Location: Plant Introduction Research
Project Number: 5030-21000-065-000-D
Project Type: In-House Appropriated
Start Date: Feb 5, 2018
End Date: Feb 4, 2023
Objective:
Objective 1: Manage and coordinate the Midwestern component of a multi-year, multi-site, cooperative program of maize genetic resource evaluation, genetic enhancement, inbred line development, and information sharing which will broaden the genetic base for U.S. maize.
Sub-objectives: 1A. Coordinate and manage in-kind support for evaluation, development, and genetic enhancement of GEM germplasm.
1B. Manage GEM field nurseries, germplasm exchange, and seed inventories to ensure that new sources of germplasm and information reach stakeholders annually.
1C. Implement database evaluation enhancements to identify GEM lines best suited for particular uses.
Objective 2: Evaluate a wide diversity of temperate, subtropical, and tropical maize genetic resources for adaptation, yield, resistance to ear, stalk, and foliar diseases, tolerance to environmental extremes, and selected value-added, product quality traits. Record and disseminate evaluation data via the GEM database, GEM website, GRIN-Global and other data sources.
Sub-objectives: 2A. Evaluate 50-100 maize exotic breeding crosses and new sources of exotic germplasm annually for their adaptation to Midwestern U.S.; identify favorable agronomic traits; choose and prioritize germplasm for incorporation into breeding programs.
2B. With public and private-sector cooperators, evaluate maize germplasm for globally important leaf and stalk rot diseases, reduced ear mold and mycotoxin production, abiotic stress tolerance, host plant resistance to corn rootworm (CRW), multiple pest resistance for above ground insects, and key value-added traits such as highly digestible starch and resistant starch.
Objective 3: Breed and release maize populations and inbred lines with 25% subtropical-tropical/75% temperate pedigrees which contribute to U.S. maize more diverse genetic resistance to diseases, tolerance to environmental extremes, higher yield, unique product qualities, other valuable new traits, or which enable maize trait analysis and allelic diversity research.
Sub-objectives: 3A. Develop and release a novel set of “adapted” maize races resulting from the allelic diversity (AD) project as tools for gene discovery and genomic research.
3B. Develop and release germplasm with key traits, such as reduced mycotoxin level and biotic stress resistance. Disseminate germplasm information.
3C. Evaluate released lines to determine exotic genome contributions and identify unique disease and insect resistance genes.
Approach:
Obj 1: Extensive collaborations with the private, public and international sectors will be initiated to broaden the germplasm base and develop useful germplasm. ARS will serve as liaison for collaborators and the Technical Steering Group (TSG), selects germplasm, facilitates germplasm acquisition and stakeholder interactions, arranges for in-kind-support, information sharing, technology transfer in the form of new germplasm and associated information, and establishes and manages nurseries and yield trials. Multiple sites will serve nurseries, observations, crossing blocks, yield trials, and stress resistance evaluations. Companies participating in the collaboration will provide proprietary genetic resource crosses and information to facilitate their utilization. Input on sources of germplasm and their attributes, potential new collaborators, and research initiatives will be solicited from project participants and the TSG. Improved website reporting of agronomic and abiotic stress resistance information will be done.
Obj 2: Approximately 50-100 breeding crosses will be evaluated in multiple environments and ~30 selected annually for development in Ames or collaborator nurseries. Exotic maize breeding crosses and new sources of exotic germplasm will be evaluated for important leaf and stalk rot diseases, reduced ear mold and mycotoxin production, abiotic stress tolerance, and host plant resistance to corn rootworm and above ground insects. Trait evaluations will be conducted in favorable selection environments for traits of interest. Breeding material will be evaluated for value added traits related to grain quality. Evaluation data will be stored in the GEM database. Research findings are shared via the public GEM website and scientific publications.
Obj 3: Germplasm will be developed primarily from 25% tropical/75% temperate breeding crosses. Breeding crosses will also be developed from tropical landrace accesses or modern tropical inbreds crossed with elite temperate germplasm resources, from GEM x GEM releases, and other models to maximize useful exotic germplasm contributions. Agronomic performance testing will be done in house and collaboratively.
A dual line development track will release 1) conventionally derived lines which have been tested and selected for agronomic and/or stress tolerance traits, and 2) lines developed purely for the purpose of capturing allelic diversity (AD) from exotic donor genomes that do not undergo selection for agronomic or other traits. The AD project lines are to represent all of the nearly 300 landraces, with an average of 25% of their genome derived from exotic introgressions and 75% from a recurrent, US-adapted parent.
Following release, lines will be genotyped and molecular marker information provided to help identify useful genetics for disease and insect resistance genes. Two years post-release, conventionally derived lines will be deposited in the National Plant Germplasm System. Incorporation of the AD lines into the NPGS collection depends on their value, as determined by the research community. Research findings will guide criteria for their inclusion; many will be incorporated over time.
