Location: Corn Insects and Crop Genetics Research
2019 Annual Report
Objectives
Objective 1: Develop improved maize phenotyping methods based on process-based crop growth models and high throughput phenotyping methods.
Subobjective 1.1: Develop and validate crop growth model calibrations for diverse maize hybrids to predict maize hybrid performance across diverse environments.
Subobjective 1.2: Evaluate high throughput biochemical and metabolic assays for calibration of crop growth models and prediction of maize grain yield.
Subobjective 1.3: Evaluate remote sensing approaches for improving prediction of maize performance and crop growth model calibration.
Objective 2: Understand the molecular genetic control of gametophytic incompatibility.
Subobjective 2.1: Determine if ZmPme3 complements the ga1 allele to restore the female function of Ga1-s.
Subobjective 2.2: Determine the biochemical mechanism of pollen exclusion by the Ga1 system using E. coli expressed ZmPME3.
Subobjective 2.3: Identify binding partners of ZmPME3.
Approach
In order to used 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 to 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.
Progress Report
We made progress on all objectives of our project plan. Accurate crop growth models will allow researchers to predict crop performance, however current crop growth models are based on limited data. We collected data that will be used to improve crop growth models, enabling more accurate predictions of crop performance. We tested the hypothesis that ZmPME3 is responsible for the female function of the Ga1 locus by transforming ga1/ga1 maize plants with the ZmPME3 gene. These plants were planted in the greenhouse in winter 2019 and in the field in spring of 2019 and will be tested for the presence of the female function this summer. In addition, we developed constructs for production of ZmPME3 in E. coli.
The process of fertilization is required to produce grain in corn. It is controlled in part by gametophytic incompatibility. We and others have identified specific genes that control gametophytic incompatibility. In order to better understand how the components of the system work, we tested them in different varieties of corn. In addition, we produced one component in E. coli so we can more easily study the effects of modifications.
Gametophytic incompatibility systems can be used to control unwanted pollination. The value of organic sweet corn is reduced by cross pollination with dent corn. For the competitive grant entitled “Novel Strategies for Development of Field and Sweet Corn Varieties for Organic Producers” we advanced and evaluated crosses of sweet corn lines with lines carrying a gametophytic incompatibility system to reduce unwanted pollinations. We also developed improved molecular markers for gametophytic incompatibility systems.
We carried out activities required to meet the objectives of the NIFA-OREI funded extramural agreement “Breeding Corn for Organic Production Systems”. One objective of this project was to develop corn inbred lines optimized for poultry nutrition by including high levels of the essential nutrient, methionine. We finished data collection for an evaluation of high methionine doubled haploid inbred lines. We will select the best lines in this study for release. These lines will address the need of organic poultry producers for corn varieties designed for production of organic poultry feed.
Cover crops are beneficial to soil health in agronomic systems, however little is known about how cover crops interact with the other crops in the rotation. One of the objectives of the congressionally mandated agreement “Improving Organic Maize Production in the Northern Corn Belt” is to develop improved cropping systems that include cover crops. To this end, we produced seed for a study of the impact of corn canopy architecture on cover crops.
We carried out field evaluations for the Genomes 2 Fields project and assisted with the transition of the seed handling operation from our location to the University of Wisconsin to meet the objectives of the extramurally funded project “Analysis of Genotype by Environment Interaction in Diverse Maize Hybrids” (see accomplishment).
Accomplishments
1. Predicting how different crop cultivars will respond to varying environmental, weather, and management conditions remains a significant challenge in agriculture. Producers choose cultivars based on past performance in performance trials but do not have precise predictions of how a group of cultivars might be expected to perform on their farms. Researchers at Ames, Iowa, through participation in the Genomes to Fields Initiative, have helped to coordinate a large scale study of hundreds of corn hybrids grown in environments through the U.S. and Canada. The result of this collaboration with researchers across the U.S. is a large data set including hybrid performance data, genomic fingerprints on hybrids evaluated, and associated weather and management data. Experiments have been conducted since 2014. Two years after completion of each trial, data are released for public use. These data sets provide the largest public resource available for study of differential corn hybrid performance across many environments and will provide researchers in universities, companies and other organizations an avenue for studying new approaches to this difficult problem.
Review Publications
Lappe, R.R., Baier, J.W., Boehlein, S.K., Huffman, R., Qiaohui, L., Settles, M.A., Hannah, C.L., Stewart, J.D., Scott, M.P., Myers, A.M., Hennen-Bierwagen, T.A. 2017. Functions of maize genes encoding pyruvate phosphate dikinase in developing endosperm. Proceedings of the National Academy of Sciences. 115(1):E24-E33. https://doi.org/10.1073/pnas.1715668115.
Khamphasan, P., Lomthaisong, K., Harakotr, B., Ketthaisong, D., Willcox, M., Scott, M.P., Lertrat, K., Suriharn, B. 2018. Genotypic variation in anthocyanins, phenolic compounds and antioxidant activity in cob and husk of purple field corn. Agronomy Journal. 8(11):271. https://doi.org/10.3390/agronomy8110271.
Duangpapeng, P., Ketthaisong, D., Lomthaisong, K., Lertra, K., Willcox, M., Scott, M.P. 2018. Corn tassel: A new source of phytochemicals and antioxidants for value-added products in agro-industry. Agronomy Journal. 8:242. http://dx.doi.org/10.20944/preprints201809.0517.v1.
Gage, J.L., White, M.R., Edwards, J.W., Kaeppler, S., de Leon, N. 2018. Selection signatures underlying dramatic male inflorescence transformation during modern hybrid maize breeding. Genetics. 210(3):1125-1138. https://doi.org/10.1534/genetics.118.301487.
Vanous, A., Gardner, C.A., Blanco, M., Martin-Schwarze, A., Wang, J., Li, X., Lipka, A.E., Flint Garcia, S.A., Bohn, M., Edwards, J.W., Lübberstedt, T. 2018. Stability analysis of kernel quality traits in exotic-derived doubled haploid maize lines. The Plant Genome. 12(1). https://doi.org/10.3835/plantgenome2017.12.0114.
Kohlhase, D.R., Edwards, J.W., Owen, M. 2018. Inheritance of 4-hydroxyphenylpyruvate dioxygenase inhibitor herbicide resistance in an Amaranthus tuberculatus population from Iowa, USA. Plant Science. 274:360-368. https://doi.org/10.1016/j.plantsci.2018.06.004.
