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III. The Sugar Beet in the United States

III. The Sugar Beet in the United States

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SUGAR BEET IMPROVEMENT



97



where they could operate successfully, the sugar beet was grown from

seed obtained from European breeding establishments. I n spite of early

recommendations of the Department of Agriculture and a clear showing, by experiments over a score of years from 1890 on, of the advantage

of home-grown varieties and home-grown seed, the industry, dominated

by European technologists brought over to run the sugar-making equipment, insisted on imported brands. There is no question that the European seed was capable of giving good crops under conditions comparable

to those of Europe, but far too often it was not adapted to conditions

encountered in one area or another in the United States. As we shall

see, the long-continued use of imported seed was at the bottom of much

of the trouble of American factories.

Four major areas are engaged in growing sugar beets, and each of

these has its own special conditions of soil and climate. In the humid

area, sugar beets are grown in Michigan, Ohio, Wisconsin, Illinois,

eastern North Dakota, Minnesota, Iowa, and eastern Nebraska. The

soils used are clays or heavy loams; the crop depends on natural rainfall

which is frequently heavy in the spring months and adequate in most

years in the growing season for good crop production. In the Midwest,

particularly in Colorado, western Nebraska, Kansas, western North

Dakota, South Dakota, Wyoming, and eastern Montana, sugar beets are

grown on heavy soils that are alkaline in reaction; rainfall in spring is

fairly frequent but scanty; and there are occasional summer rains.

This rainfall needs to be supplemented by irrigation and frequently the

crops are irrigated up, since the spring rains do not wet the soils deeply

enough. In the intermountain area-Utah, Idaho, Montana, eastern

Oregon, and Washington-agriculture is confined to sedimentary, valley soils that can be reached by irrigation water, since rainfall is inadequate to produce the crop. On the Pacific coast, in California, the sugar

beet crop is grown on a wide range of soils and under irrigation, the

water coming either from streams or wells. The climate allows the crop

to be grown either as a summer or a winter crop.



3 . The Sugar Beet Threatened by Disease and Insect Attack

Sugar beet culture is limited to acreages within economical transportation distance of a beet sugar factory equipped to carry on the highly

technical process of sugar manufacture. This and other factors have

tended towards intensification of sugar beet culture; accordingly, problems associated with intensified agriculture, especially serious diseases,

have been encountered. In each of the major districts, plant diseases

have been responsible for serious crop failures and, as the industry was

becoming established, were the chief causes of the lack of success of one



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G . H. COONS, F. V. OWEN, A N D DEWEY STEWART



factory after another, bringing about the frequent moves from one place

to another as stable crop production was sought. Thus, the humid area

had a long period of persistently low yields because of black root

(Aphanomyces cochlioides Drechs. and other fungi) (Fig. 1) and leaf

spot (Cercospora beticola Sacc.) . Abundant rainfall, which should have



FIG. 1. Black root of sugar beet. The taproot of the sugar beet plant at the right

is blackened and its lateral roots are killed by the water mold, Aphanomyces

cochlioides. Some measure of the stunting of growth is afforded by comparison with

the healthy plant of the same age on the left. Frequently, affected plants die. (Photograph by J. E. Kotila.)



meant bumper crops, brought about poor stands, low tonnages, and low

sugars (Coons, 1953b). As a consequence, factories were unable to contract adequate acreages in their vicinities.

The Midwest has had serious losses from leaf spot, and, even now,

certain states are experiencing outbreaks of curly top. In the period

1920 to 1940, serious leaf spot epidemics occurred frequently in many

districts, particularly in Iowa, Nebraska, Kansas, and eastern Colorado.



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Often the disease so reduced yield and quality as to make the sugar

beet crop unprofitable to the farmer as well as the factory, and the industry was brought to a low ebb.

I n the intermountain area and in California, curly top, a virus disease that was studied so intensively by Carsner (Carsner and Stahl,

1924), was, over the years, the most serious menace to the sugar beet

industry, almost bringing about the abandonment of the sugar beet

culture west of the Rocky Mountains. In its capacity for producing

injury, curly top ranks with the most destructive plant disease (Fig. 2).



FIG. 2. Sugar beet curly top. Affected plants are stunted, their leaves upcurled,

and the veinlets i n the leaves are enlarged and distorted. A diseased plant, such as

shown, will make little or no growth throughout the entire season.



The virus occurring in range plants is brought to sugar beet fields by

the beet leafhopper, Circulifer tenellus (Bak.). Douglass and Cook

(1954) have published a rksumd of the life history of the beet leafhopper. This leafhopper prefers dry climatic conditions. It breeds on

mustards (Tumblemustard, Sisymbrium altissimum L. and Flixweed

tansymustard, Descurainia Sophia (L.) Webb) , Russian thistle (Salsola

pestifer A. Nels.), filaree or alfilaria (Erodium spp.), and other weeds

that have invaded western range lands deteriorated as a consequence

of overgrazing. These weeds are hosts of the curly top virus.

The vicious cycle of range deterioration, weed invasion, beet leafhopper increase, and curly top epidemics has been outlined by Piemeisal

et a2. (1951). When the vegetation of the range lands becomes dry in



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G. H. COONS, F. V. OWEN, A N D DEWEY STEWART



early spring, swarms of beet leafhoppers, some of them viruliferous,

move into the irrigated valleys. Here the insects feed on the young sugar

beet plants, infecting some of them with curly top virus picked up from

the weed host plants. Each infected sugar beet in the field becomes a

disease center where the insects breed and where nonviruliferous beet

leafhoppers become infectious, and thus they spread the virus. I n years

of high beet leafhopper populations, not a plant in a sugar beet field

escapes infection. Before the development of varieties resistant to curly

top, early-infested fields were, in a few weeks, almost a total loss. Thousands of acres around a factory would be abandoned, and the factory

would have either no run at all or a very short, unprofitable one.

The European varieties grown had no resistance to the diseases that

wrought havoc to American beet crops. Leaf spot and black root occur in

central Europe only sporadically and in mild form. Curly top does not

occur. Obviously, varieties as bred in Europe could not be expected to

exhibit resistance to these diseases.

Such was the situation in the United States at the close of World

War I. The industry had had a precarious existence during the war and

was hampered by shortages of sugar beet seed. All through the formative years, the industry had elected to depend upon imported seed. The

attempts to produce seed in the United States in 1917, 1918, and 1919

were notably too little and too late. They were dropped at the close of

World War I. Then, in the next decade, leaf spot, black root, and curly

top brought disaster to many companies.

IV. BREEDING

FOR DISEASE

RESISTANCE



In 1925, direct attack on curly top and leaf spot by disease-resistance

breeding was started in the Bureau of Plant Industry of the United

States Department of Agriculture. The wild relatives of the sugar beet

were collected in Europe; selection work was started with commercial

sugar beet varieties and with breeders' strains at field stations where

severe exposures to these diseases could be expected each year.

1. Resistance to Curly Top'

The first result of this breeding program was the production of a

variety of sugar beets having some resistance to curly top. Carsner and

Pack (Carsner ef al., 1933) selected vigorous roots from a number of

The breeding of curly-top-resistant varieties was conducted by Eubanks Carsner,

D. A. Pack, F. V. Owen, F. A. Abegg, and A. M. Murphy, assisted in the agronomic

testing by A. W. Skuderna, C. E. Cormany, Bion Tolman, J. 0. Culbertson, H. A.

Elcock, and Charles Price. The investigations were cooperative with the California,

Colorado, Idaho, New Mexico, Utah, and Oregon Agricultural Experiment Stations

and the western beet sugar companies.



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Utah fields in which curly top was causing a decimating loss. Roots that

appeared to be definitely better than the general run of the field were

stored over winter and planted in a seed plot with other roots grown

from similar selections that had been made earlier by commercial companies. A total of 70 to 100 pounds of seed was produced in 1929. The

first test of this seed-later to be designated US l-was made in 1930



FIG.3. The initial test of US 1 sugar beet variety at Castleford, Idaho, in 1930.

Curly top exposure was severe, almost eliminating susceptible sorts. Plot 1703, left

foreground (to the right in front of the man), consists of four rows of US 1. Plot

1704, the four rows to the right, is a nonresistant European brand. In the background, other plots of US 1 and other curly-top-resistant varieties appear as green

“islands.” (Agronomic test by C. E. Corrnany; photographed September 19, 1930

by E. Carsner.)



under conditions of heavy curly top exposure (Fig. 3 ) . AS the photograph indicates, and in comparison with later achievements, the showing made by the variety was not impressive. But the situation of the

beet sugar factories, brought about by curly top, was so desperate that,

with this evidence of some superiority in US 1 over the European types,

steps were immediately taken to make a seed increase from the unused

seed stock as a source of a curly-top-resistant .variety. Details of the

increase and the subsequent multiplications have been given by Coons



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