Location: Corn Insects and Crop Genetics Research
Project Number: 5030-21000-073-000-D
Project Type: In-House Appropriated
Start Date: Mar 7, 2023
End Date: Mar 6, 2028
Objective:
Objective 1: Characterize the distribution of the Ga1 and Ga2 gametophytic incompatibility systems in U.S. maize breeding germplasm and the response to changes in temperature on their ability to exclude pollen.
Subobjective 1.A: Determine whether alleles capable of overcoming pollen exclusion barriers are present in the U.S. corn breeding germplasm.
Subobjective 1.B: Examine the effect of environmental factors on pollen exclusion systems.
Objective 2: Develop improved crop growth models using the Agricultural Production Systems Simulator (APSIM) for predicting variation in growth and yield among maize hybrids as affected by varying environmental and management conditions.
Subobjective 2.A: Calibrate APSIM to simulate development and growth of total dry matter, grain dry matter, and stalk dry matter across a range of multiple plant densities.
Subobjective 2.B: Test plasticity of maize sink during grain filling.
Approach:
In order to use hybrid-specific crop growth models to understand factors contributing to genotype by environment interactions, replicated field trials of hybrid corn varieties will be carried out and evaluated for morphological, phonological and chemical traits. Together with environmental data, these data will be used to develop crop growth models with publicly available software. Valuable measures of agronomic performance such as grain yield of the specific hybrids in the study will be predicted. These models will be validated using actual measurements of agronomic performance and used to predict performance in additional environmental conditions. In order to understand molecular genetic control mechanism of gametophytic incompatibility, we will construct a transgene encoding ZmPME3 and use it to complement the ga1 phenotype. A second transgene will be used to mutationally inactivate ZmPME3. All transgenic lines will be evaluated for their ability to exclude unwanted pollen in replicated field trials. In addition, ZmPME will be produced in a bacterial expression system and purified. The activity of the purified protein will be characterized using pectin methylesterase activity assays and the effect of this protein on pollen tube growth will be evaluated in vitro.
