Assessing GEM accessions for agronomic
performance and resistance to aflatoxin
accumulation in grain in the Midsouth.
Mike Clements
USDA-ARS
Corn Host Plant
Resistance
Research Unit
Located at
Objectives of CHPRRU:
Determine biotic and abiotic
factors that increase
vulnerability of corn to
A. flavus infection and
aflatoxin accumulation
Objectives of CHPRRU:
Determine biotic and abiotic
factors that increase vulnerability
of corn to A. flavus infection and
aflatoxin accumulation
Identify/develop germplasm
with favorable agronomics
and resistance to A. flavus
infection, aflatoxin
accumulation, and
insect feeding.
Objectives of CHPRRU:
Determine biotic and abiotic
factors that increase vulnerability
of corn to A. flavus infection and
aflatoxin accumulation
Identify proteins, molecular
markers, and genes
associated with
Identifyresistance.
germplasm with
resistance to A. flavus
infection, aflatoxin
accumulation, and insect
feeding.
Objectives of CHPRRU:
Determine biotic and abiotic
factors that increase vulnerability
of corn to A. flavus infection and
aflatoxin accumulation
Identify proteins, molecular
markers, and genes
associated with resistance.
Identify/ develop germplasm
with favorable agronomics
and resistance to A. flavus
infection, aflatoxin
accumulation, and
insect feeding.
My role within CHPRRU:
Determine biotic and abiotic
factors that increase vulnerability
of corn to A. flavus infection and
aflatoxin accumulation
Identify proteins, molecular
markers, and genes
associated with resistance.
Identify/ develop germplasm
with favorable agronomics
and resistance to A. flavus
infection, aflatoxin
accumulation, and
insect feeding.
My role within CHPRRU:
Determine biotic and abiotic
factors that increase vulnerability
Release
of corn to A. flavus infection and
aflatoxin accumulation resistant,
agronomically
favorable
Inbred lines
Identify proteins, molecular
markers, and genes
associated with resistance.
Identify/ develop germplasm
with favorable agronomics
and resistance to A. flavus
infection, aflatoxin
accumulation, and
insect feeding.
My role within CHPRRU:
Determine biotic and abiotic
factors that increase vulnerability
Release
of corn to A. flavus infection and
aflatoxin accumulation resistant,
Publish
information
Identify proteins, molecular
markers, and genes
associated with resistance.
agronomically
favorable
Inbred lines
Identify/ develop germplasm
with favorable agronomics
and resistance to A. flavus
infection, aflatoxin
accumulation, and
insect feeding.
My objectives:
• Develop a rapid, inexpensive assay for screening
a large quantity of samples
My objectives:
• Develop a rapid, inexpensive assay for screening
a large quantity of samples
• Identify novel sources of resistance
with an eye toward yield!
My objectives:
• Develop a rapid, inexpensive assay for screening
a large quantity of samples
• Identify novel sources of resistance
with an eye toward yield!
• Develop and release inbred lines with superior
resistance and functional agronomics that are
useful for private and public breeding programs
My objectives:
• Develop a rapid, inexpensive assay for screening
a large quantity of samples
• Identify novel sources of resistance
with an eye toward yield!
• Develop and release inbred lines with superior
resistance and functional agronomics that are
useful for private and public breeding programs
• Collaborate!
Why
GEM?
Collaborative effort: USDA-ARS
Land-grant universities
Industry
Objective: Widen the germplasm base of commercial
hybrid corn by introducing and incorporating
novel, useful germplasm gathered from
around the globe.
Evaluation of GEM Accessions
2003 - 2004
Inoculated, replicated trials at Mississippi State, MS
Characteristics examined:
+ Aflatoxin concentration in grain
+ Severity of Aspergillus ear rot
+ Maturity (MGDU planting to silking)
-- Grain quality and weight
-- Plant characteristics
Evaluation of GEM Accessions
2003 - 2004
• 28 GEM breeding crosses
- Temperate x “Exotic”
Tropical
Sub-tropical
Evaluation of GEM Accessions
2003 - 2004
• 28 GEM breeding crosses
- Temperate x “Exotic”
- 25 to 50% exotic
Tropical
Sub-tropical
Evaluation of GEM Accessions
2003 - 2004
• 28 GEM breeding crosses
Tropical
- Temperate x “Exotic”
Sub-tropical
- 25 to 50% exotic
- Most genes not “fixed”
(~100% heterozygous)
Evaluation of GEM Accessions
2003 - 2004
• 127 GEM lines
- Selected from breeding crosses for
yield, agronomics or value added traits.
Evaluation of GEM Accessions
2003 - 2004
• 127 GEM lines
- Selected from breeding crosses for
yield, agronomics or value added traits.
- % exotic??
Evaluation of GEM Accessions
2003 - 2004
• 127 GEM lines
- Selected from breeding crosses for
yield, agronomics or value added traits.
- % exotic??
- Most genes “fixed”
(~75 to 97% homozygous)
Evaluation of GEM Accessions
2003
• 83 testcrosses of GEM lines
- GEM line x commercial inbred
Suggestive of hybrid performance
Evaluation of GEM Accessions
2003
• 83 testcrosses of GEM lines
- GEM line x commercial inbred
Suggestive of hybrid performance
Unfortunately, multiple testers!
Value of comparisons among testcrosses was minimized
GEM Breeding Crosses
2003 - 2004
Data from 28
Aflatoxin Ear rot
Breeding crosses (ng g-1)
(%)
Average
MGDU50
2003 2004
472
9
1460 1531
Minimum
70
4
1350 1425
Maximum
1544
21
1821 1871
Pedigree
CUBA164:D27
Aflatoxin (ng g-1)
Ear rot
(%)
Grain wt per
ear (g)
2 yr avg
2 yr avg
2003
2004
MGDU50
2003
2004
70
4
119
143
1709
1660
Resistant Mo18WxMp313E
83
5
111
135
1821
1796
BVIR103:S0411a
112
10
.
124
.
1425
DKB830:S11a18
124
6
.
105
.
1460
BR51675:N0620
136
6
118
1392
1425
146
8
.
1871
BR51403:N16
159
4
143
131
1434
1617
ANTIG01:N16
178
6
134
139
1477
1539
CUBA84:D27
227
5
149
128
1466
1660
BG070404:D27
229
6
117
120
1529
1617
DKXL380:N11b20
251
6
.
126
.
1460
GUAT209:S1308b
304
11
.
90
.
1460
Mod Resist MP716xMp717
359
5
147
.
1512
.
Susceptible Mp305xMp714
446
11
132
152
1504
1617
Susceptible Mp339xSC212M
464
10
158
133
1434
1617
5
7
24
117
91
472
9
127
117
1460
1531
Minimum
70
4
97
67
1350
1425
Maximum
1544
21
158
152
1821
1871
Resistant MP715xMp717
LSR / LSDα=0.05
Grand mean
123
.
67
.
GEM Lines
2003 - 2004
Aflatoxin (ng g-1)
Ear Rot (%)
2003
2004
Two yr avg
Average
Minimum
556
9
1309
13
23
4
Maximum
2147
>2400
94
Data from 127
GEM lines
GEM Lines
2003 - 2004
Average
Minimum
Maximum
Grain quality (1-5)
Grain wt ear-1 (g)
2004 only
2004 only
3
1
5
45
20
90
GEM Lines
2003 - 2004
MGDU50
Average
Minimum
Maximum
SWCB (1-9)
2003
2004
2004
1562
1350
2040
1627
1460
2263
8
3
9
Top Resistant GEM Lines
2003-2004
Aflatoxin
Ear Rot
(%)
(ng g-1)
Pedigreeh.
2003
2004
2 yr avg
Resistant
Mp313E
9
13
8
Resistant
Mp715
.
42
11
2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib-B
24
163
5
2283-01_XL380_S11_F2S4_9229-Blk20/00-sib-B
24
217
5
2258-03_XL380_S11_F2S4_71/97_Bulk/98-sib-B
48
239
5
.
357
9
233
382
4
2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib-B
25
392
5
Resistant
Tuxpan
20
442
5
Mod Resistant
NC300
80
530
16
Susceptible
NC258
672
1774
15
6
2
13
556
1309
23
Minimum
9
13
4
Maximum
2147
2400
94
CH1S775:S1911b-16-1-B-B-B
NC298
LSR / LSDα=0.05
Grand mean
Top Resistant GEM Lines
2003-2004
Aflatoxin
Ear Rot
(%)
(ng g-1)
Pedigreeh.
2003
2004
2 yr avg
Resistant
Mp313E
9
13
8
Resistant
Mp715
.
42
11
2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib-B
24
163
5
2283-01_XL380_S11_F2S4_9229-Blk20/00-sib-B
24
217
5
2258-03_XL380_S11_F2S4_71/97_Bulk/98-sib-B
48
239
5
.
357
9
233
382
4
2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib-B
25
392
5
Resistant
Tuxpan
20
442
5
Mod Resistant
NC300
80
530
16
Susceptible
NC258
672
1774
15
6
2
13
556
1309
23
Minimum
9
13
4
Maximum
2147
2400
94
CH1S775:S1911b-16-1-B-B-B
NC298
LSR / LSDα=0.05
Grand mean
Top Resistant GEM Lines
2003-2004
Aflatoxin
Ear Rot
(%)
(ng g-1)
Pedigreeh.
2003
2004
2 yr avg
Resistant
Mp313E
9
13
8
Resistant
Mp715
.
42
11
2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib-B
24
163
5
2283-01_XL380_S11_F2S4_9229-Blk20/00-sib-B
24
217
5
2258-03_XL380_S11_F2S4_71/97_Bulk/98-sib-B
48
239
5
.
357
9
233
382
4
2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib-B
25
392
5
Resistant
Tuxpan
20
442
5
Mod Resistant
NC300
80
530
16
Susceptible
NC258
672
1774
15
6
2
13
556
1309
23
Minimum
9
13
4
Maximum
2147
2400
94
CH1S775:S1911b-16-1-B-B-B
NC298
LSR / LSDα=0.05
Grand mean
Top Resistant GEM Lines
2003-2004
Grain
quality (1-5)
Pedigree
2004
MGDU50
2003
2004
Resistant
Mp313E
1
2040
2263
Resistant
Mp715
1
.
2229
2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib-B
3
1512
1574
2283-01_XL380_S11_F2S4_9229-Blk20/00-sib-B
2
1709
1796
2258-03_XL380_S11_F2S4_71/97_Bulk/98-sib-B
4
1582
1705
CH1S775:S1911b-16-1-B-B-B
4
.
1617
NC298
2
1667
1660
2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib-B
3
1512
1617
Resistant
Tuxpan
4
1802
1871
Mod Resistant
NC300
3
1671
1705
Susceptible
NC258
3
1667
1705
LSR / LSDα=0.05
1
137
92
Grand mean
3
1565
1624
Minimum
1
1350
1460
Maximum
5
2040
2263
Testcross aflatoxin eval 2005
• 16 GEM lines identified as resistant or susceptible in
previous work
• 5 public inbred lines
(Mp494, Mp715, Mp80:04, NC258, NC320, Tx601)
• 10 experimental lines from USDA-ARS at MS State.
• 1 commercial check (Terral Seeds TV2100),
• 1 susceptible check (GA209/SC212M)
• 1 resistant check (Mp313E/Mo18W),
• The cross LH195/LH210.
Top lines: Testcross aflatoxin eval 2005
Aflatoxin (ng g-1)
Ear rot (%)
x
LH195
x
LH210
x
LH195
.
13
.
4
14
14
2
2
Mp313E_x_Va35Fam58)-2-3-1-1-2-2-1-1
53
24
5
13
Mp313E_x_Va35Fam58)-2-3-1-1-2-1-1-1
.
35
.
10
2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib-B
141
36
5
15
2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib-B
54
51
4
10
.
64
.
6
Resistant Mp715
175
69
4
3
Resistant Tx601
38
72
3
6
PE001n16F2S2-44
27
176
11
10
2283-01_XL380_S11_F2S4_9229-Blk20/00-sib-B
78
.
6
.
7
5
7
8
253
198
9
11
Minimum
14
13
2
2
Maximum
776
623
22
23
Pedigree
Resistant Mp494
Resistant Mo18W/Mp313E
(Mp715_x_Va35)-1-3-3-2-2-1
LSR / LSDα=0.05
Grand mean
x
LH210
Top Resistant GEM Lines Testcrossed to
Aflatoxin (ng g )
Ear rot (%)
LH195 or LH210
-1
Pedigree
Resistant Mp313E
x
LH195
x
LH210
x
LH195
x
LH210
.
.
.
.
Resistant Mp715
175
69
4
3
2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib-B
54
51
4
10
2283-01_XL380_S11_F2S4_9229-Blk20/00-sib-B
78
.
6
.
2258-03_XL380_S11_F2S4_71/97_Bulk/98-sib-B
139
216
8
6
CH1S775:S1911b-16-1-B-B-B
776
.
NC298
.
2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib-B
14
.
141
.
36
.
.
5
15
Resistant Tuxpan
.
.
.
.
Mod Resistant NC300
.
.
.
.
Susceptible NC258
535
399
9
21
7
5
7
8
253
198
9
11
Minimum
14
13
2
2
Maximum
776
623
22
23
LSR / LSDα=0.05
Grand mean
GEM Lines – Yield data
2001 data from 13
(x LH287)
2002 data from 6
Southern Locations Southern Locations
Genotype
2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib-B
Yield
(bu/A)
H2O
(%)
Yield
(bu/A)
H2O
(%)
152.2
16.5
178.8
18.5
184.0
19.0
2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib-B
2258-03_XL380_S11_F2S4_71/97_
Bulk/98-sib-B
160.9
17.6
206.0
20.0
2282-01_XL380_S11_F2S4_9226-Blk26/00-sib-B
149.4
17.8
195.5
20.0
2120-01_DK888_S11_F2S4_9175-Blk28/00-sib-B
173.0
18.8
216.5
20.7
2226-02_XL370A_S11_F2S4_9211-Blk25/00-sib-B
163.0
16.3
203.7
18.9
149.5
18.1
175.3
19.0
2283-01_XL380_S11_F2S4_9229-Blk20/00-sib-B
2142-01_DK888_S11_F2S4_9190-Blk19/00-sib-B
NC258
Commercial Check mean
GEM Lines – Yield data
2001 data from 13
(x LH185Bt)
2002 data from 6
Southern Locations Southern Locations
Genotype
2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib-B
Yield
(bu/A)
H2O
(%)
Yield
(bu/A)
H2O
(%)
152.2
16.5
178.8
18.5
184.0
19.0
2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib-B
2258-03_XL380_S11_F2S4_71/97_
Bulk/98-sib-B
160.9
17.6
206.0
20.0
2282-01_XL380_S11_F2S4_9226-Blk26/00-sib-B
149.4
17.8
195.5
20.0
2120-01_DK888_S11_F2S4_9175-Blk28/00-sib-B
173.0
18.8
216.5
20.7
2226-02_XL370A_S11_F2S4_9211-Blk25/00-sib-B
163.0
16.3
203.7
18.9
149.5
18.1
175.3
19.0
2283-01_XL380_S11_F2S4_9229-Blk20/00-sib-B
2142-01_DK888_S11_F2S4_9190-Blk19/00-sib-B
NC258
Commercial Check mean
GEM Lines – Yield data
(x LH185)
2002 data from 6
Midwest Locations
Yield
(bu/A)
H2O
(%)
148.6
20.2
2258-03_XL380_S11_F2S4_71/97_
Bulk/98-sib-B
139.1
18.9
2283-01_XL380_S11_F2S4_9229-Blk20/00-sib-B
140.4
18.5
2142-01_DK888_S11_F2S4_9190-Blk19/00-sib-B
135.7
19.9
2282-01_XL380_S11_F2S4_9226-Blk26/00-sib-B
137.3
18.5
2120-01_DK888_S11_F2S4_9175-Blk28/00-sib-B
138.6
18.6
2226-02_XL370A_S11_F2S4_9211-Blk25/00-sib-B
135.7
19.0
165.4
18.4
Genotype
2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib-B
2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib-B
NC258
Commercial Check mean
GEM Lines – Yield data
(x LH185)
2002 data from 6
Midwest Locations
Yield
(bu/A)
H2O
(%)
148.6
20.2
2258-03_XL380_S11_F2S4_71/97_
Bulk/98-sib-B
139.1
18.9
2283-01_XL380_S11_F2S4_9229-Blk20/00-sib-B
140.4
18.5
2142-01_DK888_S11_F2S4_9190-Blk19/00-sib-B
135.7
19.9
2282-01_XL380_S11_F2S4_9226-Blk26/00-sib-B
137.3
18.5
2120-01_DK888_S11_F2S4_9175-Blk28/00-sib-B
138.6
18.6
2226-02_XL370A_S11_F2S4_9211-Blk25/00-sib-B
135.7
19.0
165.4
18.4
Genotype
2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib-B
2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib-B
NC258
Commercial Check mean
Testcross Yield Trial 2005
• 145 GEM lines
• 9 public inbred lines
(Mp420, Mp494, Mp715, Mp80:04, Mp717, NC258,
NC298, NC320, Tx601)
• 4 experimental lines from USDA-ARS at, MS State
• 3 commercial checks
(Pioneer Brand P3394, Terral Seeds TV2100, Dekalb
DK697)
• The cross LH195/LH210
Testcross Yield Trial 2005
X LH195
X LH210
MGDU50
to
Silking
MGDU50
to
anthesis
Root
lodging
(%)
Stalk
lodging
(%)
Stay
Green
(%)
Yield
(bu A-1)
Mean
1412
1389
5
4
10
138
LSD
59.0
63.7
16.4
C.V.
3
3
199
155
101
16
3
Minimum
1244
1206
0
0
0
62
11.3
Maximum
1528
1566
46
18
53
192
14.1
Mean
1389
1354
11
10
3
143
12.9
LSD
67.9
72.9
21.9
C.V.
3.0
3.3
120
103
164
18
4
Minimum
1214
1206
0
0
0
85
11.8
Maximum
1537
1517
61
68
38
196
14.2
.
.
.
H2O
(%)
12.9
.
.
0.7
.
.
Continuing Research
W. Paul Williams
Tom Brooks
CHPRRU, MS State
Continuing Research
Pedigree
Resistant
Mp313E
Aflatoxin
(ng g-1)
# of
families
24
(2226-02_XL370A_S11_F2S4_9211-Blk25/00-sib)
128 - 1120
11
(2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib)
24 - 255
6
(2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib)
35 - 589
12
(2258-03_XL380_S11_F2S4_71/97_Bulk/98-sib)
233 - 1348
12
(2283-01_XL380_S11_F2S4_9229-Blk20/00-sib)
157 - 378
7
(357-7DK888S11b F1S2 1428-Blk/02)
190 - 1164
5
(7451-22DK888N11 F2S3 701-Blk/02)
641 - 1989
10
(CH05015:N12-38-1-B-B)
861 - 2142
3
(UR13085:N0215-11-1-B-B)
980 - 1108
2
Susceptible
T173
2307
Susceptible
NC258
2400
Continuing Research
Pedigree
Resistant
Mp313E
Aflatoxin
(ng g-1)
# of
families
24
(2226-02_XL370A_S11_F2S4_9211-Blk25/00-sib)
128 - 1120
11
(2250-01_XL370A_S11_F2S4_9214-Blk21/00-sib)
24 - 255
6
(2250-02_XL370A_S11_F2S4_3363-Blk03/00-sib)
35 - 589
12
(2258-03_XL380_S11_F2S4_71/97_Bulk/98-sib)
233 - 1348
12
(2283-01_XL380_S11_F2S4_9229-Blk20/00-sib)
157 - 378
7
(357-7DK888S11b F1S2 1428-Blk/02)
190 - 1164
5
(7451-22DK888N11 F2S3 701-Blk/02)
641 - 1989
10
(CH05015:N12-38-1-B-B)
861 - 2142
3
(UR13085:N0215-11-1-B-B)
980 - 1108
2
Susceptible
T173
2307
Susceptible
NC258
2400
Thanks!