Grain Yield, Drought Tolerance, and Corn Earworm Resistance of GEM Breeding Crosses Wenwei Xu Agricultural Research and Extension Center Texas A&M University Lubbock, TX 79403

Report
Grain Yield, Drought Tolerance, and
Corn Earworm Resistance of GEM
Breeding Crosses
Wenwei Xu
Agricultural Research and Extension Center
Texas A&M University
Lubbock, TX 79403
Objectives
To characterize the yield potential, drought tolerance,
and corn earworm resistance of 71 GEM breeding
crosses;
To select the best germplasm for developing drought
tolerant and CEW resistant inbred lines.
Materials and Methods
71 GEM breeding crosses: 25-50% tropical germplasm.
Checks: B73xMo17, Pioneer hybrids 34K77 and 3223.
Three water treatments:
Well-irrigation: 16.4 acre-inch irrigation water.
Severe drought stress 1: 5.2 acre-inch irrigation water.
Severe drought stress 2: 7.0 acre-inch irrigation water.
ANTIGO03:N12
GOQUEEN:N16
Nine GEM Breeding Crosses with Above Average CEW Resistance
as measured by CEW Ear Penetration (cm)
Crosses
BG070404:D27
BR51501:N11a
CUBA84:D27
BR51675:D27
ANTIG01:N16
CEW
4.0
4.6
5.0
5.2
5.4
Crosses
DK888:N11a
ANTIG03:N12
DKXL380:N11a 5.1
DK212T:N11a
CEW
4.2
4.8
5.2
Top 15 Breeding Crosses
ANTIG03:N12
AR16026:N12
BG070404:D27
CUBA84:D27
ANTIG03:N1216
PRICGP3:N1211c
BR51403:N16
GUAD05:N06
UR11002:N0308b
ANTIG01:N16
PRICGP3:N1218
CUBA164:D27
CH05015:N1204
BR51501:N11a
BR51675:N0620
ANTIG03:N12 yielded well under irrigated and drought stressed
conditions, and had good CEW resistance, low grain mold, good stay
green trait, upright leaves, and good husk coverage.
Control of Aflatoxin by Improving Drought Tolerance in Corn
Wenwei Xu1 and Gary Odvody2
1. Texas A&M University Agricultural Research and
Extension Center, Route 3, Box 219, Lubbock, Texas 79403
2. Texas A&M University Agricultural Research and
Extension Center, 10345 Agnes Street, Corpus Christi, Texas
78406
Drought and heat tolerant corn have less grain molds under
drought stress. We believe that the primary reason for high
aflatoxin in southern environments is the lack of commercial
corn hybrids specifically adapted to this region. This study
tested our hypothesis that genetic improvement of stress
tolerance can reduce the aflatoxin risk in Southern
environments.
Lubbock
College Station
Corpus Christi
Kernels colonized by a high aflatoxin-producing isolate of A. flavus
(NRRL3375) were distributed between rows of each plot when the first
hybrids were at mid-milk stage to provided uniform aerial inoculum for
infection.
Aflatoxin level in ppb (Mean SD) of the experimental hybrid
CML343xTx202 and two check hybrids under inoculated field
at Corpus Christi in 2000, 2001 and 2002.
Entry
CML343xTx202
P31B13
2000
2001
2002
Aflatoxin
12027
20783
20781
Log (afl)
4.80.2
5.30.4
5.300.4
Aflatoxin 703185 25331168
660252
Log (afl)
6.50.3
7.80.5
6.40.4
Aflatoxin
6027
17721
13010
Log (afl)
4.00.4
5.20.1
4.90.1
Aflatoxin
398
1276
849
Log (afl)
5.8
6.9
6.5
Aflatoxin
60-767
177-2533
130-1303
CV% for Aflatoxin
38.6
55.5
41.6
LSD 0.05 for Log(afl)
0.6
0.8
0.7
DK XL269
Test Mean
Test Range
Ears of CML343xTx202 at Corpus Christi in 2000.
Conclusions
CML343xTX202, an experimental hybrid developed by
TAES-Lubbock corn breeding program, had 69% to 92%
lower aflatoxin content than the check Pioneer hybrid
31B13 under A. flavus-inoculated field conditions over
three years.
Drought tolerance, good husk coverage, and low
insect injury on ears may contribute to the low aflatoxin
in CML343xTx202.
Results indicate that breeding for drought tolerance
and earworm resistance is a promising approach to
reduce aflatoxin contamination in corn grown in
Southern environments.

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