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
8,801 maize seed samples were supplied in response to 300 requests. 108 requests were received from 24 foreign countries. 5.7 acres of nursery were grown last summer. Warm temperatures and low plant stress following planting resulted in an earlier than normal pollination season and excellent yields. Plantings were made of donated stocks (Hi27 near-isogenic mutant lines, plant and kernel color lines, rgd2-R, elm1-ref, phyB1, and phyB2 lines, a1-eap, meiotic mutants, various r1 and ga2 alleles, thi2-blk1, and others). Stocks produced from the project "Regulation of Maize Inflorescence Architecture" were grown this past summer. Approximately 300 families of M2 materials were grown to increase seed supplies and recover previously observed mutations. Also, 1,306 families M2 ethyl-methanesulfonate (EMS) treated materials were grown for adult plant observation. There are also additional sequence indexed lines from the UniformMu project. Our curation tools were updated and improved. 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. Maintenance continues on our web site. The new greenhouse space in Urbana was used for our fourth winter crop.
1. Further characterization of new corn mutants. It is useful to determine if traits of these mutants are due to defects in known genes or if they are novel traits. We conducted tests on several categories of mutants with similar effects on the corn plant and/or found to be located in a similar position on a chromosome. We identified additional mutant variants of four genes (lazy plant1, indeterminate growth1, viviparous kernel9, and etched kernel1). In this manner, we hope to incorporate more stocks from our vast collection of uncharacterized (phenotype-only) mutants into the main collection of characterized mutants. This will enhance corn biological research and lead to agronomic improvements in this crop plant.
2. Identification of a marker useful for selecting maize haploids (contains half the normal number of chromosomes; a doubled-haploid is a much more efficient way to create new inbred lines). We have characterized dominant yellow-green corn seedling/plant mutants. Most were found to be lethal as homozygotes (when made true-breeding), but one was completely viable and expresses well in both early seedlings and adult plants and would be easily scorable in selecting for haploids. The dominant yellow-green gene will be of interest in understanding plant metabolism (e.g., photosynthesis). Its use in haploid selection will allow more efficient breeding to develop new inbred lines. This will enhance corn biological and agricultural research by giving us a greater understanding metabolism and useful tools to enhance breeding.