Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/23/2003
Publication Date: 7/23/2003
Citation: Oneill, P.M., Shanahan, J.F., Caldwell, R.M. 2003. Use of chlorophyll fluorescence to characterize water and n stress response in maize hybrids. Agronomy Abstracts. #675817
Technical Abstract: The objective of this study was to evaluate agronomic and physiological responses of several corn hybrids differing in date of release (from early 1970's, early 1990's, and late 1990's) and other attributes to varying levels of irrigation and nitrogen (N) fertilizer. Treatments consisted of a factorial combination of 12 hybrids (11 Pioneer and B73 x Mo17), two irrigation levels (deficit and full), and two N levels (0 and 200 kg N ha-1) grown under field conditions during 1999-2002 seasons. Leaf greenness was monitored with a chlorophyll meter on several dates during reproductive growth and grain filling. A Walz PAM-2000 chlorophyll fluorometer was used to monitor leaf temperature, photosynthetic photon flux density and chlorophyll fluorescence (CF) on the same dates. Final grain yield and yield components were also determined. The hybrid produced in the 1970's yielded 0.4 Mg ha-1 more under N stress than the mean yields of hybrids released in the early and late 1990's. Under full N the mean yield of hybrids released in the late 1990's was 0.4 and 0.9 Mg ha-1 greater than hybrids of the early 1990's and 1970's, respectively. Hybrids also differed in their yield response to water treatments. Associations among leaf greenness, temperature and CF, and agronomic responses will also be discussed.