Wolf Prize in Agriculture (1157 Pages)

John C. Walker

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The few cabbage plants that could survive the disease were interesting to these

men. Healthy plants from the most severely infected field were to be selected for

seed production — stored over winter and replanted the following spring. Three

plants were selected from a field of over 25,000, they were carefully stored and

replanted in the same infected field of Matt Broesch. One night Mr. Broesch’s cow

got loose and partially destroyed two of the plants! The cabbage industry was

saved, however, by that single plant that was spared.

John Charles Walker was born on July 6, 1893 in a house on Lathrop Road

that still stands just north of  21st Street. He entered Beebe grade school, attended

Racine High School where he graduated with the highest scholastic record of any

boy in his class. In 1910 he entered the University of Wisconsin. In the spring of

1912 he went to Dr. L. R. Jones and stated that he thought he would like to major

in plant diseases, the new science recently named Plant Pathology. Dr. Jones’ answer

to this was, “That is fine, Charley. You have quite a problem in your own backyard,

a disease in cabbage that we know very little about. You can start working on that

this summer during your vacation” — and for more than 45 years J. C. Walker has

been working with cabbage.

RESEARCH CONTRIBUTIONS TO WISCONSIN

Wisconsin is a giant among states in the production of vegetable crops for fresh

market and processing. It leads all states in production for processing of peas,

sweet corn, beets, and carrots. It is second in production of cabbage for sauerkraut,

and cucumbers for pickles. It is a leader in production of onions (both sets and

bulbs), potatoes, beans, and lima beans.

ACCOMPLISHMENTS

Cabbage

Seed of  the first yellows-resistant variety of  cabbage, Wisconsin Hollander

No. 8, was being increased locally as rapidly as possible. Slightly less than

100 pounds were produced in 1916, hardly enough to meet the needs of the local

growers. Seed production in 1917 exceeded 800 pounds. (In 1957, forty years

later, total production of yellows resistant cabbage seed in this country exceeded

135,000 pounds!) At this critical time another disease, Blackleg hit Wisconsin.

This was a disease that was transmitted from one crop to another through seed,

unlike cabbage yellows which was soilborne. The success of the new yellows-

resistant program was doomed unless blackleg could be controlled. J. C. Walker

was handed this assignment and in short order he had the disease under control.

He showed that if cabbage seed was produced in the Pacific Northwest instead of

in Wisconsin it was disease-free. This not only saved the day for the cabbage

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Wolf Prize in Agriculture

industry in Wisconsin but was a prime factor in the shift of the cabbage seed

industry from Northern Europe to the United States.

Walker next turned his attention to the yellows disease which had been brought

under control by the development of the Wisconsin Hollander No. 8 variety. This

variety was only partially resistant and was not suitable for all uses. Walker

discovered a more desirable type of resistance and has given to the growers some

12 or 15 different varieties of  resistant cabbage.

The Clubroot disease of cabbage is as ancient as the crop and control of  it has

defied man through the centuries. Walker turned his plant breeding skill to this

problem and has developed resistance to it. He took resistance from curly kale and

transferred it to cabbage. Control of this most serious disease is now certain.

1914. Same field, the first yellows resistant

strain of cabbage. In the background,

right to left, the student J. C. Walker,

Dr. L. R. Jones and W. J. Honsche.

In recent years kraut manufacturers in Wisconsin have been deeply concerned

about a disease called Tip-burn. This disease occurs in lettuce also and results in

shreds of dead tissue in both crops. Walker is now working on this problem and is

on the track of a way to control it.

Onion

Walker did some of the early work showing the effect of artificial heat on the

drying of  onions in storage and the relationship of their preservation to disease

control. This work was done about 40 years ago. With the recent change in onion

production, mechanical harvesting and storage in bulk, with large amounts of air

being forced through these bulk piles of onions, every grower today is referring to

Dr. Walker’s paper and is using heat to cure and control the diseases of onion in

storage. He made the original technical descriptions of two of the neckrot diseases.

Smut is Wisconsin’s worst disease of onions. Our basic knowledge on the effect

of soil temperature on the occurrence of this disease was made by Walker. He took

the idea of dripping formaldehyde solution on the onion seed as they are planted

and worked out a practical application that saved the onion industry in Wisconsin.

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John C. Walker

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Onion smudge is a disease of white but not of yellow or red onions. Walker

showed that the pigments that form the yellow color in onions acted as a chemical

substance forming resistance to smudge in onions. White onions, without this

chemical substance, are susceptible to smudge. This is the most classical piece of

research on the nature of resistance due to chemicals that has ever been worked out.

Walker was instrumental in starting a national program for the development

of onions resistant to pink root, a disease of increasing importance in Wisconsin.

Peas

The story of peas differs little from that of  cabbage. Pea wilt was ravaging the

fields of southern Wisconsin. Walker tested some 250 varieties of peas and found

some to be naturally resistant. With Professor E. J. Deiwiche, he developed resistant

varieties suitable to Wisconsin’s needs. Today, Wisconsin’s 150,000 acres of peas

are planted to these resistant varieties.

Beets

As Wisconsin’s beet canning industry developed, it was faced with a serious disease

known as black spot or heart rot. This disease was shown to be due not to a

parasite but to a lack of boron in the soil. Walker showed that the disease could be

controlled by adding boron in minute amounts to the soil or by spraying it on the

leaves.

A few years ago Wisconsin’s great pickle industry was threatened with extinction

by epidemic occurrences of the scab disease and by severe losses from the mosaic

disease. Walker crossed a scab-resistant slicing variety with a mosaic-resistant

pickle variety and developed varieties of the pickle-type resistant to both diseases.

These varieties are saving Wisconsin’s agriculture over one million dollars each year.

This picture shows the difference between

the death and survival af  an annual 2½

million dollar industry which is directly

attributable to the work of  Dr. John

Charles Walker.

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