2013 Annual Report
1a.Objectives (from AD-416):
The long term objective of this project is to diversify the genetic base of maize in the United States by the addition of new genes from exotic maize that will improve agronomic productivity, disease resistance, and insect resistance, and contribute value-added grain characteristics, including total extractable starch to support ethanol production.
1b.Approach (from AD-416):
Manage Germplasm Enhancement of Maize (GEM) field nurseries, seed inventories, and germplasm exchange so that new sources of germplasm and information reach stakeholders annually. With the GEM Project Technical Steering Group (TSG), identify and acquire new sources of exotic maize germplasm for breeding and diversity assessment projects. Conduct cooperative maize germplasm evaluations for host-plant resistance to gray leaf spot, southern corn leaf blight, northern leaf blight, and fumonisin production. Develop advanced maize breeding families, derived from non-U.S. and U.S. sources which are selected for wide adaptation to U.S. conditions.
This project has been replaced by new project #6645-21000-030-00D Broadening the Genetic Base of U.S. Maize with Genes from Unadapted Germplasm.
Yield trial data from the summer of 2012 was evaluated and selections were made for advancement to the 2013 yield trials. One hundred and twenty-seven of 400 entries tested in first year trials, and sixteen entries of sixty-four tested second year trials during the 2012 growing season were advanced to trials in 2013. 760 nursery rows were grown in the winter in Homestead, FL, including one hundred and forty rows for the allelic diversity project.
Evaluated and recommended exotic and semi-exotic germplasm for use by GEM cooperators. Genetic diversity in United States maize breeding programs is limited by use of a very limited base of maize germplasm that is derived primarily from the race “Corn Belt Dent”, only one of the 200-300 recognized races of maize. ARS researchers in Raleigh, N.C. evaluated a large number of semi-exotic breeding crosses (mostly 50% tropical and 50% temperate) and recommended several as promising sources of genetic diversity for breeding programs. Based on one year evaluations of breeding crosses, some of the most promising are 89291:S(NC368), 89291:N(LH51), 89291:N(LH59), 89291:N(PHG47), 90113:S(NK794), ATL100:S(NK794), BR105:S(DJ7), BR105:N(GEMN-0097), BR106:N(GEMN-0097), BR106:T33aS(DJ7), BR51039:N15, BR51039:S15, BR51501:N11a, BR51501:S11a, BR52051:S172641, CML287:S(DJ7), CML343:N(NC320), CML343:S(NS701), CML343:S(PHW52), CML287:GEMN-0155, FS8A(S):S092603, Ki43: S(DJ7), PASCO14:S212603, PASCO14:S212612, and TZI8:S(DJ7). Over the course of this project we have also evaluated exotic germplasm for use in development of new breeding crosses and identified several promising sources, including inbreds from the International Center for the Improvement of Maize and Wheat (CIMMYT; e.g., CML343, CML373, La Posta Sequia C7_F71-1-1-1-2-B-B-B) and the International Institute for Tropical Agriculture (IITA; e.g., TZI8 and 89291).ARS researchers in Raleigh, N.C. developed and recommended four germplasm lines to the GEM cooperators in FY13 for use in their breeding program, including BR52051:N11c-015-004 (now GEMN-0242), CML287:S15-024-003 (now GEMS-0243), CML287:S15-027-001 (now GEMS-0244), and DK888:S11b-037-018-008 (now GEMS-0245). Overall during the life of the project twenty-two germplasm lines were recommended to the GEM cooperators, all of which were derived from exotic sources and have acceptable yield and improved disease resistance as compared with standard commercial varieties.