Corn earworm resistance in sweet corn inbreds and hybrids

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Material Information

Title:
Corn earworm resistance in sweet corn inbreds and hybrids
Physical Description:
22 p. : ; 27 cm.
Language:
English
Creator:
Walter, E. V ( Elmer Valentine ), 1891-
United States -- Bureau of Entomology and Plant Quarantine
Publisher:
U.S. Dept. of Agriculture, Agricultural Research Administration, Bureau of Entomology and Plant Quarantine
Place of Publication:
Washington, D.C
Publication Date:

Subjects

Subjects / Keywords:
Helicoverpa armigera -- Control   ( lcsh )
Sweet corn -- Insect resistance   ( lcsh )
Genre:
federal government publication   ( marcgt )
non-fiction   ( marcgt )

Notes

Statement of Responsibility:
by E.V. Walter.
General Note:
Caption title.
General Note:
"E-745."
General Note:
"April 1948."

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030297855
oclc - 780429371
System ID:
AA00025200:00001

Full Text




April 1948


United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine



CORN EARWORM RESISTANCE IN
SWEET CORN INBREDS AND HYBRIDS

By E. V. Walter
Division of Cereal and Forage Insect Investigations


Much effort has been made during the past several years to find in-
breds and hybrids of sweet corn resistant to the corn earworm (Heliothis
armiera Hbn.). This work has been done in cooperation with the sweet
corn breeders of several State agricultural experiment stations and the
Bureau of Plant Industry, Soils, and Agricultural Engineering of the U. S.
Department of Agriculture._/ Some of the information obtained has been
assembled in this paper for the convenience of plant breeders and ento-
mologists interested in corn improvement.

The following tables show the general reaction of some of the inbreds
and hybrids tested. Many experimental inbreds and hybrids, including some
of those listed in the tables, have been discarded because of agronomic or
other weaknesses. Most of those discarded reacted as intermediate or
susceptible to earworm injury, although a few that were poor agronomically
appeared to have a rather high degree of resistance. Inbred selections
in some of these are being attempted.


I/ Seed used in these tests has been furnished by W. Ralph Singleton,
Connecticut Agricultural Experiment Station; Walter A. Huelsen, Illinois
Agricultural Experiment Station; E. S. Haber, Iowa Agricultural Experiment
Station; J. B. Park, Ohio Agricultural Experiment Station; Glenn M. Smith,
U. S. Bureau of Plant Industry, Soils, and Agricultural Engineering and
Purdue University Agricultural Experiment Station; Charles F. Poole,
U. S. Bureau of Plant Industry, Soils, and Agricultural Engineering,
Charleston, S. C.

In addition to the material furnished by the several breeders, a few
varieties and hybrids have been purchased in the open market for testing.
A few selections made by the writer and a few made in cooperation with
R. A. Blanchard of this Bureau and R. 0. Snelling of the Bureau of Plant
Industry, Soils, and Agricultural Engineering are included. A number of
experimental crosses between tested inbreds have been made by members of
these two Bureaus for our studies on inheritance of resistance. These
are included in table 3.


, V
' I" '


E-745






-2-

The reaction of many of the strains to natural infestation was
observed at Weslaco, Tex., where a heavy and quite uniform infestation
could be expected each year. At Lafayette, Ind., and Urbana, Ill.,
where there was less likelihood of a uniformly heavy infestation, the
natural infestation was supplemented by the placing of 3 newly hatched
larvae on the silks of each ear 3 to 5 days after emergence, and 3 more
similar larvae on the silks of the same ears 2 to 3 days later. The
damage was usually appraised at the roasting-ear stage after the larvae
had left the ear.

Most varieties reacted the same to the natural infestation as they
did to the artificial or supplemented infestation. There were a few
exceptions, however, the most notable of which was inbred P53, which was
highly resistant to natural infestation wherever tested, but reacted as
a susceptible when the larvae were placed on the ears under the selfing
bags. It reacted as a susceptible when used in crosses. Egg counts
showed as many eggs on P51 as on other inbreds. Such exceptions are
noted in table 1.

After the larvae had matured, the ears were gathered and husked to
evaluate the damage. The infested ears were placed in 5 classes, accord-
ing to the amount of feeding done, as follows: Class 1, tip only; class
2, kernels to j inch below the tip; class 3, kernels to 1i inches below
the tip; class 4, kernels to 2J inches below the tip; and class 5,
kernels exceeding 2J inches below the tip. Butt or side injury was
placed in one of the above classes, depending on the location and amount
of trimming necessary to make a usable ear. The percentage of ears in
each class could then be determined. Counts of the injured kernels on
several thousand ears, after dividing into classes as described above,
showed the number of average-size kernels destroyed to be approximately
as follows: Class 1, less than 1; class 2, 10; class 3, 20; class 4, 30;
and class 5, 40. Multiplying the percentage of ears in each class by the
average number for the class and adding the products gave a sum which
tests have shown to closely approximate the actual number of average-size
kernels destroyed per 100 ears. This sum, or injury index number, can be
directly compared with that of another sample to show which is the more
resistant.

The injury index number varied slightly from one test to another
within the same variety. Since some of the varieties listed in the
tables were tested as many as eight times, the index number is not given.
It was used, however, in compiling the tables, and the variety was listed
as resistant, intermediate, or susceptible, with supplementary notes to
denote the highly resistant strains. A strain was considered resistant
or susceptible in our tests according to whether its injury index number
fell below or above the median one-third for all strains in the test.








The factors responsible for resistance are not well understood. The
tables show, however, that with few exceptions the degree of resistance
found in a single cross is in proportion to that found in the inbreds.
The plant breeder may be able to combine two or more of the known resist-
ance factors to produce superior inbreds and hybrids. Many of the inbreds
listed in table 1 have been tested in several crossed, so that we have some
indication of their reaction in breeding. See tables 2 and 3. Where
enough crosses have been tested, the reaction is shown in the "Remarks*
column in the table.

Many additional lines have been tested for earworm resistance but
have been dropped from the breeding programs for various reasons. A few
other lines that have been discarded by the originating breeders are
listed in the tables, because they may still be under test by other
breeders and cooperators.

A few open-pollinated varieties and a few hybrids produced by
commercial breeders were purchased in the open market and tested.
These varieties are shown in table 4.

About 90 inbreds and hybrids of popcorn have been tested for earworm
resistance. Consistent differences in the reaction to earworm injury
have been noted in many of those tested, but so far none have shown a high
degree of resistance. They are not listed in this paper.

The reactions and resistance of sweet corn inbreds and hybrids to
corn earworm injury follow.


- 3 -






-4-


Table l.--Reaction to earworm injury and present status of sweet corn inbred
tested for resistance to the corn earworm.


Yellow Inbreds


Illinois
59,
60b
62a
64b
66a
O7a
68a
?0a
71a
72a
72b
72c
73a
73c

74a
75a
76a
76b
76d
78a
80a
80b
82a
83a
84a
85a
85b
85c
85d
85e
86a
86b
86c
86d
86e
86f
87a
87b
89a
91a
92a


D
D
I
N
5
D


z
D
2
I
RC
z
z
z
I
X


R

z
z
D
D
E
D
D
1
D
D
2
D
D
D
z
z
I
z
D
D
D
z
z
I
D
z
z
R
z
E
R


Breeds moderate resistance.

Breeds susceptible.

Breeds moderate resistance.
do.
Crosses test as other parent.


Breeds moderate resistance.
Used in Golden Hybrid No. 10.


Breeds moderate resistance.


Breeds intermediate.

do.




Breeds susceptible.
Breeds moderate resistance.

Breeds susceptible.

do.
Breeds moderate resistance.
do.

Breeds susceptible.

Breeds intermediate.
do.








Table 1.--(Continued)


-5-


Yellow Inbreds


Illinois
93a
94a
95a
96a
97a
98a
98b
99b
0lla
lOlb
lOlc
lOld
101e
lOlf
lOlh
lOlj
1011
lOln
lOlq

101r
lOls
101t
lOlu
lOlv
101w
lOIx
lOly
101:
alOl
dlOl
1eO1
flOl
glOl
103a
103b
103c
103d
103e
103g
103h
103J


Breeds resistance.





Breeds very susceptible.

Breeds intermediate.




do.

Breeds moderate resistance.
Used in Golden Hybrid No. 10.


Breeds moderate resistance.





Breeds intermediate.

Breeds susceptible.


Breeds intermediate to susceptible.
Breeds moderate resistance.






-6-


Table 1.--(Continued)


Yellow Inbreds


Illinois
103k
1031
103m
103n
104c
104d
104e
104f
104h
104J
104k
1041
104m
104q
105a
106a
106b
107a


Breeds moderate resistance.


One of most resistant yellow
inbreds. Crosses test as
other parent.


107b
108a
108.
108f
108g
109a
llOa
110d
110f
llOg
110h
o110j
lila
lllb
112a
112b
112c
112d
112e
112f
112g
112h
112j






-7-


Table l.--(Continued)


Yellow Inbreds


Illinois
113a
113b
113c
113d
113.
113f
113g
113h
113J
113k
1131
114a
Indiana
P14
33A-1
35(6)1
35(6)2
35B
P39
P39A
P39B
P39C
P39-10


Breeds susceptible.



do.
do.
do.


R Early, diminutive P39 selection.
Breeds susceptible.
R Resistant to natural infestation
only. Breeds susceptible.
R do.


One of most resistant yellows.


P51


P51B
268
299
336
353
354
357
621
655
661
662
664
667
685
686
687
688






-8-


Table 1.--(Continued)


Present
Number of Testa Status
Source and Resist- Inter- Suscept- of
Inbred Number ,ant mediate ible Inbred- Remara-


Yellow Inbreds


Indiana
695
703
724
1308
1313-1-1
1313-1-2
Lal(3)l
Lal(3)3
Lal (3)23
Lal(3)221
La2(3)3
La2(3)l
L2 (3)21
Le2(3)32
La2(3)52
Iowa
IP39
145
60
467
2019
2021
2052
2067
2174
Wx2153-1
2000
2166A
5055
6014
051K2A
Ohio
1l3
26
28
29
39Kl
39K3
51K1
51K2-115


Breeds susceptible.


Reacts
Breeds
Breeds
Breeds
Breeds


similar to P39.
moderate resistance.
susceptible.
resistance.
moderate resistance.


Breeds resistance.
do.
Highly resistant Ia 4 combination
do.
Intermediate in 3 combinations.
Resistant in 2 combinations.
Resistant in 1 combination.

Breeds resistance.






Used in Ohiogold 1, 2, & 4.






-9-


Table l.--(Continued)


Yellow Inbreds


51K2-123
51K2-Scharff
E51
52
94b
G192-74
B3&PQ
Laf


E Breeds resistance.


Country Gentleman Inbreds


Illinois
if


R Breeds intermediate. No longer
used. Discarded.
R Breeds susceptible. No longer
used.
R No longer used.
R No longer used. Discarded.
R do.
R No longer used.
R Very resistant. No longer used.
R Original release. Breeds
intermediate.
D
R Present selection used in
Illinois 5 x 10.
I
E
D
D
D
E
E

D
I
E
R Used in Illinois 5 x 10.


5k
51
5w
5x
b5
d5
g5
h5
J5
k5
15
6a
6h
6j
6k
61
6m
6n


I






- 10 -


Table l.--(Continued)


Source and
Inbred Number


Number of Tests


Present
Status


Resist- Inter- Suscept-i of
ant mediate ible I InbredN


Country Gentleman Inbreds


Illinois
8c


R Used in Illinois 8 x 6. Breeds
susceptible.


Breeds susceptible.



Original release.



Breeds susceptible.









Not used at present.


Used in Illinois Hybrid No. 13.


8d
8e
8f
8g
8h
8j
8k
81
8m
lOa
10d
100
lof
lOg
10h
lOj
101
1On
lop
10q
lOr
lOe
l5b
15h
18a
18b
19a
19b
20a
21a
21b
21c
21e
22a
24a
24b
24c
24d
24e


II I [[[[ I I I I


a ......


A


Remarks2






- 11 -


Table l.--(Continued)


Present
Number of Tests Status
Source and Resist- Inter- Suscept- of J2
Inbred Number ant mediate ible InbredA Remarks2J


Country Gentleman Inbreds


Illinois
27a

28a
29a
31a

31b
32a
34a
35a
36b
38a
39a
41a
42a
43a
44b
45a
46b
46c
47a
48a
48b
50a
200d
200f
200k

Indiana
FRI
FR14
FR34
10
22-2
29
30(17)1
347

348
534


R Breeds resistance. Used in
Illinois Hybrids Nos. 13 & 14.
E
D
R Breeds intermediate. Used in
Illinois Hybrid No. 14.
E
D
E
E

E
z

z
K
E
E
2

R Used in Illinois Hybrid No. 15.
E


R Used in Illinois Hybrid No. 15.


Highly resistant.
susceptible.


Breeds


Breeds moderate resistance.

do.


Breeds very long ear.
Some resistance.






- 12 -


Table l.--(Continued)


Present
Number of Tests Status
Source and Resist- Inter- Suscept- of
Inbred Number ant mediate ible Inbredl Remarks2-


Country Gentleman Inbreds


Indiana
732(5)KU
6267
6355
6532
6609
6684
7212
7685
7710
8035
8065
8098
8111
8203
8225
8339
8344
Iowa
1445
1627
2508
2730
4011


Breeds susceptible.


Breeds resistance.






do.


E Highly resistant. Crosses test
as other parent.
E Highly resistant. Crosses test
as other parent.


4024A

4040
4060


Evergreen Inbreds


Illinois
lla
lib
lic
lid
lie
13b
13c
13d


Original release.


Used at present.






- 13 -


Table l.--(Continued)


Evergreen Inbreds


Illinois
13h
14a
14b
14d
14g
14h
14k
141
14m
14n
14p
52a
55a
55b
55c
55d
55e
57a
57b
58a
Indiana
119
651(3)1W
1009-8
1014
7600
8449
Bl-1
Bl-21
Iowa
3001
3002
3005
3006
3044
Ohio
22G
40
42
44
45
AM-1-1-1


R Original release.
D
E
R Used at present.
D


Very resistant. Breeds resistance.


Original release.





- 14 -


Table 1l.--(Continued)


Evergreen Inbreds


BPISAE-South Carolina
2d-2d-Od (Sel)

2d-2d-ld(Sel)
26-8-3-7a-l-l
26-8-3-7a-5-2
53-4a-l-l-2-2
80-11-5b-5a-l-2b
81-1-3-3-2-11
B&PQ & BPISAE (coop,)
241-Ul-U3-Ul-B
471-U6-Al-U2
471-U12-U3-B
471-U12-U5-B


E Very resistant. Brooeeds
resistance.


I Breeds resistance.


do.


g Present status of the strain as given by the brooeeder.
E experimental, R released to commercial trade, RC release
contemplated, D discontinued or discarded by originating breeder,
may still be carried by others.

/ Remarks concerning resistance and breeding for resistance should be
credited to the writer. All others should be credited to the
breeder who supplied the seed.








- 15 -


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UNIVERSITY OF FLORIDA
-22-
3 1262 09239 2058
Table 4.--Reaction to earworm injury by commercial varieties
and hybrids tested for resistance to the corn earworm.

I Number of Tests
Variety Resist- Inter- Suscept-
.. ........ant mediate ible

Aristogold Bantam 2 -
Aristogold Bantam Evergreen 1 1 -
Aunt Mary's Sweet 2 2
Golden Grain 1 -
Honey June 2 -
Hybrid Stowell's 1 -
Mosehart Sugar 2 -
Oregon Evergreen 2 2 -
Papago Sweet 2 -
Stowell's Evergreen 1
Surecropper Sugar 1 1 -
Sweet Snowflake 1 1
Texas Evergreen 2 -
Top Flight Bantam 2 -
Tri State 1 -
U534 3 -