maize stalks will be important if the maize plant is to be exploited for its total energy production. The objective of this study was to determine the distribution of soluble solids in the stalks of three maize hybrids. Three field plantings of five replicates were made at 4-wk intervals in 1981,1982, and 1983. Juice was sampled from each of the first ten internodes of two plants from each plot and a Brix reading taken by hand-held refractometer. In 1983, internode samples from each node in each plot were bulked and analyzed for sugar content using High Performance Liquid Chromotography (HPLC). Significant variation for soluble solids occurred among years, hybrids, and nodes. An older hybrid, developed for the South, had stalks that tended to increase in soluble solids concentration from bottom to the top of the plant. Two more recently developed hybrids decreased in soluble solids concentration from soil level upward toward the ear node, but increased from the ear node upward. The change or difference in pattern of soluble solids gradients for the more recently developed hybrids was attributed in part to selection for increased resistance to stalk rot, which is positively correlated with sugar content.