Ethephon Alteration of Corn Plant Morphology

Abstract

AbstractReduction in lodging, and plant and ear height resulting from ethephon application to corn (Zea mays L.) has been reported, but no attempt has been made to determine the influence of ethephon on internode properties and lodging. The objective of this study was to determine the influence of time and rate of ethephon application on plant and ear height, and length, diameter, and weight length−1 of internodes of corn plants. Ethephon was applied at rates of 0.0, 0.14,0.28, and 0.56 kg ha−1 at tassel elongation (TE), 6 d after tassel elongation (TE+6), and at ear elongation (EE) to Pioneer hybrid P3183 grown on Sharpsburg silty clay loam soil (fine, montmorillonitic, mesic Typic Argiudoll). Plant and ear height were reduced more by ethephon application at EE than at TE or TE+6. Increasing ethephon application from 0.0 to 0.56 kg ha−1 at EE resulted in plant and ear height reductions from 237 to 174 cm and 132 to 93 cm, respectively. Ethephon application resulted in reduced length of internodes, whereas diameter and weight length−1 increased. When applied at TE, ethephon resulted in a maximum of 48 mm reduction in internode length, 2.5 mm increase in internode diameter, and 0.017 g mm−1 increase in weight length−1; whereas application at EE resulted in a maximum of 99 mm reduction in internode length, 2.1 mm increase in internode diameter, and 0.019 g mm−1 increase in weight length−1. Stalk lodging was positively correlated to the length of Internodes 11 through 15. Application of ethephon resulted in large changes in the stalk morphology of corn plants, many of which contribute to reduced stalk lodging. Harvestable grain yield either declined or remained constant with ethephon application. These data suggest that ethephon may prove to be a useful research tool, especially for studying stalk lodging and plant architecture.