Breeding Corn Resistant to Diseases
Endemic to the Southern States
Wenwei Xu
Raleigh, NC
February 20-23, 2011
Improving Life through Science and
Technology.
Contributing Scientists
Seth Murray
Gary Odvody
W. Paul Williams
Yingen Xue
Presentation Outline
 Program overview
 Breeding for drought tolerance and CEW
resistance to reduce aflatoxin
 Southern rust
 Fumonisins in the TX High Plains
Breeding Efforts of Corn Breeding Program at
Lubbock Center
Insects - CEW
Drought
Heat
Insects - Mites
Mycotoxins - Aflatoxins
Our Breeding Strategies
Major Issues
Breeding Strategies
▲ Water shortage
►Drought tolerance
► Early maturity
▲ High temperatures
► Heat tolerance
▲ Insects
► Corn earworm resistance
► Spider mite resistance
▲ Mycotoxins
► Grain mold resistance
► Drought/heat tolerance
► Insect resistance
Native Drought Tolerance Genes
• Tropical and exotic germplasm:
 GEM (Germplasm Enhancement of Maize) Project
 CIMMYT
Temperate
Tropical
• Evaluate for drought and heat
tolerance, insect resistance,
grain mold resistance, yield and
other agronomic traits.
 Develop multiple stress
tolerant corn.
Tropical x Temperate
Breeding Drought Tolerant Corn In Texas
• Take advantage of low rainfall.
• Apply precise and uniform amount of irrigation water to impose
drought stress at target growth stages.
• Use subsurface drip irrigation systems.
• Have two fields dedicated for drought study.
• Usually have 2-3 water treatments in a field.
<8
820
2132
453356
44
Average Rainfall in Inches
Drought Stress Symptoms In Corn
Leaf rolling
Shorter plant
WW
Early senescence
Stalk lodging
DRT
Aspergillus flavus
Poor seed set, short ear, small kernel, molded kernels (high aflatoxins)
Yes, severe drought stress can cause total crop loss!
Breeding Strategies For Aflatoxin Resistance
• Improve drought tolerance.
• Improve heat tolerance.
• Improve corn earworm resistance.
• Incorporate aflatoxin resistance QTLs from the
resistance sources like Mp715.
 Develop multiple stress tolerant corn hybrids
that are adapted to the Southern environments.
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
200 400 600
MS 2009
Test mean: 264
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
100 200 300
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
100 200 300
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
100 200 300
MS 2010
LB-WW 2009
LB-DRT 2009
221
167
302
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
100 200 300
LB-WW 2010
274
• Aflatoxin level: consistently low
or high in several hybrids across
environments.
0
100 200 300
LB-DRT 2010
340 ppb
Aflatoxin contamination (% of test mean) of different genotypes of corn at
Mississippi and Lubbock, Texas under drought and well watered conditions in
2009 and 2010.
250
Aflatoxin level: consistently low or high in
Aflatoxin (% of test mean)
several hybrids across environments.
200
150
100
50
0
24 31 29 30 14 1 15 16 18 19 22 4
3 25 12 21 5 20 6
9
8
7 11 10 13 26 23 34 28 17 27 32 33 2
ENO
Average aflatoxin of the 34 genotypes under well-watered and drought conditions
in Lubbock in 2009 and 2010 and in Starkville, MS in 2009 and 2010
Southern Rusts
College Station, TX
Weslaco, TX
Weslaco, TX
Teosinte As a Potential Source of Rust Resistance?

Selfed ears of F1 plants
Open-pollinated ears of BC2F1
plants with 12.5% teosinte
germplasm based on the pedigree.
(SS1 x BSSS:Teo6) x SS2

Selfed ears of the BC2F4 plants
Teo-lines
Disease Resistance and Yield of Teo-line Testcrosses
Hybrids
Teo-Line13 x NS1
Teo-Line20 x NS1
Teo-Line29 x NS1
Teo-Line31 x NS1
Teo-Line33 x NS1
Rust Afla
Weslaco
1.5
3
1.0
237
1.5
216
1.0
51
1.0
505
ET
230
240
235
237
215
Grain yield (bu/a)
HF
HL
CS
248
81
169
244
84
151
231
114
224
206
100
182
232
111
187
WS
128
145
145
137
134
Mean
171
173
190
172
176
Teo-Line48 x NS1
Teo-Line49 x NS1
Teo-Line54 x NS1
Teo-Line62 x NS1
Teo-Line63 x NS1
5.5
1.5
1.5
1.5
1.0
4
0
147
19
260
207
214
241
245
236
237
227
243
250
238
110
106
125
115
116
180
157
171
176
148
147
135
171
154
163
176
168
190
188
180
DKC66-23
DKC67-87
P31G96
P33D49
5.0
4.0
3.0
3.5
157
160
73
281
246
254
258
261
269
274
268
241
98
123
109
105
159
173
182
187
149
165
160
156
184
198
195
190
Test mean of 50 entries
CK mean
CV%
LSD 0.05
2.4
3.9
43.7
2.1
166
168
89
297
225
255
8
38
238
263
8
38
103
109
13
28
172
176
11
36
143
157
9
25
176
192
Fumonisin in Texas High
Plains in 2008
Factors contributing to high
fumonisins:
• Fall armyworm feeding damages
• Common smut
• Loss of kernel integrity
Acknowledgement
We appreciate the financial support from:
• The Texas Corn Producers Board
• USDA-ARS Pre-harvest Control of Aflatoxin Program
• USDA-ARS GEM Project
• USDA Ogallala Aquifer Initiative
•The High Plains Underground Water Conservation District No.1
• Texas Water Development Board
• Industrial support