Location: Soybean/maize Germplasm, Pathology, and Genetics Research
2019 Annual Report
Objectives
Objective 1: Efficiently and effectively acquire maize genetic stocks; maintain their safety, genetic integrity, health and viability; and distribute them and associated information worldwide.
Objective 2: Develop more effective genetic resources maintenance, evaluation, and characterization methods and apply them to priority maize genetic stocks. Record and disseminate evaluation and characterization data via GRIN-Global and other data sources.
Objective 3: With other NPGS genebanks and Crop Germplasm Committees, develop, update, document, and implement best management practices and Crop Vulnerability Statements for maize genetic stock and information management.
Approach
We will cooperate with members of the maize genetics research community who are involved in genomics research; especially those with projects that will generate new mutants, reverse genetics resources and mapping populations. These projects will provide both seed and information about their donated stocks. We are working with projects whose aim is to discover new genes in maize by tagging genes with transposable elements or by chemical mutagenesis and combining phenotypic and sequence analyses. We also are involved in cooperative efforts with other researchers who are generating new mutants that will be deposited in our collection. Along with screening these stocks for kernel, ear, and seedling mutants, we will continue to organize adult plant grow-outs and invite visitors to help us search for novel mature plant traits. Selected mutants felt to be unique and have continued importance will be incorporated into our core collection and maintained. We will phenotype maize genetic stocks to ensure their identity and trueness-to-type. These processes will be customized to address the challenges that emerge. We plan to conduct allelism tests with mutants in our collection that exhibit similar phenotypes. Those that turn out to be due to novel genes will be mapped to chromosomal location and characterized further. Some will be the focus of further genetic studies. We will continue computerizing the information concerning existing maize genetics stocks and have that information readily available to cooperators. During the last funding period, information about our newly available stocks was computerized and made accessible. We will continue to enter all existing data on our maize genetic stocks and about the stocks we will soon receive. Information about all stocks that are available upon request will be updated, as needed, in the Maize Genome Database. We will work with the Maize Crop Germplasm Committee to ensure that our best management practices are up-to-date. We will also work with the Maize Crop Germplasm Committee to ensure that the maize vulnerability statement is up-to-date.
Progress Report
9,151 maize seed samples were supplied in response to 458 requests. Approximately 4.0 acres of nursery were grown. Warm, dry spring weather allowed the planting of the first crossing nursery in a timely manner; however, two subsequent weeks of unusually wet and cold weather resulted in poor germination and poor stands in large parts of the first nursery. Excellent weather during the remainder of the growing season allowed for good germination in our crossing nurseries, as well as a normal pollination season; no supplemental irrigation was required, although we did irrigate our second crossing nursery to deter birds from pulling up seedlings through loose soil. There were sufficient stands for a good increase in almost all instances. Plantings were made of donated stocks. Approximately 250 families of new mutant materials were grown to increase seed supplies and recover previously observed mutations. Also, 1,070 families of new ethyl methanesulfonate induced mutant materials were grown for adult plant observation and 191 families were screened in sand benches for seedling traits. There are also additional sequence indexed lines from the Activator/Dissociation transposable element mutagenesis project. Curatorial tools developed specifically for the Maize Genetics Cooperation Stock Center were updated and improved. These tools input public stock data directly into MaizeGDB to give maize scientists access to up-to-date information about the collection. The tools are also used for an internal database. Maintenance continues on the Maize Genetics COOP web site.
Accomplishments
1. Identified new alleles at the shrunken6 and albescent1 loci in corn. Because it is now possible to edit plant genes to produce desired phenotypes, it is useful to determine if traits observed in new mutant lines result from defects in previously mutated genes, or if they represent mutations in previously uncharacterized genes. ARS researchers at Urbana, Illinois, conducted genetic tests on new corn mutants with similar effects on the corn plant and/or that were located close to previously mutated genes on corn chromosomes. The analysis identified additional mutant variants at the shrunken6 and albescent1 loci. Corn plants with shrunken6 mutations have shrunken kernels and pale green leaves, while albescent1 mutants have kernels with deep yellow endosperm in appropriate genetic backgrounds. Knowing which genes control beneficial traits will enhance corn biological research and lead to agronomic improvements in this crop plant, which lead to benefits to global food security and the economy.
