Germplasm Enhancement of Maize
- 2003 Annual Report
Raleigh, NC Location (from Dr. Major Goodman):
TOTAL GEM YIELD TRIAL PLOTS COORDINATED BY NC STATE: 28,953
GEM Nursery Rows at NC State:
Approximately 1,000 plots were planted for fusarium at Pioneer's Camden, NC location (about 500 of these were for Ames)
Southern rust was scored for 3,850 GEM plots scattered across 6 NC locations.
Gray leaf spot was scored for 1150 GEM plots across 3 NC locations.
About 1,000 new GEM topcross families were produced this year. We also have a carry-over of about 250 from last year.
Public Cooperators with Specific Cooperator Agreements (SCA) in 2003:
At the March 2003 TSG Meeting priority targets for research were discussed and it was generally agreed to direct efforts in several important research areas. This included mycotoxin resistance (aflatoxin and fumonisin), stress resistance, insect resistance (particularly root worm), disease resistance (emphasis on stalk rot), and value-added traits including grain and silage quality. The SCA’s selected in 2003 were based on research projects that address priority targets, and the expertise of the researcher.
Twelve university projects and one USDA-ARS project were supported by GEM in 2003 for a total of $130,000. A summary of each report is provided below, and full reports can be found on the GEM web site in early 2004.
Table 1. Public Cooperators Supported In 2003
Javier Betran, Texas
A&M University: Aflatoxin evaluation of GEM advanced lines with different
fatty acid content.
Martin Bohn, University
of Illinois: Evaluation of advanced GEM lines for multiple insect resistance
and fumonisin concentration.
Mark Campbell, Truman
State University: Combining GEM lines for the development of Amylomaize
VII(>70% amylose) germplasm with increased starch content and improved yield
Marcelo Carena, North Dakota State University: EarlyGEM: Incorporating GEM elite lines in early maize. EarlyGEM is defined as the long term and continuous effort to incorporate GEM elite germplasm into the northern Corn Belt. The goals of the NDSU maize breeding program includes (1) identifying elite exotic genetic materials for adaptation, (2) maximize genetic improvement for maize germplasm adapted to North Dakota, (3) develop improved maize inbred lines, (4) coordinate testing trials, (5)assess potential of maize diversification, and (6) educate plant breeders. The program to evaluate GEM elite lines began in 2001when 152 GEM lines from sets A, B, and C (S3 bulk families) were evaluated for adaptability in North Dakota. The most adapted genotypes were further selected for earliness, disease resistance, and other desirable phenotypes, and selections made within families. The most adapted genotypes were crossed to ND2000, and ND99-16. ND99-16 crosses were discarded since they were 5+days later than ND2000 F1 crosses. Four stiff stalk donors from GEM included GEM3 (CUBA117:S1520-388-1-B), GEM12 (CUBA117:S15-372-1), GEM13 (CHIS775:S1911b-B-B), and GEM21 (AR16026:S17-66-1-B). Selected plants (62 rows) from these lines were crossed to ND2000, and are now at BC1 generation, i.e., GEM3 x ND2000)x ND2000, etc., for each. Selections were made in each F1 for earliness and adaptability, and selected plants used for backcrossing. B73 was used as a check in backcrosses to early elite lines since B73 is late for North Dakota. In addition, testcross performance comparisons will also be made relative to the selected GEM lines. Future plans include planting the BC1 families and selfing the earliest plants. At least 100 BC1:S1 lines will be used for crossing with a tester line for trial evaluation in 6 ND environments.
Jim Coors, University of Wisconsin: Development of inbreds, hybrids, and enhanced GEM breeding populations with superior silage yield and nutritional value. The GEM project has potential for bringing new germplasm into the Corn Belt with excellent grain and silage yield, as well as improved nutritive value. As in the past, in 2003 we continued to evaluate silage yield and nutritive value of the most productive GEM topcrosses identified in grain yield evaluations conducted over the past several years by the GEM project. We now routinely evaluate silage potential of elite GEM topcrosses with high grain yield and suitable maturity (< 120RM). These hybrids are chosen annually based on excellent grain yield in GEM evaluations conducted in previous years throughout the U.S. Corn Belt. If any of these topcrosses have high dry matter yield and good nutritional quality in our UW trials, the respective GEM parent or breeding population is included in the UW inbred development nursery for further inbreeding and selection. In 2003, silage trials continued in GEM A (36 early generation GEM lines topcrossed to HC33, LH185, LH198, LH247, and LH283). The GEM B trials consist of UW developed GEM lines chosen on the basis of topcross silage evaluations in previous years. Two top cross hybrids from GEM A were identified with predicted milk yields greater than 34,000 lbs/acre milk/acre. The two topcrosses with high forage yield were BR52051:N04-76-1 x LH198, and DK212T:N11a12-122-1 x HC33. The former hybrid also had excellent quality (low NDF, high IVD, high NDFD, and high milk/ton). In GEM B trial, one top cross, AR17026:N1019-65008-2-3-2-1 x HC33 was identified with high forage yield and low NDF (suggesting high potential for intake). Formal release of this inbred is being considered for the future. In 2003, a new breeding effort was launched with the Cuba materials-CUBA164:S1517, CUBA164:S15, and CUBA117:S1520. Superior families from each of these breeding crosses will be recombined to form a new breeding population, GEM Quality Synthetic (GQS). Since GQS is 75% stiff stalk background, it can be crossed to the Wisconsin Quality Synthetic (WQS) with the potential to develop high forage yield and superior nutritional quality hybrids.
Jim Hawk, University of Delaware: Inbred line development and hybrid evaluation in GEM breeding crosses. The objectives for the GEM research at the University of Delaware includes (1) the evaluation of 170 breeding crosses for adaptability, maturity, flowering synchrony, standability, plant and ear height, pest resistance, stay green, grain quality and drydown, (2) initiate inbreeding with 15 new breeding crosses (10 SS and 5 NS), (3) make selections among 564 S1 families and make S2’s among selected families, and (4) conduct yield trials of S2 GEM topcrosses in Delaware and Iowa locations. Twenty-six breeding crosses were selected and are recommended for future line development (objective 1). From 320 self pollinations made in each of the 15 new breeding crosses, 498 stiff stalk, and 188 non-stiff stalk S1 ears were selected based on plant and ear phenotype (objective 2). Two hundred forty-six S2 ears were selected from 164 of the 366 stiff stalk S1 families, and 131 S2 ears were selected from 88 of the 198 non-stiff stalk families evaluated (objective 3). Due to hurricane Isabel on the East Coast, it was not possible to have more than a single location of data from the Delaware location (2 of 3 locations lost in Delaware). Most of the yield trial data presented in tables 4-11 are from one location in Delaware, and one location in Iowa (objective 4). Although the data is from a limited number of locations, GEM entries were identified that were above the means of five commercial hybrids in five of the eight experiments. GEM breeding crosses with progeny above the check means included: DK212T:N11a10, DK888:N11a08b, UR13085:N0204, CUBA164:S1511b, and DKB844:S16. The top 25-35% of S3 lines will be advanced, and S2 and S3 lines from selected populations are being test crossed in 2003-2004 winter nursery for 2004 yield trials.
Manjit Kang, Louisiana State University: Identifying resistance to infection by Aspergillus flavus and Fusarium in GEM breeding crosses and advanced breeding lines. The GEM crosses (30) and advanced breeding lines (41) supplied by Dr. Michael Blanco, GEM Coordinator, were planted on 23 April 2003 at Ben Hur Plant Science Farm near Baton Rouge. The experimental design was a randomized complete block with two replications. Each two-row plot was 20 ft long with 40-inch row spacing. Ears of six randomly chosen plants were inoculated as follows: Thirty days after mid-silk, the first row of each plot was inoculated with conidial suspension of Aspergillus flavus and the second row was inoculated with Fusarium verticillioides. In late August, A. flavus- and F. verticillioides-inoculated ears were harvested separately. Ears were shelled and seed has been stored in a freezer. Inoculated kernel samples will be analyzed for percent kernel infection. We expect analyses to be completed by the end of March 2004. Five samples with highest and five samples with lowest kernel infections will be assayed for aflatoxin and fuminosin concentrations.
Richard Pratt, Ohio State University: Optimization of protein and oil value-added traits and their combination with elite Ames and southern GEM lines. This is a new project. High protein and high oil GEM lines, and their sister lines or other closely related lines with desirable agronomic performance, were identified by examination of existing data sets. In total, 1 Set C; 7 Set E; 1 Set F; 6 Set G and 28 lines from the southern GEM (NC State) were selected. Three lines displayed both high grain quality and high agronomic performance in previous tests. The objective will be to verify the reported phenotypes of the selected lines and then to initiate selection within lines, and within newly generated populations for 1) a favorable balance of agronomic and grain quality traits and 2) extreme trait expression per se. DK888N11 materials displayed the following range of responses to natural infection by foliar pathogens: GLS 0% to 5% PLAA; Stewarts Wilt 2% to 15% PLAA; Rust 0% to 15% PLAA; most rows did not show NCLB lesions. The highest yielding individual entry was B73 x DK888N11 F2S2 01RH700055 at 8.26Mg/ha with 34.3% moisture and 43% lodging. Stalk lodging was extremely high in the plot. The mean value for the checks was 57% and for the experimental entries it was 78% with a range from 14% to 96%.
Ken Russell, University of Nebraska: Selection for phosphorous concentration in maize grain. No report submitted. Report available in early 2004.
Margaret Smith, Cornell University: Anthracnose stalk rot resistance from exotic maize germplasm. Anthracnose stalk rot (ASR), caused by Colletotrichum graminicola (Ces.) G.W. Wils., causes stalk rot problems and contributes to increased lodging in New York and throughout many U.S. maize-producing areas. The only economically feasible control of ASR is through resistant varieties and cultural practices that reduce disease incidence. This project aims to develop new maize inbreds with excellent resistance to ASR and good agronomic quality, yield potential, and temperate adaptation (derived from the proprietary temperate inbreds crossed to the exotic populations). Beginning in 1995, screening GEM germplasm resulted in the identification of four breeding crosses having 75% temperate:25% exotic with potential for ASR resistance. Using simultaneous selection for ASR and yield, (beginning with S2 topcross for yield in 1999), the objectives of 2003 include (1) evaluation of S5 and S6 lines and their test cross progeny for ASR, and (2) evaluate the test cross progeny (crossed to both public and Holden’s testers) for yield and agronomic potential. Two GEM derived inbreds (FS8B(T):N1802 15-255 and GOQUEEN:N1603 15-276) appear as resistant or more resistant than the resistant check, DE811ASR. Data from the 2003 experiment for ASR and yield trials is still being collected and not available for inclusion in this report.
Dennis West, University of Tennessee: Breeding lines with exotic germplasm. In 2003, 859 experimental GEM hybrids were evaluated in 18 yield trials in Tennessee. These hybrids were crosses between GEM lines and adapted germplasm. Several experimental hybrids were competitive with commercial check hybrids included in these trials. An experimental hybrid in trial W31 (DKXL380N11F2S2 x T8) yielded 40 bu/a more than the average of 6 check hybrids. The best lines from these GEM accessions will be selected for further testing and incorporation into breeding for new value-added parental lines. Inbreeding and selection was continued in populations resulting from crosses between GEM lines identified in previous trials.
David Willmot and Bruce Hibbard, USDA-ARS, Columbia, MO: Molecular breeding for corn rootworm resistance in maize. Corn rootworm (CRW) (Diabrotica spp.) damage and chemical control costs exceed $1 billion annually. Native plant resistance is needed to complement transgenic approaches to combating this highly mutable pest. Moreover, marginal progress in past decades points to the need for exotic sources of resistance and molecular tools to dissect and deploy their mechanisms of resistance. The objectives of this research are to recombine favorable alleles for CRW resistance and agronomics into elite populations useful for (i) derivation of CRW resistant lines and, (ii) quantitative trait loci (QTL) mapping studies. Results from previous studies in multi-year trials were used to select pedigrees having high levels of CRW resistance for this study. High yielding lines from those pedigrees were used to create synthetic populations. Half sib families were screened for CRW in 2003 by artificial infestation at two locations. CRW screening was completed before flowering on a 0-3 scale and families with damage below 0.4 nodes of roots were random mated. Pedigrees with good CRW resistance and agronomics were derived from breeding crosses CHIS:N1912, UR13085:N0215, DK212T:S11, and DK888:S11. In 2003, we completed an initial molecular marker study by selective genotyping of the most susceptible and resistant lines from two non-GEM populations that we developed. Allelic frequencies of marker alleles contrasted significantly for 10 or 11 loci for each population. Two of three insect resistance loci mapped by others co-segregated accordingly with our materials.
Wenwei Xu, Texas A&M University: Characterization and use of GEM breeding crosses for drought tolerance, grain mold resistance, and corn earworm resistance. The objective of this research is to (1) conduct a second year field evaluation of 71 GEM breeding crosses for drought tolerance, grain mold resistance, and CEW resistance; (2) to conduct second-year yield trials of the topcrosses of the inbred lines derived from GEM germplasm; (3) to continue inbred line development from selected GEM breeding crosses; and (4) to make topcrosses of the GEM inbred lines and advanced lines for 2004 trials. In 2003, the CEW pressure was moderate and lower than in 2002. Over two years, DK888:N11a, DKXL380:N11a, BR51501:N11a, ANTIGO1:N16, CUBA84:D27, CML329:N18, SCROGP3:N411a, DK212T:N11a, BG07040:D27, and ANTIGO03:N12 had the lowest CEW penetration, while CH04030:N0306, GOQUEEN:N16, AR01150:N0406, AR17026:N1013, and SCRO1:N110 had the highest CEW damage. The average percentage of molded kernels (mold) was 4.8% ranging from 2.7% to 8.8%. The molds in GOQUEEN:N16 were significantly higher than the average. Molds were highly correlated with CEW penetration (r = 0.70**). None of the 74 entries had molds significantly below the test mean.
The average yield was 110 bu/a ranging from 45.8 (CHIS462:N08a) to 168.5 bu/a (P3223). Three check hybrids P3223, P34K77, and B73xMo17 were ranked as 1, 3, and 60 respectively. Top 10 yielding GEM breeding crosses were ANTIG03:N12, UR11002:N0308b, ANTIGO03:N1216, AR16026:N12, PRICGP:N1218, ANTIG01:N16, SCRO1:N13, CHIS775:N1920, AR03056:N0902, and CH05015:N1204. Their yields were 132 to 148 bu/a. Three top crosses (AR01150:N0406) F8A2 x B110, (AR01150:N0406) F8A1 x B110, and (FS8A(T):N1801)F7-2 x B110 had an average yield of 187, 181, and 186 bu/a, which was 13-14% higher than the check average. They also had tall plants suitable for silage. The hybrids made with (AR01150:N0406) F8A1, (AR01150:N0406) F8A2, (FS8A(T):N1801)F7-2, and SCROGP3:N1411a also performed well in 2002. These lines are now uniform and have been characterized for their maturity, drought and heat tolerance, insect resistance, and other agronomic traits under different environments in 2002 and 2003. Release proposals will be submitted to the Texas Agricultural Experiment Station by the end of 2003.
Ames: USDA-ARS Plant Introduction Research Unit.
NC State University
Dr. Major Goodman, Professor, GEM Collaborator
The emphasis in summer 2003 was to generate more S1 families for planting in 2004. Sixteen breeding crosses were worked through in kind support in summer, and three were assigned to cooperators for winter 2004-2005. Twelve breeding crosses were selfed to make S1’s in Ames in summer 2003 bringing the total to 31. At the March 2003 TSG Meeting it was agreed that 30 breeding crosses could be managed per year by revising the protocol to make 250-300 selfs per breeding population instead of 1,000. Approximately 50 S2 lines will ultimately be selected from the 250 S1 families planted next summer. To accelerate the re-testing process, winter isolation in-kind support was generously provided in 2003-2004 by Pioneer, Syngenta, and Mycogen.
Table 2. Private In-Kind Nursery Support – Summer 2003
Table 3. Private In-Kind Support - Winter 2003-2004
GEM Yield Trials in 2003
Table 4. Private Cooperator Yield Trials 2003*
* Other GEM cooperators providing in-kind yield trial support in 2003 were Benson Seed Research, FFR Cooperative, Hoegemeyer Hybrids, Illinois Foundation Seed, National Starch, PAU Seeds, Schillinger Seed, and SeedDirect. We also acknowledge support of Iowa Crop Performance Test-Corn.
GEM Project Data and information are available via the GEM web site at:
POPGEM-Submitted by Ken Ziegler:
In 2003, the fourth year of the POPGEM program, 9 private cooperating companies and 3 public cooperators were involved with the program. The original protocol for year 4 was postponed for a year while the economic situation and the future of the popcorn breeding program at ISU were dealt with. Protocol for 2003 was the same as that followed for 2002: private cooperators planted each of the three heterotic populations and made selections for improved plant type and ear type within each population, and public breeders intermated within each heterotic group, the selections made by private companies the previous year.
Additional POPGEM work in the Iowa State University breeding program included a third generation of intermating 3 dent corn populations to the POPGEM populations: Leaming was intermated within Supergold, Midland was intermated within Amber Pearl, and Hallauer Long Ear was intermated within South American. These three dent by POPGEM populations will be the ones sent to private cooperators in 2004 for crossing to their largest expansion inbred lines to initiate the second phase of the POPGEM protocol. Also, based on 2000 data, the best popping 50% and 25% original GEM dent lines after 2 generations of intermating were selfed within the Stiff Stalk group (51 lines) and the Non-Stiff Stalk group (17 lines). The above selfs were made to make selections for improved popping expansion within each subpopulation. Bulks of the best popping lines of these 2 populations will also be sent to private cooperators in 2004 for making crosses to their largest expansion inbred lines. Late maturing lines from each of these two populations were crossed to early material to shorten their maturity. The Stiff Stalk group of lines was crossed to an early Cateto and the Non-Stiff Stalk group of lines was crossed to an early long-eared flint. The development of a dent sterile version of each of the three heterotic POPGEM populations continued with the second year of intermating to the heterotic POPGEM populations. Ten of the best popping inbred lines developed from the original 50% and 25% GEM dent populations and selected in 2002 were selfed for seed increase and popping expansion evaluation. And, 30 hard textured GEM lines selected from the GEM 2003 nursery are being evaluated for popping expansion.
GEM’s objective via conventional intercrossing and selection methods, is to widen the germplasm base of commercial hybrid corn in the United States through the introduction and incorporation of novel and useful germplasm gathered from around the globe.
The GEM breeding protocol was revised to implement revisions agreed upon by the GEM TSG in March 2003. The changes include a reduction in the number of plants selfed per breeding cross (from 1,000 to 300 S1’s made-keep 250 S1 ears) and the number of S2 topcrosses tested per population (from 200 to 50 S2 topcrosses). Selection intensity remains the same as previously, i.e. 20% of 250 S1 progeny should be selected, and 50 S2 ears selected for making topcrosses. It was emphasized that breeding crosses with good S2 top cross progeny performance should be worked again to “re-tap” good sources effectively. It was also agreed that S2 seed from the best 10 (or 10%, whichever is greater), be returned to the Coordinator for increase, making top crosses, and sharing with GEM cooperators. Seed from individual S1 ears should also be sent to the Coordinator as per the previous protocol.
Germplasm recommended for release to GEM cooperators is based on consistent agronomic performance. During the September 2003 TSG meeting it was recommended that two years of trial data be available before recommendation and distribution to GEM cooperators. Cooperators are encouraged to study two year results independently and may request additional germplasm not appearing on the recommended list if supplies are available. Cooperators who request “non-recommended” lines agree to increase and share the seed with other GEM cooperators, and should return enough seed to the Coordinator for distribution. Access to germplasm from first year S2 topcross trials is available to GEM cooperators on a request basis but will be dependent on seed supply. Since S2 seed is from a single ear, supplies are limited. Cooperators receiving S2 seed agree to increase seed and share S3 bulk inventory with GEM, and/or make S3 topcrosses for retesting in the GEM network.
Second year trials of S2, S3, and S4 bulk topcrosses were conducted in ten experiments with 331 GEM entries in 2003. Sixteen hybrids performed favorably in reference to check hybrid means, and/or Y/M over 2 years data. All of the selected hybrids have had good stalk and roots based on the data available. The sixteen GEM lines are available in 50 k quantities and are recommended for release to GEM cooperators for 2004. Some of the lines are likely candidates for public release pending lab quality results, and further study. GEM will increase and maintain the lines on the recommended list. Data was presented at the GEM Cooperator meeting in Chicago for the following lines:
Table 5. Recommended GEM Lines
Lab Analysis: near infrared reflectance spectroscopy (NIRS):
No formal lab report is available due to the absence of the Quality Traits Lab Manager. A lab report will be posted to the GEM web site after analysis is completed following Sue Duvick’s return to work in early 2004. NIR analysis was conducted on many second year GEM lines developed in the Midwest, and NC GEM lines from “PUBWIN.” NIR data for 2003 is not currently available for first year trial GEM lines. Some of the preliminary NIR analysis data available in 2003 supports results found in 2002, and reported in the 2002 Annual Report:
CUBA164:S1511b-325-1-B-B had high protein levels in 2002, and 2003 (16.6% and 13.9% respectively. This was 4.5% and 3.7% greater than the check means (B73, Mo17, B73xMo17) in each year respectively.
SE32(BR52051):S17 F2S4 2011-01 developed in NC had the highest oil content in 2002 (5.1%) and 2003 (4.68%). It also had high protein content in 2002 and 2003 (15.0% and 12.52% respectively). This protein level was 3% and 2% greater than the check means (B73, Mo17, B73xMo17) in each year respectively.
DK212T:S11 F2S4 2089-01 developed in NC had high protein in 2002, and 2003 (17.0% and 12.9% respectively). This was 5% and 3% greater than the check means (B73, Mo17, and B73xMo17) in each year respectively.
Lab Analysis: differential scanning calorimetry (DSC):
Starch thermal properties are predictive of functionality of starch for food and industrial usage. In 2002, DSC analysis was made among some of the GEM set lines (mostly S3 bulk generations), and extreme values were found for starch thermal properties in families from various breeding crosses. Starch thermal properties measured included: (1) peak onset of gelatinization temperature (ToG), target range <62 and =>69 (2) range of gelatinization temperature (RnG), target range <6 and >12 (3) enthalpy of retrogradation (ΔHR), target range <1 cal/g (4) percent retrogradation (%R), target range <20% and >60% (5) peak height index of thermogram (PHI), target range <0.5 and >1.2. Families with interesting starch thermal properties in 2002 came from the following five breeding crosses:
CUBA164:S15- extreme values (low to high) were found for ToG, RnG, and PHI.
AR16026:S17- extreme values (low to high) were found for ToG, RnG, and PHI.
AR16035:S19- low RnG and high ΔHR.
DKB844:S1601- extreme values for RnG, ΔHR, and PHI.
Families from all of the above breeding crosses were planted in Ames 2003 nursery and are being analyzed for second year DSC data (data not yet available). In addition, all of the families were included in 2003 isolations and will be yield trialed for the second year in 2004. The objective is to identify good agronomic performance with favorable starch properties.
Several advanced stage GEM inbreds with DSC data from 2002 included:
DKXL370:N11a20-322-1-B had low PHI.
DK212T:S11 F2S4 2131-01 - high ToG, and high PHI.
DK888:S11 F2S4 2146-01- high ToG, and high PHI.
DK212T:S11 F2S4 2111-01- high ToG, and high PHI.
Data from 2003 DSC is pending for above.
Lab analysis (Amino acids):
An interesting study on amino analysis of GEM germplasm is in progress in collaboration with USDA-ARS scientist, Paul Scott in Ames. The objective is to assess the levels of important amino acids in maize grain, and to develop efficient and less costly analytical methods. If successful, screening maize for amino acid content may be feasibly used on a routine basis in corn breeding programs. Sixty-four GEM samples were analyzed for amino acid content in 2002. Selected lines with above average amino acid content for lysine and tryptophan in 2002, were planted in 2003. In addition, some new inbreds were also included for a total of eighty-six samples planted in 2003. Several GEM lines were identified having levels of lysine, or methionine greater than the check inbreds B45 o2, (the lysine and tryptophan check), and B101 (methionine check). One GEM line was identified having levels of both lysine and methionine above the check means of B45 o2 and B101 respectively. This same inbred had above average tryptophan content (but less than the check, B45 o2). Although preliminary studies are encouraging, the correlation of 2002 and 2003 data was lower than expected. Studies are continuing to determine if inconsistencies are due to trait instability, lab procedures, sample size, or other. The study is presently being repeated with the original 2002 ground seed samples, and 2003 samples in a simultaneous experiment. Results will be reported when further information is available.
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