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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetics and Genomics of Complex Traits in Grain Crops

Location: Plant Genetics Research

Project Number: 5070-21000-038-00
Project Type: Appropriated

Start Date: Mar 26, 2013
End Date: Mar 25, 2018

Objective 1: Create novel genetic resources for complex trait dissection in diverse maize germplasm. • Sub-objective 1.1: Create, genotype, and phenotype doubled haploid (DH) lines from a synthetic population containing diverse germplasm, including teosinte alleles. • Sub-objective 1.2: Create, genotype and phenotype novel quantitative trait loci (QTL) populations derived from a (teosinte x B73) x B73 population. Objective 2: Characterize the genetic basis of important agronomic traits (heterosis, drought tolerance, yield components, DIMBOA synthesis, and kernel composition) in maize. • Sub-objective 2.1: Determine the genetic basis of heterosis and its relationship to recombination and the Hill-Robertson effect. • Sub-objective 2.2: Fine-map the regulatory site for the major QTL of DIMBOA synthesis for chromosome 4 from CI31A. • Sub-objective 2.3: Fine map the genes responsible for a KRN QTL on chromosome 2 in a teosinte x maize population. • Sub-objective 2.4: Determine the genetic basis of kernel composition in maize x teosinte introgression libraries, and compare the QTL and effects to those observed in maize. Objective 3: Determine molecular and biochemical mechanisms of drought tolerance in maize and model species. • Sub-objective 3.1: Determine the expression patterns of transcription factor (TF) genes in the drought response of maize. • Sub-objective 3.2: To fully characterize the molecular genetic basis of the conserved interplay between reactive oxygen species (ROS) and amino acid metabolism, linked through gamma-glutamyl amino acids (GGAA) metabolism and transport, and the role of GGAA metabolism in dehydration tolerance. Objective 4: Identify and curate key datasets that will serve to benchmark genomic discovery tools for key agronomic traits, especially response to biotic and abiotic environmental stressors. • Sub-objective 4.1: Bring into The Maize Genome Database (MaizeGDB) the phenotypic data generated by critically important research endeavors including the Maize Diversity Project. • Sub-objective 4.2: Curate maize metabolism and pathways data for release as a BioCyc database and as GO annotation files. Objective 5: Characterize the relationship between root biology and drought tolerance in wheat and related species. • Sub-objective 5.1: Elucidate the physiological basis of root growth responses in wheat (hard and soft red winter) and the “wheat model” Brachypodium distachyon, to imposed water deficits. Objective 6: Develop and improve sources of resistance in maize to corn rootworm larval feeding. Objective 7: Characterize Western corn rootworm colonies with resistance to Bacillus thuringiensis (Bt) toxins to facilitate better resistance management decisions.

Create and fully describe double haploid lines and QTL populations for complex trait dissection. Map and characterize yield QTLs to interrogate the genetic basis of heterosis in maize. Use QTL fine mapping protocols to define the genetic regulation of DIMBOA synthesis in maize. Develop targeted metabolomic profiles to define the role of nitrogen metabolism in establishing dehydration tolerance in the C4 grasses, including maize. Combine field experiments and transgenic maize lines to determine the role of selected transcription factors in the response of roots to water deficits and their possible role in drought tolerance. Use modern curation tools to improve the phenotype to gene utility of the MaizeGDB and improve linkages to other community database efforts.

Last Modified: 8/28/2016
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