Pollination Stress

Pollination Stress & Kernel Set in Corn

Asynchronous floral development and abortion of fertilized ovaries are responsible for most of the yield loss caused by drought during pollination of maize. Because silks remain receptive to pollen up to 7 days after they emerge from the husks, selection for genotypes that exsert silks in advance of pollen shed should be beneficial under dry conditions. Physiological studies have shown the increase in abortion in droughted plants results from a lack of assimilate production coupled with inhibition of carbohydrate metabolism within the female flowers. Examples of modern molecular approaches being used to identify the metabolic factors that might limit the delivery and utilization of sugars by the flowers and newly formed kernels will be discussed. Physiological studies also show that rapid and sustained ovary growth is critical to maximize kernel set. Therefore, agronomic practices that support rapid ovary growth rate at anthesis are essential for maintaining kernel set during drought.

Mark Westgate Professor of Crop Production and Physiology Agronomy
Iowa State Univ.
westgate@iastate.edu

Biography:  Dr. Mark E. Westgate is an Professor of Crop Production and Physiology Agronomy at Iowa State University. Dr. Westgate received his B.S. and M.S. degrees in Biology from the University of Dayton, in Dayton, Ohio. He obtained his Ph.D. degree in Agronomy from the University of Illinois, Urbana-Champaign in 1984. He came to ISU in 1998 after 15 years as Plant Physiologist with the USDA-Agricultural Research Service in Morris, MN. His research program at ISU investigates the physiological and molecular bases for variation in seed composition of soybeans. His research program on corn develops quantitative relationships of the flowering process to predict yield and extent of out-crossing due to pollen dispersal. Dr. Westgate also teaches several graduate courses in plant and crop physiology.