1a. Objectives (from AD-416)
1) Efficiently and effectively conserve and distribute a comprehensive assemblage of maize genetic stocks and associated information to maize researchers and breeders worldwide. 2) Strategically genotype and phenotype maize genetic stocks for priority traits, and incorporate genotypic and phenotypic data into MaizeGDB, GRIN, and/or other databases.
1b. Approach (from AD-416)
Our mission is to make natural and induced allelic and chromosomal variations available to the scientific community and to make information about the mutant collection available to researchers. The National Plant Germplasm System provides support to selected genetic stock centers having genetic resources of value to U.S. agricultural interests. The Maize Genetics Cooperation - Stock Center maintains important accessions of morphological and physiological markers, aneuploid material, translocations and inversions that are important tools in biological research. This project will increase the value of the stock collection as genetic tools and confirm the status of novel mutants discovered. Maize mutants have historically been used in gene discovery and will continue to be used in this way. New mapping tools in our collection will allow easier identification of genomic sequence underlying a phenotype. More recently, novel genes are being identified purely by sequence analyses. This will excel in the next few years with the release of the maize genome sequence. Identification of the functions for these newly identified genes can be determined by researchers with reverse genetics resources in our collection.
3. Progress Report
32,112 seed samples were supplied in response to 277 requests. 76 requests were received from 23 foreign countries. 7.2 acres of nursery were grown last summer. Moderate temperatures and low plant stress during and following pollination resulted in excellent yields. Two acres were devoted to the propagation of the large collection of cytological variants, including A A translocation stocks and inversions. Additional translocations marked with wx1 were checked with linkage tests to confirm the chromosome arms involved. Stocks produced from the project "Regulation of Maize Inflorescence Architecture" were grown this past summer. Approximately 250 families of M2 materials were grown to increase seed supplies and recover previously observed mutations. Also, 1553 families M2 EMS materials were grown for adult plant observation. Visitors from 5 different institutes walked these fields and found many new mutant phenotypes that will be added to the project database. We have received close to 5000 of the Nested Association Mapping Recombinant Inbred Lines (NAM RILs), from the Molecular and Functional Diversity of the Maize Genome project. There are also additional lines from the Functional Genomics of Maize Chromatin project. The Maize TILLING Project has also donated an additional 1712 lines to our current holdings. Our curation tools were updated. These tools input our public stock data directly into MaizeGDB to give maize scientists access to up-to-date information about our collection. The tools are also used for our internal database. A new pedigree-entry tool was developed that reduced pedigree data entry time significantly and other tools were rewritten or written from scratch to import many years of unentered pedigree information. A tool to generate field notes conveniently and easily was created. Our web site and all other services have been migrated to a new hardware/software arrangement, which is much more reliable and faster than the old setup. Maintenance continues on our web site. More than 2000 phenotype–only stocks were sent to the National Center for Genetic Resources Preservation in Fort Collins, Colorado for back-up. Selected samples from the main collection were also pulled and sent this year. Our new inventory system has made selecting ears to be sent and producing a packing list to accompany them a much more efficient procedure. We did not grow a winter crop this year. Critical plantings of a few lines were made in the greenhouse, but the lack of a field grown winter crop represents a set-back to our program, not only because of the loss of a nursery generation, but also because it is easier to transfer mutations out of tropical backgrounds into Midwest adapted backgrounds. The new greenhouse space in Urbana was used for our third winter crop. The space has proven to be excellent for growing material that doesn’t do well under our field conditions. We finally have enough storage drawers to unpack and organize the approximately 36,000 Maize Targeted Mutagenesis lines we have held in boxes in the aisles of our storage rooms.
1. Characterization of stocks by allele testing. This is useful to determine if traits of uncharacterized stocks are allelic to known genes, or if they are novel traits. We conducted allelism tests of several categories of mutants with similar phenotype or chromosome location. We identified additional alleles of pink scutelum1, viviparous5, lazy1, chlorophyll1, white3, and pale yellow9. This summer, we are testing additional members of the viviparous and pale endosperm classes of mutants. In this manner, we hope to incorporate more stocks from our vast collection of unplaced uncharacterized mutants into the main collection. This will enhance maize biological research and lead to agronomic improvements in this crop plant.
2. Further characterization of the Fcu system of r1 aleurone color enhancers. We further characterized the Enr (Fcu) system of r1 aleurone color enhancers and published a paper on the results. In order to further analyze this gene, we are attempting to tag Enr1 using one of the transposed Ac lines. We are collecting and characterizing additional alleles of Enr1 and other r1 aleurone color enhancers and inhibitors. This will enhance maize biological research by giving us a greater understanding of gene regulation.
Sachs M.M. 2009. Maize Genetic Resources. In: Kriz, A.L., Larkins, B.A. editors. Biotechnology in Agriculture and Forestry. Molecular Genetic Approaches to Maize Improvement. Volume 63. Berlin: Springer-Verlag. p. 197-209.