Brief Summary of Minutes of Annual Meeting

Illinois Agricultural Experimental Station
Submitted by Martin Bohn, Department of Crop Sciences University of Illinois, Champaign, IL

Faculty of the corn breeding and genetics group at the University of Illinois
- Martin O. Bohn
- Dick Johnson
- Rita H. Mumm (since 08-2008)
- Torbert R. Rocheford (joined Purdue faculty 08-2008)

Emeritus Faculty
- J.W. Dudley
- R. Lambert

Our Objectives
- Improve grain yield and value-added traits of corn.
- Improve agronomic characteristics of corn including resistance to disease and pests.
- Provide educational opportunities for students that prepare them for careers in plant breeding, genetics, and plant pathology.
- Provide continuing educational opportunities for commercial corn breeders.

Program Highlights
- The Illinois Plant Breeding Center was established (see http://plantbreeding.illinois.edu). Dr. Rita Mumm is the director of this new center.
- The Illinois Maize Breeding and Genetics Laboratory (IMBGL) organized the 44th Illinois Corn Breeders' School held in Champaign, Illinois, March 3-4, 2008. This CBS was attended by more than 200 corn breeders and geneticists from the public and private sector. Highlight of the CBS was an Open Forum and Panel discussion on 'How Public and Private Sector Can Effectively Work Together to Enhance Support for Maize Breeding and Genetics Education and Translational Research'. The CBS also featured a mini session on heterosis. More detailed information is available at the Illinois corn breeding and genetics laboratory (IMBGL) internet site (http://imbgl.cropsci.illinois.edu/index.html).
- Research results of the Illinois corn breeding and genetics group, including new findings on maize host plant resistance to western corn rootworm larvae feeding, maize root complexity, and cell wall composition, maize tassel and ear architecture, as well as kernel quality, including starch, protein, oil, and vitamin contents, were presented at several national and international conferences, including the 45th Illinois Corn Breeders' School (Champaign, IL, March 2008), Annual NCCC-167 Meeting (Baltimore, MD, March 2008), Maize Genetics Conference (Washington, DC, March 2008), DIABR-ACT- Harmonize the Strategies for Fighting Diabrotica virgifera virgifera (Goettingen, Germany, May 2008), Joint Meeting of 'Gesellschaft fuer Pflanzenzuechtung e.V.' and 'Deutsches Maiskomitee e.V.' (Stuttgart, Germany, June 2008), Agronomy Day of the College of ACES/UIUC (Urbana, IL, August 2008), 2008 Annual ASA-CSSA-SSSA Meeting (Houston, TX, October 2008), International Conference on Conventional and Molecular Breeding of Field and Vegetable Crops (Novi Sad, Serbia, November 2008), Germplasm Enhancement in Maize Annual Meetings (Chicago, IL, December, 2008), and at multiple departmental seminar series (University of Wisconsin, University of Illinois, National Taiwan University)
- The maize breeding program has currently five PhD students and four MS students.

Minnesota Station Report
Submitted by Rex Bernardo Department of Agronomy and Plant Genetics University of Minnesota, St. Paul, MN

Mission and Program Description
My mission at the University of Minnesota is (i) to discover new ways of breeding corn, (ii) to breed corn for new uses, and (iii) to educate future plant breeders. My current research focuses on exploiting cheap and abundant molecular markers in corn breeding, breeding for dwarf corn, and the prospects of breeding corn for both grain yield and stover quality for cellulosic ethanol. My work involves theoretical research, computer simulation, molecular marker analysis, and field experimentation.

2008 Program Highlights
- Published a major invited review entitled Molecular markers and selection for complex traits: Learning from the last 20 years in Crop Science. Plant breeders have learned how to routinely map quantitative trait loci (QTL) but the great majority of QTL remain unexploited in breeding programs. I speculated that future applications for complex traits will likely focus on predictive methodologies for marker-based selection prior to phenotyping and for marker-based selection without QTL mapping. These applications will take advantage of cheaper costs of genotyping than of phenotyping.
- Conducted research on the choice of generation for inducing doubled haploids in maize. Previous studies have suggested that the low frequency of recombinants in doubled haploids may reduce the response to selection. From simulation studies, I found that selection responses were up to 4-6% higher when doubled haploids were induced from F2 plants instead of the usual F1 plants. If year-round nurseries are used and new F1 crosses for inbred development are initially created on a speculative basis, the development of doubled haploids from F2 rather than F1 plants should not cause a delay in inbred development.
- Patricio Mayor (Ph.D. student, funded by his company Syngenta Seeds) and I continued our studies on the joint use of doubled haploids and molecular markers in maize breeding. We found that doubled haploid populations are most useful in genomewide selection and marker-assisted recurrent selection for traits controlled by many QTL and with low heritability but have limited value over F2 populations in detecting major QTL for introgression. Patricio and I have also submitted a manuscript that describes an empirical evaluation of the doubled haploid + marker-assisted breeding schemes that we have investigated.
- Completed the phenotypic analysis (M.S. thesis of Magan Lewis) and the marker analysis (part of Ph.D. thesis of Robenzon Lorenzana) for our USDA-funded research on Strategies for using molecular markers to simultaneously improve corn grain yield and stover quality for ethanol production. Magan found high heritabilities and favorable genetic correlations among traits and concluded that there is no genetic impediment to breeding corn for both grain yield and stover quality for ethanol. Benzon did not find any major QTL for any of the stover quality traits and found that predictions of genotypic value were more accurate if the predictions were based on all available markers rather than only the markers with significant effects. The research has now transitioned to marker-based selection for grain yield, agronomic traits, and stover-quality traits. This research on marker-based selection will be part of Jon Massman's Ph.D. thesis.
- Recruited two new students in addition to Jon Massman. Cathrine Ziyomo (Zimbabwe) is a Ph.D. student supported by an AgGrad (Methodist Church) fellowship. Cathrine will work on the breeding and genetics of both N-use efficiency and drought tolerance in maize. Christopher Schaeffer (Minnesota) is an M.S. student supported by a Pioneer Hi-Bred Plant Breeding Fellowship. Chris will be working on response to selection for hybrid grain yield and agronomic traits in dwarf corn, as well as forage quality of dwarf corn.
- Bruno Poupard, a visiting scientist in my program, finished his research on machine-learning methods in marker-assisted selection. Bruno found that machine-learning methods are not any better than statistics-based methods that are already in place for marker-based selection.

Submitted by Sherry Flint-Garcia USDA-ARS Columbia, MO

Mission and Program Descriptions
Maize research at the in Columbia Missouri (USDA ARS and University of Missouri) is primarily genetic in nature. Although there is currently no active corn breeding program, several programs have applied projects that require large-scale field trials. These include Mike McMullen (USDA ARS), Sherry Flint-Garcia (USDA ARS), Bruce Hibbard (USDA ARS), and Georgia Davis (University of Missouri, Plant Sciences).

Other active maize researchers in Columbia and/or the ARS Plant Sciences Research Unit include: Jim Birchler (Biological Sciences), Ed Coe (professor emeritus), Toni Kazic (Bioinformatics), Gerry Neuffer (professor emeritus), Kathy Newton (Biological Sciences), and Mel Oliver (Research Leader for the ARS Plant Genetics Research Unit). Ivan Baxter joined ARS located at the Danforth Center in St. Louis, with plans to work on maize genetics beginning in summer 2009.

2008 Program Highlights
Mike McMullen:
To access the extensive genetic variation present in maize inbred lines, Mike and ARS scientists at Ithaca NY and Raleigh NC have developed a new genetic resource to enable joint linkage-association analysis called nested association mapping (NAM). To form the NAM population, 25 extremely diverse inbred maize lines were crossed to the B73 reference line, and 5000 recombinant inbred lines were created. The NAM genetic map consists of 1106 loci, and has a total genetic length of 1400 cM making it the most powerful genetic resource for the dissection of complex agronomic traits for any species. The NAM population has been phenotyped in multiple environments for up to 30 traits. As an example of the power of NAM, the analysis of flowering time has resulted in identification of ~ 50 loci controlling the variation in flowering time across maize inbred lines. The NAM population has been deposited in the Maize Genetic Stock Center and has been adopted by the maize community as the central genetic resource for trait characterization.
Sherry Flint-Garcia:
Sherry has developed ten introgression libraries of teosinte, each derived by backcrossing a different teosinte accession into B73, an elite maize inbred line. Eight of these libraries comprising 640 maize lines have been characterized with molecular markers to define which chromosomal regions are from the teosinte parent. Each line contains an average of 3 different chromosomal segments encompassing ~4% of the teosinte genome. A subset of five populations was evaluated for disease resistance and other agronomic traits. The development and evaluation of these maize-teosinte insertion libraries will enable geneticists to test hypotheses regarding the impact of domestication on corn improvement, and breeders to reintroduce valuable genetic variation into maize germplasm for very specific genomic regions.
Bruce Hibbard:
Transgenic corn that controls the corn rootworm is a viable alternative to insecticides for managing the most economically important pests of corn. The agricultural industry has adopted a high dose/refuge strategy as a means of delaying the onset of insect resistance to transgenic crops, but the Bt corn products developed for corn rootworm control have been introduced with less than high-dose. Bruce has developed colonies of the western corn rootworm that survived the Bt product in the greenhouse along with an unselected colony. After three generations of full larval rearing on Bt corn, rootworm larvae survived equally on Bt and susceptible corn in greenhouse trials. In dose-response assays with the protein from the Bt corn on artificial diet, the dose of toxin required to kill half the population was 22-fold greater for the selected colony than the unselected colony. After six generations of greenhouse selection, larval recovery on Bt corn as a ratio of larval recovery on susceptible corn in the field was 11.7-fold greater for the selected colony than the unselected colony. The results suggest that rapid response to selection is possible in the absence of mating with unselected beetles, emphasizing the importance of effective refuges for resistance management.

Impact
Maize research at Missouri may be described as ranging from basic biology to applied quantitative trait analysis. Members of the four large-scale projects focus on trait dissection for corn rootworm, drought, insect, and disease resistance, all traits that impact maize production. All four projects also utilize diverse germplasm (inbred lines, landraces, and teosinte) to identify germplasm with novel alleles for trait improvement. Although Missouri does not have a corn breeding program per se, we are making great strides in understanding the genetic basis of traits of economic value while evaluating diverse germplasm that is critical for diversifying the genetic base of corn.

New York State Report
Submitted by Margaret Smith Cornell University Ithaca, NY

In 2008, we started off with generally dry weather in May that helped with getting the corn crop in the ground in a timely manner. Temperatures were a bit cool but overall conditions for planting were good. Temperatures were above long-term averages around the state in June and July, with some record-breaking heat in the central region of the state in early June. Rainfall was above average for June and quite a bit above average for July. The Champlain Valley in June and Central Lakes area in July were especially wet. A storm with very high winds passed through northern New York in mid July, knocking down large trees in the Chazy area. Seasonal or slightly cool temperatures prevailed in August, with rainfall about average in much of the state. Conditions were a bit dry in the St. Lawrence Valley and a bit wet in the western part of the state. September was generally a bit warmer than long-term averages and tended to be dry. The southeast corner of the state was wet, probably due to effects of tropical storm Hanna early in the month, which also caused lodging in the Hudson Valley. Winds from the edges of Hurricane Ike caused stalk lodging pressure around central and northern parts of the state, particularly at Sackets Harbor. As we moved into October, temperatures were a bit cool and conditions were wetter than long-term averages, slowing grain dry-down and harvest operations. The last week of October brought considerable rain and snow. A foot of snow on the hurricane-lodged corn near Sackets Harbor caused some losses. With cool conditions continuing into November, much corn around the state stayed standing in the field later than usual and harvest continued slowly. By early fall, rust and eyespot were common in central and northern parts of the state, and anthracnose leaf blight and gray leaf spot were present in central and southern parts of the state. Northern leaf blight and European corn borer were noticeable at isolated locations.

Overall, there were 1.13 million acres of corn planted in the state. Of this total, 445,000 acres were harvested as silage and the state average silage yield was 20 tons/acre, which topped the previous record of 18 tons/acre in 2006. Another 640,000 acres were harvested as grain. Despite the challenging harvest conditions, the state average corn grain yield was reported as 144 bu/acre; 15 bu/A above the previous state record grain yield from 2006!

North Dakota Report
Submitted by Marcelo Carena North Dakota State University
BRIEF SUMMARY OF RESULTS
During 2007-2008, nine corn products were developed and released as new sources of early maturing and genetically diverse germplasm. These new cultivars were requested by 21 public and private institutions so far. The project has achieved the goals proposed because of activities that have integrated pre-breeding with cultivar development. The project has focused on corn germplasm adaptation and improvement, inbred line development, extensive hybrid testing of NDSU lines and industry lines, and continuous training of applied corn breeders. Corn breeding and testing efforts have significantly increased. The program has conducted 65 replicated experiments in 2008 including 22,360 plots across 22 locations, an expansion from <5,000 plots across five locations before 1999. Compared to top industry checks top NDSU hybrids had over 200% better drought and cold tolerance (through traditional breeding approaches and unique testing locations, e.g. high Montana elevations, western ND), over 150% improvement in grain moisture at harvest and fast dry down (especially in 2008), and over 110% on test weight, lodging resistance, extractable and fermentable starch, grain oil, grain protein, and over 105% for grain yield under dry land and, especially, under irrigated conditions. Most of these lines have been advanced for more multi-location, multi-trait, and multi-stage evaluation in 2009.

We have initiated and continued extensive partnerships with seed companies on testers, technology access (e.g. GMO, double-haploids, SNP marker technology, robotics), breeding approaches to drought tolerance, value added traits (e.g. starch utilization), test weight, and fast dry down with traditional and modern technologies. As a consequence of our trip to southern MN (Olivia, MN) breeding access to germplasm resulted to be very successful. Four graduate students, one research specialist, and several trainees were mentored in our breeding program during this period. National and international visitors were hosted and walked our nurseries, including representatives from major U.S. companies. The breeding program, through its activities, has also directly served several graduate advanced teaching courses (e.g. genetics and plant improvement, quantitative genetics, crop breeding techniques, and advanced plant breeding).

Without exceptions, early maturing hybrids including NDSU experimental lines showed better performance than industry hybrids in 2008 which shows the importance of the need to have reliable and stable early maturing hybrids developed exclusively for ND environmental conditions exclusively. ND challenging conditions were especially present in 2008. Data of all experiments are available upon request. Scientific peer-review publications, plenary lectures, and scientific oral presentations are also available upon request.

Five manuscripts were published or accepted for publication from former graduate students (two from Eno, one from Sezegen, one from Osorno, one from Jumbo). M. Melani is the only former graduate student from the NDSU corn breeding program that has not published his research and it is, therefore, the exception. Student work by Eno and Yang has actively assisted in the release publication of four early maturing inbred lines and four early maturing populations.

Ohio Agricultural Research and Development Center
Submitted by Rich Pratt Dept. of Horticulture and Crop Science The Ohio State University, Wooster, OH

Mission and Program Description
The OSU maize breeding and genetics program focuses on improvement of maize germplasm for resistance to infection by pathogenic agents causing foliar disease. Research is also conducted to examine compositional traits as they relate to grain quality characteristics suitable for food, feed, and industrial end-uses. Collaborative research is undertaken in projects involving molecular genetics and breeding for organic production systems. I advise graduate students, serve on graduate student advisory committees, teach two graduate level courses, and serve as Chair of the Graduate Studies Committee.

Program Highlights, March 2008 to February 2009
IPM-CRSP Project:
- Verification of Quantitative Trait Loci (QTLs) Conferring Resistance to Multiple Foliar Pathogens of Maize and their Utility for Marker-Assisted Selection:
The original project was concluded and the former graduate advisee (Dr. Asea Godfrey) has become the Director of the Cereals Program (maize and rice) for the National Agricultural Research Organization in Uganda. The first publication from his dissertation research will be published in Phytopathology (please see below). Breeding lines with high levels of resistance were intercrossed to begin pyramiding resistance genes and crosses of these lines were made to QPM stocks and to Corn Belt testers. Further research and breeding will be conducted be continued as part of a new IPM CRSP project.

Maize Breeding
- Grain samples from diverse populations were evaluated for compositional traits. A large range of phenotypic values were observed. A new Foss InfraXact is being used and the Tecator 1225 has been updated with new calibrations from ISU. Observed compositional values for breeding lines evaluated in 2008 (at 0% mois. basis) were as follows: protein 13.3 to 16.6%, oil 3.4 to 5.1%, and starch 64.0 to 67.7% (B73 values were 12.6%, 4.4, and 67.7%, respectively). Performance evaluations were conducted at two locations in Ohio and in the 700-800 maturity test in Texas, Georgia, and Ohio. Testcrosses between OSU breeding lines were made with Iowa Stiff-Stalk Synthetic (BSSS) and Corn Borer Synthetic testers. Selfing and test-cross production continued in other populations. Other specialty breeding programs are continuing. One testing site is now in transition to organic certification. High wind conditions following Hurricane Ike were experienced in 2008 field tests in Wooster and at South Charleston.

Host Resistance Research
- Corn Redness Syndrome: Research on maize redness (causal agent is the stolbur phytoplasma) continued in cooperation with scientists at the Institute for Plant Protection and the Environment in Zemun, Serbia. The epidemiology of the disease has now been described and will be published in Phytopathology (please see below). Diagnostic procedures necessary to detect the pathogen are being established and research to examine the genetically variable genomic regions of maize bushy stunt and the Stolbur phytoplasmas is underway. Sequencing of the complete genomes of maize bushy stunt phytoplasma and stolbor phytoplasma have has been initiated.

Significant Accomplishments and Impacts:
IPM-CRSP Project
- Research has contributed to our understanding of host responses to infection, assisted the development of effective selection protocols, and increased our understanding of the number and action of genes for resistance. More efficient and expedient development of maize that can resist yield loss will result.

Host Resistance
- Research has established the causal agents, insect vector, and epidemiology of maize redness in Serbia. Management and breeding approaches to address disease losses can now be formulated.

Wisconsin Annual Report
Submitted by Natalia de Leon University of Wisconsin, Madison, WI

The overall goal of our research program is to develop germplasm and scientific information that support the use of corn for silage and as a feedstock for the biofuel industry.

Current Research Projects:
1. Corn silage breeding program: The University of Wisconsin operates a corn silage breeding program focused on the development of corn varieties with enhanced compositional attributes and forage yield. One important source of germplasm of this breeding program is the Wisconsin Quality Synthetic (WQS), specifically designed to produce high-quality inbreds for use as parents for silage hybrids. WQS is continuously improved using a S2-testcross recurrent selection breeding method, and inbreds derived from succeeding cycles of improvement are developed to the S6 stage and released (See http://cornbreeding.wisc.edu/). The nutritional improved characteristic of WQS germplasm are low neutral detergent fiber (NDF), high in vitro true digestibility (IVTD), high NDF digestibility (NDFD), and low lignin concentration. Crosses derived from WQS C3 were evaluated in our 2008 summer trials, and additional S6 lines will be available for release Fall 2009. During summer 2007 the 20 best S2 families from WQS C3 were recombined to create WQS C4. A set of 200 S1s from WQS C4 were developed during the winter nursery of 2007-08 from this later cycle and visually evaluated during the 2008 summer nursery for per se agronomic performance. A selected subset of those lines was selfed during summer 2008 and testcrossed during winter nursery 2008-09 for evaluation during summer 2009.

2. Evaluation of S2-topcross selection for silage quality in the Wisconsin Quality Synthetic (WQS) corn population: WQS was evaluated after the second cycle of selection by Frey et al. (2004). While selection was successful for several silage quality traits, many of the changes were not statistically significant, and it was not clear if increases in silage quality could be attributed to increased digestibility of the stover or an increased contribution from the highly digestible ear. The primary objective of M.S. student Tim Gustafson research project was to evaluate the forage yield and quality attributes of the WQS population after the fourth cycle of selection on both a whole plant and stover level to further investigate the trends previously seen.
In summer 2007, cycles 0 through 3 of the WQS (WQS C0 and WQS C3, respectively) population per se as well as respective testcrosses to two stiff-stalk testers, LH244 and LH332. The entire experiment was done in triplicate: one trial (WQS WP) for whole plant silage analysis, a second trial (WQS ST) with ears stripped at silage stage for stover analysis, and a third trial (WQS BIOFEED) ear-stripped and harvested at physiological maturity. WQS BIOFEED was investigated for changes in stover composition at full maturity during the selection process for silage stage traits. Forage and grain yields, quality composition and other agronomic traits were evaluated. Results from that evaluation indicate that significant linear improvement was seen in whole-plant yield, stover yield, and whole-plant quality both in the population per se and in testcrosses. Starch content has increased in whole-plant samples while ear percent has remained relatively constant suggesting an increase in the grain-to-cob ratio. Overall milk yield on a Mg of dry matter and on a hectare bases have increased with selection. Changes in silage dry matter yield have been greater on a percent basis than changes in silage quality suggesting that the current selection protocol of selecting S2 topcrosses first for yield then for quality may be more efficient at improving yield. A separate selection directly focused on stover quality may be necessary if more rapid improvement in stover composition is desired.

3. Quantitative trait loci controlling yield and feedstock quality: Corn stover has been identified as an important feedstock for production of cellulosic ethanol in North America. In this study, Ph.D. student, Aaron Lorenz evaluated 206 recombinant inbred lines (RILs) of the intermated B73/Mo17 (IBM) population on a per se basis. A subset of the above RILs was testcrossed to a common inbred tester and 127 of those hybrids were also evaluated. Traits assessed included stover yield, theoretical ethanol potential and other relevant stover constituents. Results from this research indicate that no undesirable correlations were observed between agronomic and cell wall traits. QTL were identified for all traits evaluated, but few QTL were in common between inbred per se and testcross evaluations, despite moderate to high genotypic correlations between progeny types. This study provides information that will support the development of dual-purpose corn hybrids that are high in grain yield and also high in yield of digestible cellulosic feedstock.

4. Diallel experiment evaluating dry tonnage contribution and quality of corn stover for biofuel: An experiment was conducted to evaluate the compositional attributes of leaf blade, leaf sheath, stalk, cob, midrib and husk fractions of 23 hybrids. Plants were harvested and dissected into the aforementioned parts at four developmental stages corresponding to V3, V12, R3 and R6. Tissues were dried and ground for compositional analysis, which included neutral (NDF) and acid detergent fiber (ADF) and in vitro ruminal digestibility. Preliminary results for NDF and ADF indicate significant differences among hybrids for most plant parts. Stalk was the largest fraction of whole plant dry matter at R6 and stalk ADF was associated with whole plant ADF at R6. For stalk ADF, no association was found between early developmental stages (V3 and V12) and R6, suggesting that phenotyping for quality at early stages of development is not indicative of quality at R6. Plant part-by-entry and plant part-by-location interactions were significant in R6 and indicate that the relative quality of hybrids could significantly depend on the plant part evaluated and the relative quality of plant parts could significantly depend on the growing environment.

5. Evaluation of endogenous modifiers of expression of grassy tillers1 mutant: The ability to increase plant biomass per acre of land is an ever-growing concern as the biofuel industry continues to expand. Our hypothesis is that lateral branch (tiller) formation is one important method to increase biomass production in corn. Grassy tillers1 (gt1) effects lateral branch development in corn. The goal of this study is to characterize the phenotype and expression pattern of gt1 in backgrounds with varying penetrance, to better understand how it can be used in breeding programs to increase biomass production per unit of area.
Two field trials were conducted to answer some more specific questions.
I. Effect of density on biomass yield of tillering and non-tillering morphologies
II. Effect of row-crop versus equivalent spacing on biomass production potential

6. Great Lakes Bioenergy Research Center (GLBRC): Two primary areas of research are being sponsored by the GLBRC for our group in collaboration with Shawn Kaeppler and Heidi Kaeppler.
I) Development of rapid-cycling, small statured corn varieties. The goal of this project is to develop rapid flowering, small-statured varieties of corn amenable to high-throughput genetic analysis in controlled environments and at locations without access to agronomic production fields.
II) Exploitation of the endogenous genetic variation of corn to identify genes related to important traits for the improvement in the utilization of biomass as a source of feedstock for the biofuel industry. The aim of this project is to identify the genetic locations of genes that explain the differences among diverse corn genotypes.