VI. Tests of Inbred Strains for Disease Resistance
Last spring seed of five inbreds furnished by Wiggans, one by Hayes, one by Kvakan, three by Bryan, and five by Singleton were sent to eight cooperators in various parts of the United States. The severe drouth and heat in some areas made possible a good comparison of the inbred lines in regard to resistance to firing.
The following tables and supplementary notes on the inbreds were received by the Co-op:
Arlington Experiment Farm, Rosslyn, Virginia -
|Co 206||7/30||27||3||0||Very little pollen|
|Co 208||7/26||34||13||0||Good line|
|Co 211||7/26||33||21||0||Pollen 5 or 6 days later than silks|
|Dr 276 A||8/10||30||9||0|
|WD 456 A2||8/2||23||22||1||Very good line|
|Kvakan 6991||7/30||9||2||0||Light green & spotted No good here|
|Singleton||C2||25||0||Too early. Entirely unsuited to Arlington conditions|
M. T. Jenkins
Ames, Iowa -
The season in Iowa was so unfavorable that observations must not be taken too seriously. Early lines were more affected by these conditions than the later lines. No attempt was made to hand-pollinate any ears. Under open-pollination the set of seed was fair on some lines and poor on others.
The season was good for testing smut resistance, the smut infection being about as heavy as in 1935. The following notes were made on the inbred lines:
A. A. Bryan
Columbia, Missouri -
|Co 214||yellow green in color; no ear shoots|
|S 283||tassels were blasted on 7/6; first silk appeared 7/9|
|Co 206||wilted badly followed by firing and tassel blasting; tassels blasted 7/15|
|Co 208||little firing but tassels blasted 7/15|
|Co 210||little firing but tassels blasted 7/16|
|Co 211||upper leaves fired; tassels blasted 7/9|
|Kvakan 6991||very slender stalk; yellow green color; tassels blasted 7/9; first silks 7/11|
|Dr 276 A||lower leaves fired 7/17; pollen shed 7/17|
|WD 456 2A||silked 7/13; all tassels blasted by 7/17|
|Bryan 234||upper leaves fired 7/15; first silks 7/20|
No rust, bacterial blight or smut was noticed in these cultures. None of the strains produced ears.
G. F. Sprague
Durham, North Carolina -
|Approximate order of adaptability||
Number of diseased
|Group I (good)|
|1.*Dr 276-A||0||0||late||general appearance sturdy|
|2.*Co 208||0||13(50%)||med.||Rust injury negligible|
|4.*WD 456-A2||0||0||med.||two plants runty|
|Group 2 (fair)|
|5. Co 210||0||0||med.||seg. small plants|
|6. Kvakan 6991||0||0||med.|
|7. I 234||1(5%)||0||late|
|Group 3 (poor) (not in order)|
|C 85||1(5%)||0||med.-late||Two "F1 hybrids" ruled out.|
|#Co 211||0||0||med.||General appearance satisfactory|
|Co 214||0||0||med.||Very few seeds on open-pol. ears|
|Co 206||0||0||med.||Not much pollen; probably protandrous|
* eight to 20 hand-pollinations in each of these inbreds.
# all pollination failures were of same date. This inbred may deserve better rating.
Conditions prevailing here last summer were in general too favorable to afford a rigorous test. The weather was consistently hot but rainfall was adequate (for late plantings which included these inbreds). No firing, no lodging, and no bacterial blight was observed. The infrequency of smut and rust infection in the inbred lines may not mean much, since my cultures generally suffered little from smut rust.
I had occasion to use some of these inbreds in crosses and also made a few self and sib pollinations in each line. The rating as to adaptability is based largely on the results of these pollinations. The proportion of successful pollinations and the yield of grain resulting provided a basis for rating.
H. S. Perry
Morgantown, West Virginia -
|Bryan 276 A||44||24||12||fair||0||39||Very short ears|
|" 234 *||70||0||0||v. good||0||25||#1 of Iowa lines, late|
|" 456 A2||65||0||0||v. good neck||10.3||29||#2 of Iowa lines,|
|Co 206||53||72||9||fair neck||7.7||13|
|Co 208||50||0||0||v. good neck||7.7||13|
|Smut check||gen'l 26.3||19|
|" 211-10⊗||45||0||0||good||ear 3.8||52|
|" 212-18⊗||5||20||15||fair||below ear 1.5||66|
|" 210-11⊗*||64||15||10||fair+||ear, neck 3.4||59|
|" 209-13⊗||46||70||0||----||0||10||stalks break down early|
|Smut check||gen'l 54.9||51|
|Wiggans 208-9⊗||58||5||5||good||0||47||stalks break down early|
|Singleton C78, C 13, C 85, C 2, C 6||Planted late and on different plot, no smut. May be able to run this 1938|
* These are considered the best lines.
C. R. Burnham
Ithaca, New York -
|Inbred line||Smut||Rust||Ears||Maturity||Plant Type|
|Co 206||Some ear smut||1||fair||med.||weak stalk|
|Co 208||Badly smutted||2||poor||med.||very desirable|
|Co 210||Moderate amt.||2||poor||med.||slender stalk|
|Co 211||Trace||1||good||med.||sturdy plants|
|Co 214||0||2||good||early||sturdy plants|
|S 283||0||3||fair||med.||very weak|
|WD 456-A2||Trace||1||good||late||rel. sturdy|
|Dr. 276A||0||1||good||late||short, sturdy|
|I 234||Trace||1||good||late||rel. sturdy|
|Kvakan 6991||Moderate amt.||4||v. poor||med.||lodged badly|
(Rust notes taken latter part of Sept., rating is 1-5)
No bacterial blight and very little firing.
Inbred Co 211 is the most desirable one of this group for Ithaca. It excells in the favorable combination of suitable maturity, resistance to smut, good plant type, good ears, and vigor. It did show some top firing, however.
Co 208 has excellent plant type and proper maturity but it has much tassel and ear smut. Bryan's inbreds Dr 276A, I 234, and W.D. 456A2 are eliminated only because of maturity. They are too late for Ithaca.
D. G. Langham
A general summary of the above tables approaches impossibility, and may not be desirable, anyway, because certain inbreds are best adapted to certain localities. We note, however, that inbreds WD 456-A2, Co 208, Co 211, and S 283 met with the greatest approval and should be included in the test another year. Perhaps inbreds Dr 276A, I234, Co 210, and Co 206 should also be tested further.
Several of the cooperators in this test of inbred lines for disease resistance have suggested that a uniform system of taking notes on the different inbreds be established. What is your opinion in the matter? If those of you who are interested will send to the Co-op. the type of form that you prefer for this purpose, we will attempt to combine the best suggestions into one blank to be used in 1937.
Any of you who would like to conduct this test on disease resistance in 1937 will please notify us soon. If you have some inbreds that are quite resistant to disease and have desirable plant type, we should like to include them in the test this year. There is, of course, a limit to the number of inbreds we can handle properly.
(D. G. Langham)