Maize Germplasm Base-broadening and Breeding

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
201	1510	1080	10%
201	1510	1160	10%
202	1510	1080	10%
202	1510	1160	10%
206	1510	1080	10%
206	1510	1160	10%
212	1510	1080	10%
212	1510	1160	10%
712	1510	1080	10%
712	1510	1160	10%

Progress 10/01/06 to 09/30/12

Outputs
OUTPUTS: About 5,000 newly developed inbred lines were tested in topcross yield trials. In addition, yield trials were conducted to evaluate Ga1-s and Tcb1 hybrids. Four Mexican accessions were evaluated for the presence of dominant gametophytic factors. Several hundred experimental and released inbreds were tested for both Ga1-s and Ga1-m. Several hundred exotic inbreds were evaluated in topcross hybrids. Over 2,000 inbreds and topcrosses, along with several hundred commercial hybrds were evaluated for gray leaf spot resistance. PARTICIPANTS: Matt Krakowsky, Oliver Ott, Jill Recker, Paul Nelson, Mike Jines, Jim Holland, and Jesus Sanchez of the University of Guadalajara. Graduate training for Ott, Ricker, Jines, and Nelson. Long term research collaboration with Sanchez. TARGET AUDIENCES: Public and private corn breeders and corn pathologists; geneticists interested in maize isolating factors PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Thirteen inbred lines were released. GLS ratings of all commercial hybrids tested were presented to public and private breeders and to the Corn Growers Association of NC. The impact of Ga1-m on hybrids containing Ga1-s isolating mechanisms has been emphasized at national meetings of organic corn growers and to the USDA. NC inbreds are generally unrelated to current commercial inbreds and are aimed at broadening the germplasm base of commercial corn breeding. An essentially complete survey of all then-available ex-PVP lines and all NC State lines from NC250 to NC522 has been completed and is in process of being published.

Publications

van Heerwaarden, J., J. Doebley, W.H. Briggs, J.C. Glaubitz, M.M. Goodman, J.J. Sanchez G, and J. Ross-Ibarra. 2011. Genetic signals of origin, spread, and introgression in a large sample of maize landraces. PNAS 108:1088-1092.
Wendel, J.F. and M.M. Goodman. 2011. Stanley George Stephens, A Biographical Memoir. http://www.nasonline.org/publications/biographical-memoirs/memoir-pdf s/stephens-stanley.pdf
Sanchez, J. Jesus, Jose Miguel Padilla, Lino De la Cruz, Jose Ron, James Holland, Matthew Krakowsky, and Major Goodman. 2011. Use of gametophytic isolating mechanisms for maize. Plant Breeding News 230: 1.14 www.fao.org/ag/AGP/AGPC/doc/services/pbn/pbn-230.htm
Goldstein, W.A., W. Schmidt, H. Burger, M. Messmer, L.M. Pollak, M.E. Smith, M.M. Goodman, F.J. Kutka, and R.C. Prat. 2012. Chapter 10 Maize: Breeding and Field Testing for Organic Farmers. Pg. 175-189 in E.T. Lammerts van Bueren, J.R. Myers, Eds., Organic Crop Breeding, Wiley-Blackwell. 312 pages.

Progress 10/01/10 to 09/30/11

Outputs
OUTPUTS: Twenty-six yield trials of NC breeding materials and ex-PVP lines were conducted, most at 5 locations in NC. Seventeen gray leaf spot trials were conducted, three for second- and third-year, 50%-tropical GEM topcross trials, five for GEM releases, four for third year NC and ex-PVP topcrosses, one for a wide range of inbred lines, one for commercial hybrids and three for comparing inbreds to topcrosses. Each of these was done at three locations, with three ratings per location. Approximately 1,200 summer nursery plots were used for line advancement, with another 500 used for paired rows, about evenly split between new breeding crosses and making seed for next year's yield trials. About 150 summer rows were devoted to studies of gametophyte alleles, their states and distributions among NC released and experimental lines. 760 winter nursery plots were about split between topcrosses for yield trials (about 30%) and advancement or creation of new breeding crosses (about 70%). PARTICIPANTS: Technicians Wayne Dillard and William Hill provided technical support for the project. Dillard coordinated planting, harvesting, and pollinating work. Hill organized, randomized, and plotted the yield trials and also helped with planting, pollinating, and harvesting the nursery and isos. .Oliver Ott is a grad student who assisted with nursery pollination and harvest, did independent disease work, and helped with the GLS experiments. .Matt Krakowsky and Dale Dowden collaborated on nursery and yield trial organization, planting, and harvesting. Dowden organized our disease inoculations and helped score the gray leaf spot experiments. TARGET AUDIENCES: Written and oral reports were provided to the Corn Growers of North Carolina, the Weeds and Seeds group, and the GEM collaborators, at their annual meetings. Gametophyte results were reported to the organic corn growers group, with a written report published in late 2011. An invited paper summarizing our line development and testing results was presented at the annual Crop Science Society meetings. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Our topcross results with ex-PVP line evaluations have been widely used - relatively few of them are really competitive with current public or private lines. We have determined that a specific allele at the Ga1 locus, Ga1-m, which can defeat the isolating mechanism of Ga1-s, is found among NC line releases as well as many tropical sources. It will almost certainly undermine current efforts by organic breeders to use Ga1-s to prevent pollination by GMO corn. We began to evaluate hybrids containing a different gametophytic locus, Tcb1, that occurs rarely in maize and is not found among commercially-used materials. One newly tested Hawaii line has excellent GLS resistance and is a Stiff Salk line, and thus has the potential to greatly increase resistance to this important disease among female lines, where resistance is lacking. Correlations of GLS scores for a wide range of inbreds with their corresponding hybrids all exceeded 0.9, regardless of whether the hybrids used were resistant or susceptible to GLS.

Publications

van Heerwaarden , J., J. Doebley, W.H. Briggs, J.C. Glaubitz, M.M. Goodman, J.J. Sanchez G., and J. Ross-Ibarra. 2011. Genetic signals of origin, spread, and introgression in a large sample of maize landraces. Proc. Natl. Acad. Sci. 108:1088-1092.

Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: Twenty-five yield trials of NC breeding materials and ex-PVP lines were conducted, most at 5 locations in NC. Thirteen gray leaf spot trials were conducted, two for second- and third-year, 50%-tropical GEM topcross trials, two for GEM releases, two for third year NC and PVP topcrosses, one for experimental NC lines, one for newly-acquired tropical lines, one for PVP lines, one for commercial hybrids and three for comparing inbreds to topcrosses. With one exception, each of these was done at three locations, with two or three ratings per location. Approximately 1,300 summer nursery plots were used for line advancement, with another 700 used for paired rows, about evenly split between new breeding crosses and making seed for next year's yield trials. About 250 summer rows were devoted to studies of gametophyte alleles, their states and distributions among NC released and experimental lines. 760 winter nursery plots were about evenly split between topcrosses for yield trials and advancement or creation of new breeding crosses. PARTICIPANTS: Technicians Wayne Dillard and William Hill provided technical support for the project. Dillard coordinated planting, harvesting, and pollinating work. Hill organized, randomized, and plotted the yield trials and also helped with planting, pollinating, and harvesting the nursery and isos. Oliver Ott is a grad student who assisted with nursery pollination and harvest, did independent disease work, and helped plan his GLS experiments for 2010. Matt Krakowsky and Dale Dowden collaborated on nursery and yield trial organization, planting, and harvesting. Dowden organized our disease inoculations, helped score the gray leaf spot experiments, and helped Ott. TARGET AUDIENCES: Written and oral reports were provided to the Corn Growers of North Carolina and to the GEM collaborators, both at their annual meetings. Gametophyte results were reported to the organic corn growers group, with a written report under review that should be published in 2011. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Our topcross results with ex-PVP line evaluations have been widely used - relatively few of them are really competitive with current public or private lines. We have discovered that a specific allele at the Ga1 locus (Ga1-m, that exists in both US and Mexican breeding materials) that can defeat the isolating mechanism of Ga1-S and may eventually undermine current efforts by organic breeders to use Ga1-S to prevent pollination by GMO corn. As an alternative, we are beginning to develop lines with a different gametophytic locus, Tcb1, that occurs rarely in maize and is not found among commercially-used materials. One newly tested GEM line has excellent GLS resistance and is a Stiff Salk line; it thus has the potential to greatly increase resistance to this important disease among female lines, where resistance is lacking. One experimental line, 1274-1, has the greatest resistance we have seen to fusarium. By correlating GLS results between inbreds and hybrids, it has been possible to identify lines that carry dominant resistance to the disease as well as identify a few lines that have inconsistent results across resistant and susceptible testers. Yield trials of topcrosses of the TROPHY Elite synthetic again surprised us; 20% of the topcrosses in several experiments out-yielded the best check by at least 5 bu/a. Similar results occurred in 2008 in a single experiment, but we regarded them then as a either a set of "one year wonders" or a single set of poorly-performing checks. We will retest, but the results appear to be real, if unexpected.

Publications

van Heerwaardena , J., J. Doebley, W.H. Briggs, J.C. Glaubitz, M.M. Goodman, J.J. Sanchez G., and J. Ross-Ibarra. 2010. Genetic signals of origin, spread, and introgression in a large sample of maize landraces. PNAS Early Edition www.pnas.org/cgi/doi/10.1073/pnas.1013011108

Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: Twenty yield trials of NC breeding materials and ex-PVP lines were conducted, most at 5 locations. Six gray leaf spot trials were conducted, two for second- and third-year, 50%-tropical GEM trials, one for GEM releases, one for experimental NC lines, one for newly-acquired tropical lines, and one for commercial hybrids. Each of these was done at three locations, with two ratings per location. Approximately 1,500 nursery plots were used for line advancement, with another 1,000 used for paired rows for making seed for next year's yield trials. Several hundred rows were devoted to studies of gametophyte alleles, their states and distributions among NC released and experimental lines. PARTICIPANTS: Technicians Wayne Dillard and William Hill provided technical support for the project. Dillard coordinated planting, harvesting, and pollinating work. Hill organized, randomized, and plotted the yield trials and also helped with planting, pollinating, and harvesting the nursery and isos. Oliver Ott is a new grad student who assisted with nursery pollination and harvest, did independent disease work, and helped plan some of his own experiments for 2010. Matt Krakowsky and Dale Dowden collaborated on nursery and yield trial organization, planting, and harvesting. Dowden organized our disease inoculations, helped score the gray leaf spot experiments and helped train Ott. TARGET AUDIENCES: Written and oral reports were provided to the Corn Growers of North Carolina and to the GEM collaborators, both at their annual meetings. Gametophyte results were reported to the organic corn growers group. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Six new inbred lines were recommended for release. Our results on ex-PVP line evaluations have been widely used - relatively few of them are really competitive with current public or private lines. We have discovered that a specific allele at the Ga1 locus (that exists in both US and Mexican breeding materials) can defeat the isolating mechanism of Ga1-S and may eventually undermine current efforts by organic breeders to use Ga1-S to prevent pollination by GMO corn. Several newly tested all-tropical lines have excellent GLS resistance and have the potential to greatly increase resistance to this important disease.

Publications

Buckler, E.S., Holland, J.B., Bradbury, P.J., Acharya, C. B., Brown, P.J., Browne, C., Ersoz, E., Flint-Garcia, S., Garcia, A., Glaubitz, J.C., Goodman, M.M., Harjes, C., Guill, K., Kroon, D.E., Larsson, S., Lepak, N.K., Li, H., Mitchell, S.E., Pressoir, G., Peiffer, J. A., Rosas, M.O., Rocheford, T.R., Romay, M.C., Romero, S., Salvo, S., Villeda, H.S., da Silva, H.S., Sun, Q., Tian, F., Upadyayula, N., Ware, D., Yates, H., Yu, J., Zhang, Z., Kresovich, S., McMullen M. D. 2009. The Genetic Architecture of Maize Flowering Time. Science 325: 714-718.
McMullen, M.D., Kresovich, S., Villeda, H. S., Bradbury, P., Li, H., Sun, Q., Flint-Garcia, S., Thornsberry, J., Acharya, C. B., Bottoms, C., Brown, P., Browne, C., Eller, M., Guill, K., Harjes, C., Kroon, D., Lepak, N., Mitchell, S. E., Peterson, B., Pressoir, G., Romero, S., Rosas, M. O., Salvo, S., Yates, H., Hanson. M., Jones, E., Smith,S., Glaubitz, J. C., Goodman, M., Ware, D., Holland, J. B., Buckler, E. S. 2009. Genetic Properties of the Maize Nested Association Mapping Population. Science 325: 737-740.
Vigouroux, Y., J.C. Glaubitz, Y. Matsuoka, M.M. Goodman, J. Sanchez, and J. Doebley. 2008. Population structure and genetic diversity of New World maize races assessed by DNA microsatellites. American Journal of Botany 95: 1240-1253.

Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Completed plan for the world-wide handling of maize germplasm in collaboration with CIMMYT and the Crop Diversity Trust. Completed first yieldtrials of a comprehensive set of tropical inbreds and found one standout: CML343. Completed second year yield trials for family based topcrosses of the southern GEM project, identifying about 20 families (of the hundred tested for a second year) at least agronomically competitive with the checks; completed screening yield trials of a new set of almost 1,000 GEM topcross families; made about 1,000 new topcrosses of GEM tropical x temperate populations; and developed additional S1 and S2 families. A set of foundation seed and Pioneer sister line crosses were tested to determine appropriateness for use as testers. PARTICIPANTS: P.T. Nelson completed much of his Ph.D. research during this period. Matt Krakowsky supervised much of the GEM work reported here. Pioneer provided SNIP data for the Nelson et al paper. TARGET AUDIENCES: Private and public corn breeders. Maize germplasm curators. Anyone concerned with narrowness of our germplasm base in corn or other crops. PROJECT MODIFICATIONS: Changed manner of recurrent selection from S1 per se performance to full-sib topcross testing on the basis of theory and data developed in Mike Jines' 2007 Ph.D. thesis. First data in from new procedure look very promising.

Impacts
Identified NC368 x NC320 as a potential biofuel source - has yielded more than the best hybrids from DeKalb and Pioneer for 4 straight years. After eliminating those ex-PVP lines which perform poorly per se (LH51, LH156, Seagull 17), only about 8 lines appear to have much promise out of the 100 plus ex-PVP lines that we have tested: DJ7, LH132, and NK794 (SS); LH60, LH150, PHG35, and PHN47 (NSS); DKHBA1 performs reasonably well in both directions. Several of the full-sib families tested from the TROPHY Elite recurrent selection project were competitive with the better checks (and much better than the broad-base tester that was used, LH334.LH354). Of 90 families tested, the lowest yield was 109 bu/A., five bushels higher than the tester. Our attempt to replace FR1064 x LH132 as a tester with LH244 x LH245, failed as the latter performs rather poorly in Florida, appears to add no great advantage in yield, standability or moisture compared to FR1064 x LH132, and is composed of quite closely related lines. LH283 x LH284 works well in both summer and winter nurseries and its crosses yield well, but its crosses lodge. Our preferred choices among these would be SS1 x SS2 and NSS3 x NSS4, both from Pioneer.

Publications

Nelson, P.T., N.D. Coles, J.B. Holland, D.M. Bubeck, S. Smith, and M.M. Goodman. 2008. Molecular characterization of maize inbreds with expired U.S. plant variety protection. Crop Sci. 48:1673-1685.
Nelson, P.T., and M.M. Goodman. 2008. Evaluation of elite exotic maize inbreds for use in temperate breeding. Crop Science 48:85-92.

Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: 49 gem entries (out of almost 500 tested) have been advanced from first year to second year trials in 2007, and 20 entries (out of 90 tested) were advanced from second year to third year testing. In 2007, 16,300 GEM yield and disease plots were coordinated through Raleigh (8,700 planted at NC State locations). This includes 400+ plots that were grown solely for GLS evaluations at three NC State locations. Approximately, 1250 GEM nursery rows and over 800 isolation block rows were planted in 2007 at Raleigh. Nursery work involves 12 new GEM breeding crosses. New tropical lines were evaluated in four trials. Over 300 nursery rows were devoted to the Allelic Diversity study, which involves accessions that are outside the core plant breeding materials utilized by GEM and most plant breeding organizations. These represent new F1 hybrids from about 75 accessions. The F1s were produced using PHB47 and PHZ51 as ex-PVP parents. Backcrosses to the ex-PVP lines were made this summer. Eight new testers are being evaluated (three from Holdens and five from Pioneer); these were evaluated in two trials. PARTICIPANTS: Provided training for P.T. Nelson, a Ph.D. candidate.

Impacts
In 2007, 11 GEM families were recommended to GEM Cooperators and provided from stocks furnished to Ames. We have identified new sources of tropical germplasm that in topcrosses are competitive with current hybrids. This will have a major impact on the GEM (Germplasm Enhancement of Maize) program, a public/private consortium that basically involves all corm breeding efforts in the country. CML343, an all-tropical inbred from CIMMYT is particularly impressive.

Publications

Balint-Kurti, P.J., Krakowsky, M. D., Jines, M. P., Robertson, L. A., Molnar, T. L., Goodman M. M. and Holland J. B. 2006. Identification of quantitative trait loci for resistance to Southern Leaf Blight and days to anthesis in a maize recombinant inbred line population. Phytopathology 96:1067-1071.
Carson, M.L., P. Balint-Kurti, M. Blanco, M. Millard, S. Duvick, R. Holley, J. Hyduncia, and M.M.Goodman. 2006. Registration of nine high-yielding tropical by temperate maize germplasm lines adapted for the Southern USA. Crop Science 46:1825-1826.
Goodman, M.M. 2006. Broadening the U.S. maize germplasm base. Maydica 50: 203-214.
Jines, M.P., P. Balint-Kurti, L.A. Robertson-Hoyt, T. Molnar, J.B. Holland, and M.M. Goodman. 2007. Mapping resistance to Southern rust in a tropical by temperate maize recombinant inbred topcross population. Theor. Appl. Genet. 114:659-667.
Nelson, P.T., M.P. Jines, and M.M. Goodman. 2006. Selecting among available, elite tropical maize inbreds for use in long-term temperate breeding. Maydica 51:255-262.
Sanchez G., J.J., M.M. Goodman, and C.W. Stuber. Racial diversity of maize in Brazil and adjacent areas. 2006. Maydica 52:13-30.
Taba, S. and M.M. Goodman. 2006. Development of a global strategy for the ex situ conservation of maize. CIMMYT, Mexico City. 56 p.

Progress 10/01/05 to 09/30/06

Outputs
56 GEM entries (out of 720 tested) have been advanced from first year to second year trials in 2006, and 58 entries (out of 134 tested) advanced from second year to third year testing. In 2006, 17,233 yield trial plots were coordinated through Raleigh (9,895 planted at NC State locations). An additional 972 plots were grown solely for GLS evaluations at three NC State locations; thus a total of 18,205 evaluation plots were coordinated through Raleigh. We have continued routine screening of available tropical lines, as so little data are available to choose among them; thus far the best lines are CML258, CML264, CML274, CML277, CML341, CML343, TZI8, and TZI9. Direct tests of Breeding Cross F1s were continued in 2006, and useful data was obtained for 3 locations. 11 GEM families have been identified for release to cooperators. After working with 50%-tropical GEM allelic diversity lines a second summer, it was apparent that survival to homozygosity of such materials was problematic in North Carolina. The likelihood of any surviving lines being used for phenotyping in the Midwest would clearly be very low. As a result, we recommended the use of earlier-maturing PVP lines with backcrossing.

Impacts
Lines released by NC State and associated germplasm-development activities have made NC State the leading U.S. institution for useful, new sources of corn germplasm. NC lines are especially noted for their disease resistance and stress tolerance.

Publications

Balint-Kurti, P., M. Blanco, M. Millard, S. Duvick, J. Holland, M. Clements, R. Holley, M.L. Carson, and M. M. Goodman. 2006. Release of 14 GEM Breeding Lines. Crop Science 46:996-998.
Hawbaker, M.S. and M.M. Goodman. 2006. Resistance of temperately adapted tropical inbred lines and testcrosses to three important maize diseases. Maydica 51: 135 - 139.
Carson, M.L., P. Balint-Kurti, M. Blanco, M. Millard, S. Duvick, R. Holley, J. Hyduncia, and M.M.Goodman. 2006. Registration of 9 high-yielding maize germplasms adapted for the southern US, derived from tropical by temperate crosses. Crop Science 46:1825-1826.
Buckler IV, E.S., M.M. Goodman, T.P. Holtsford, J.F. Doebley, and J. Sanchez G. 2006. Phylogeography of the wild subspecies of Zea mays. Maydica 51:123-134.
Sanchez G., J.J., M.M. Goodman, R. McK. Bird, and C.W. Stuber. 2006. Isozyme and morphological variation in maize of five Andean countries. Maydica 51:25-42.
Thompson, D.L., and M.M. Goodman. 2006. Increasing kernel density for two inbred lines of maize. Crop Science 46: 2179-2182. Zhao, W., P. Canaran, R. Jurkuta, T. Fulton, J. Glaubitz, E. Buckler, J. Doebley, B. Gaut, M. Goodman, J. Holland, S. Kresovich, M. McMullen, L. Stein, and D. Ware. 2006. Panzea: a database and resource for molecular and functional diversity in the maize genome. Nucl. Acids Res. 34: D752-757.

Progress 10/01/04 to 09/30/05

Outputs
Completed third-year yield trials for the seventh set of family-based topcrosses of the southern GEM project, identifying 27 families (of 216 that were tested for a second year) at least agronomically competitive with the checks; completed screening yield trials of a new set of over 1,000 GEM topcross families; made about 1,000 new topcrosses of selfed families in about 20 GEM tropical x temperate populations; and developed additional S1 and S2 families. A new set of potential foundation-seed, sister-line crosses were made for initial testing in 2006 to determine their appropriateness for use as testers in the GEM program. Released 31 GEM families through the North Central Plant Introduction Station. These families had performance at least equivalent to the commercial checks in three years of multi-location testing. Summarized an assessment of the world-wide SSR variation among public inbred lines and completed the deposition of sets of seed of these lines with the NCRPIS in Ames and with Ft. Collins. Released a set of 19 NC lines.

Impacts
The narrow genetic base of U.S. corn breeding is sufficiently limited that 20 private companies, including all major ones, have joined a private/public consortium in which N.C. State is the lead institution to develop alternative sources of breeding materials that are 50% tropical.

Publications

Flint-Garcia, S.A., A.-C. Thuillet, J.Yu, G. Pressoir, S.M. Romero, S.E. Mitchell, J. Doebley, S. Kresovich, M.M. Goodman, and E.S. Buckler. 2005. Maize association population: a high-resolution platform for quantitative trait locus dissection. The Plant Journal 44: 1054 -1064.
Goodman, M.M. 2004. Developing temperate inbreds using tropical maize germplasm: Rationale, results, conclusions. Maydica 49:209-220.
Goodman, M.M. and L.M. Garcia Barrios. 2004. Assessment of biological effects in agriculture in Mexico. Chapter 5 in Maize and Biodiversity: The Effects of Transgenic Maize in Mexico. Web publication: http://www.cec.org/maize/resources/chapters.cfm?varlan=english

Progress 10/01/03 to 09/30/04

Outputs
Completed third-year yield trials for the sixth set of family-based topcrosses of the southern GEM project, identifying 59 families (of about 100 that were tested for a second year) at least agronomically competitive with the checks; completed screening yield trials of a new set of over 1,100 GEM topcross families; made about 1,200 new topcrosses of selfed families in about 20 GEM tropical x temperate populations; and developed additional S1 and S2 families. A set of potential foundation-seed, sister-line crosses were made and tested in third-year experimental testcrosses to determine their appropriateness for use as testers in the GEM program; the survivors of earlier trials others were tested across NC and the Midwest in 2004. Collected additional yield-trial data on a set of 40 GEM S4 and S5 families deposited with the North Central Plant Introduction Station. These families had performance at least equivalent to the commercial checks in three years of multi-location testing. Summarized an assessment of the world-wide SSR variation among public inbred lines. Deposited sets of seed of these lines with the NCRPIS in Ames and with Ft. Collins. Deposited a set of all the extant typical accessions of the Latin American races of maize with the NCRPIS at Ames.

Impacts
The project (GEM, Germplasm Enhancement of Maize) represents the first and only industry-wide cooperative breeding effort. Seed requests from cooperators, about 75% private and 25% public, suggest that it is contributing to an expansion of the genetic base for US corn breeding.

Publications

Carson, M.L., M.M. Goodman, and S.M. Williamson. 2002. Variation in aggressiveness among isolates of Cercospora from maize as a potential cause of genotype-environment interaction in gray leaf spot trials. Plant Disease 86:1089-1093.
Goodman, M.M. 2004. Plant breeding requirements for applied molecular biology. Crop Sci. 44: 1913-1914.
Liu, K., M. M. Goodman, S. V. Muse, J. S. Smith, E. S. Buckler, and J. F. Doebley. 2003. Genetic structure and diversity among maize inbred lines as inferred from DNA microsatellites. Genetics 165:2117-2128.
Tarter, J.A., M.M. Goodman, and J.B. Holland. 2003. Testcross performance of semiexotic inbred lines derived from Latin American maize accessions. Crop Sci. 43:2272-2278.
Wilson, L.M., S. Rinehart-Whitt, A. M. Ibanez, T.R. Rocheford, M.M. Goodman and E.S Buckler, IV. 2004. Dissection of maize kernel composition and starch production by candidate gene association. Plant Cell:16: 2719-2733.

Progress 10/01/02 to 09/30/03

Outputs
Completed third-year yield trails evaluating choices of testers for choosing among new tropical germplasm sources. Completed third-year yield trials for the fifth set of family-based topcrosses of the southern GEM project, identifying 20 families (of about 150 that were tested for a second year) at least agronomically equivalent to the checks; completed screening yield trials of a new set of over 1,200 GEM topcross families; made about 1,200 new topcrosses of selfed families in about 20 GEM tropical x temperate populations; and developed additional S1 and S2 families. A new set of potential foundation-seed, sister-line crosses were made and tested in third-year experimental testcrosses to determine their appropriateness for use as testers in the GEM program; half were rejected, the others will be widely tested across NC and the Midwest this year. Collected additional yield-trial data on a set of 30 GEM S4 and S5 families deposited with the North Central Plant Introduction Station. These families had performance at least equivalent to the commercial checks in three years of multi-location testing on 3 to 4 testers. Some performed extremely well on several testers. Summarized a preliminary assessment of the world-wide SSR variation among public inbred lines.

Impacts
The project (GEM, Germplasm Enhancement of Maize) represents the first and only industry-wide cooperative breeding effort. Seed requests from cooperators, about 75% private and 25% public, suggest that it is contributing to an expansion of the genetic base for US corn breeding.

Publications

Matsuoka, Y., S. E. Mitchell, S. Kresovich, M. Goodman and J. Doebley. 2002. Microsatellites in Zea - variability, patterns of mutations, and use for evolutionary studies. Theor. Appl. Genet. 104:436-450.
Holland, J.B. and M.M. Goodman. 2003. Combining ability of a tropical-derived maize population with isogenic Bt and conventional testers. Maydica 48:1-8.
Lewis, R.S. and M.M. Goodman. 2003. Incorporation of tropical maize germplasm into inbred lines derived from temperate x temperate-adapted tropical line crosses: Agronomic and molecular assessment. Theor. Appl. Genet. 107: 798-805.

Progress 10/01/01 to 09/30/02

Outputs
Progress Report: Completed third-year yield trails of topcrosses of the lines derived from a 15 entry breeding diallel of mostly all-tropical, temperate adapted lines. Completed second-year yield trials for the fifth set of family-based topcrosses of the southern GEM project, identifying 14 families (of about 150 that were tested for a second year) at least agronomically equivalent to the checks; completed screening yield trials of a new set of over 1,100 GEM topcross families; made about 1,500 new topcrosses of selfed families in about 20 GEM tropical x temperate populations; and developed additional S1 and S2 families. Released a set of 17 new inbred lines. Identified a set of 12 new lines for eventual release. These lines should be well adapted to the southern U.S. and provide useful sources of new genetic variation within an acceptable range of yield, maturity, standability, and disease resistance. A new set of potential foundation-seed, sister-line crosses were made for testing in first year experimental testcrosses to determine their appropriateness for use as testers in the GEM program. Completed 2nd year testing of another set of potential testers. Increased a set of 14 new GEM families for deposit with the North Central Plant Introduction Station. These families had performance at least equivalent to the commercial checks in two years of multi-location testing on 2 or more testers. Completed an initial study of the genetic variation among a set of worldwide inbreds of maize based on SSR variation.

Impacts
The GEM (Germplasm Enhancement of Maize) project represents the first and only industry-wide cooperative breeding effort. It is clearly contributing to an expansion of the genetic base for US corn breeding.

Publications

Tallury, S.P. and M.M. Goodman. 2001. The state of the use of maize genetic diversity in the USA and sub-Saharan Africa. Pp. 159-180 in Cooper, H.D., C. Spillane, and T. Hodgkin (eds.), Broadening the Genetic Base of Crop Production. CAB Publishing, Wallingford, UK.
Goodman, Major M. 2002. New sources of germplasm: Lines, transgenes, and breeders. Pp. 28 - 41 in J.M. Martinez R., F. Rincon S, and G. Martinez G. (eds.), Mem. Congresso Nacional de Fitogenetica, Univ. Autonimo Agr. Antonio Narro, Saltillo, Coah., Mexico.
Matsuoka, Y., Y. Vigouroux, M. M. Goodman, J. Sanchez G., E. Buckler, and J. Doebley. 2002. A single domestication for maize shown by multilocus microsatellite genotyping. PNAS 99:6080-6084.

Progress 10/01/00 to 09/30/01

Outputs
Completed second-year yield trails of topcrosses of the lines derived from a 15 entry breeding diallel of mostly all-tropical, temperate adapted lines. Completed second-year yield trials for the fourth set of family-based topcrosses of the southern GEM project (with Marty Carson), identifying 17 families (of about 200 that were tested for a second year) at least agronomically equivalent to the checks; completed screening yield trials of a new set of over 1,200 GEM topcross families; made about 1,000 new topcrosses of selfed families in about 16 GEM tropical x temperate populations; and developed additional S1 and S2 families. Released a set of 12 new inbred lines. Identified a set of 16 new lines for eventual release. These lines should be well adapted to the southern U.S. and provide useful sources of new genetic variation within an acceptable range of yield, maturity, standability, and disease resistance. A new set of potential foundation-seed, sister-line crosses were made and tested in first year experimental testcrosses to determine their appropriateness for use as testers in the GEM program. Deposited seed of about 30 GEM S4 and S5 families with the North Central Plant Introduction Station for distribution. These families had performance at least equivalent to the commercial checks in two years of multi-location testing on 2 or more testers. Completed an overall description of the genetic variation of maize of the Americas based on SSR variation.

Impacts
The GEM (Germplasm Enhancement of Maize) project represents the first and only industry-wide cooperative breeding effort. Seed requests from cooperators, about 75% private and 25% public, suggest that it is contributing to an expansion of the genetic base for US corn breeding.

Publications

Herrera C., B.E., F. Castillo G., J.J. Sanchez G., R. Ortega P., and M.M. Goodman. 2000. Caracteres morfologicos para valorar la diversidad entre poblaciones de maiz en uma region. Rev. Fitotecnia Mexicana 23:335-355.
Remington, D.L, Thornsberry, J. Matsuoka, L. Wilson, S. Rhinehart-Whitt, J. Doebley, S. Kresovitch, M.M. Goodman, and E.S. Buckler IV. 2001. Structure of linkage disequilibrium and phenotypic associations in the maize genome. PNAS 98: 11479-11484.
Thornsberry, J. M., M. M. Goodman, J. Doebley, S. Kresovich, D. Nielsen, and E. S. Buckler, IV. 2001. Dwarf8 polymorphisms associate with variation in flowering time. Nature Genetics 28:286-289.