Date of Award
Master of Science
Mark E. Westgate
Concerns about controlling pollen flow in maize ( Zea mays L.) have greatly increased since the introduction of transgenes for insect resistance, herbicide resistance, and production of pharmaceutical and industrial compounds. The primary concern is related to out-crossing with non-transgenic genotypes destined for food uses or organic production. Pollen control is necessary to prevent the introduction of transgenes into sexually compatible crops or wild relatives in locations where these are grown or occur naturally (e.g., Native maize genotypes in Mexico).;The central hypothesis of this dissertation is that out-crossing resulting from pollen flow in maize is a predictable process, which can be simulated and quantified. The thesis is organized into three chapters. Chapter 2 describes a field study to test how a natural vegetative wind barrier might be used to limit pollen dispersal. In 10 independent tests, diminishing wind speed across the maize canopy resulted in a smaller pattern of pollen dispersal in the surrounding field. Chapter 3 presents the first attempt to predict out-crossing in a commercial hybrid seed production field. The analysis demonstrates that out-crossing can be predicted accurately based on inbred flowering dynamics and estimates of pollen dispersal. The field study presented in Chapter 4 tests the potential for predicting the spatial pattern of out-crossing from a transgenic pollen source. The results demonstrate the accuracy of the combined kernel set and pollen dispersal models as well as the benefit of surrounding the transgenic source with a non-transgenic maize crop producing abundant pollen.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Juan Pablo Astini
Astini, Juan Pablo, "Managing maize pollen dispersal and out-crossing" (2007). Retrospective Theses and Dissertations. 14531.