RESEARCH PROGRAM AND ACCOMPLISHMENTS

Tobacco

Tobacco research has been conducted principally with two of the main types of tobacco, burley and flue-cured. There are so many variations of the ubiquitous tobacco plant under cultivation throughout the world that classification is based chiefly upon the curing method used. All tobacco leaf must be dried or cured before use and the four main methods are flue-curing, air-curing, sun-curing, and fire-curing. Flue-cured tobacco derives its name from the metal flues originally used to distribute heat and carry off the products of combustion in the curing barn or kiln. Burley tobacco is an air-cured type. The history of the industrial development of these two types in Canada is as divergent as the techniques employed for their production or the research programs initiated for their improvement.

The tobacco grown by many of the early settlers of Essex County, which became the tobacco of commerce in the nineteenth century, was a burley type, but apparently not the light-bodied burley favored by smokers in later years. One early writer characterized it as heavy rank tobacco for pipe, plug, and snuff. Mr. Felix Charlan, the first tobacco specialist to be employed by the Canada Department of Agriculture in Ottawa, evidently agreed with this assessment when he laid the plans for the establishment of the Station for the purpose of improving both the quality of the product and the procedures for handling it. Fluecured tobacco was first grown in Ontario in 1906 and in 1913 commercial production commenced with about 100 ac grown at Ruthven in Essex County.

The original experiments at the Station in 1909 included some varietal tests, fertilizer tests, and some demonstrations of cultural practices with both burley and flue-cured types. The first printed record of research appeared in the minister's report for 1912 and indicated that work was continuing with white burley and yellow Virginia. Larger seedbeds with better protection were recommended and a renewal or at least a disinfection of the "mould." Many fertilizers were on the market and it was planned to test all of them. Poisoned bran, which was a mixture of bran, Paris green, and molasses, was recommended as a control for cutworms. Rotations under test included cereal, tobacco, and Indian corn. Clover sown with the grain was plowed under in the spring.

In 1913 new flue-cured varieties in the test included Warne, Virginia, Erzegovine, and Virginia Erzegovine Gigante. The recommended fertilizer for flue-cured tobacco was 3-8-3 at 500 lb/ac. The burley tests had 14 fertilizer treatments, but a severe hail storm damaged the crop so badly that it could not be harvested. About this time considerable difficulty began to be encountered both in the seedbed and in the field in the form of a root rot that affected the whole tobacco growing area as well as the Station plots. Farmers spoke of a burleysick soil and one frequently heard the expression -my ground is burleyed out." Advice on how to deal with this matter included recommendations never to use the same seedbed soil twice, to disinfect with steam or formaldehyde, to change fields, to use longer rotations, and even to apply superphosphate at the rate of 1000 lb/ac. Eventually the root rot was identified by Mr. James Johnson of the College of Agriculture in Madison, Wis., as a disease caused by a fungus called Thielavia basicola . The Station planned to cooperate with Mr. Johnson in breeding for a resistant strain of burley tobacco.

The tone of the experimental program for tobacco had now been set. The work continued, and became a little more elaborate each year. In 1914 eight varieties of flue-cured and four of burley were tested, numerous disinfection tests were conducted, and a moveable scaffolding for harvesting burley was used for the first time. By 1915 the Station was producing a considerable quantity of tobacco seed, the practice of stalk splitting at harvest was tested, and artificial heat was tried in the burley curing barn for the first time. In 1916 the first occurrence of tobacco mosaic virus was reported and an extensive soil study was undertaken. From 1917 to 1922 the Station produced all the seed necessary for the total Canadian production. This seed was cleaned and sampled for germination testing without charge and sold to the growers. It was generally considered that this Canadian-grown seed was superior to imported seed. Fall plowing and early transplanting were now recommended, arsenate of lead was suggested as a control for cutworms and the tobacco hornworm. The only control for mosaic virus was roguing the diseased plants. The variety Burley Resistant offered some protection from disease The recommended fertilizer for flue-cured tobacco was 180 lb/ac of sulfate of ammonia, 400 lb/ac of superphosphate, and 200 lb/ac of sulfate of potash. For burley tobacco the amounts were 400 lb/ac of sulfate of ammonia, 400 lb/ac of superphosphate, 170 lb/ac of sulfate of potash together with 12 tons of manure. Experiments were soon started to compare the effects of applying fertilizer by drilling and by broadcasting.

A considerable volume of experimental data had been accumulated and by 1922 recommendations for improvements in seedbed construction and use were based on the results of 6 years of effort. Similarly a 6-yr experiment had demonstrated the advantage of crop rotation by showing a consistent yield reduction from plots under continuous tobacco. Flue-cured varieties grown were Warne, Hickory Prior, and Gold Leaf. Eleven burley varieties were under test. Researchers were beginning to experiment with the flue-curing process by checking the effects of varying relative humidity and the heat distribution in the kiln. Steam was used experimentally for flue-curing and a large 30 hp boiler was purchased. In 1923 three varieties of the Green River type were introduced; fertilizer tests were greatly expanded to include more than 60 treatments. For 2 or 3 years exceptionally good crops were grown and the effects of root rot were considerably diminished, probably due to a coincidental combination of climatic factors. For a number of years cooperative fertilizer tests were conducted with growers located at points as widely separated as Leamington, Rodney, and Pelee Island, Conclusions as to the amounts of fertilizer required for optimum production of the various types of tobacco coincided closely with the amounts quoted from the Station experiments. Two interesting comments were that sulfate of ammonia was the best source of nitrogen, and many growers felt that home-mixed fertilizers were more economical and effective than the ready-mixed products.

When Mr. Digges left in 1928, he prepared a summary of the 10-yr progress of research during his tenure as superintendent. He stated his assessment thus, "Although marked improvement has been noted during the past 10 years in the cultural methods of a large portion of the tobacco growers, and although there has been a resultant improvement in quality, it is felt that we are not yet producing, on the average, either as high a quality or as large a yield of tobacco per acre as our natural advantages warrant. Further improvement in quality is greatly desired and would undoubtedly result in an increased demand from our home market and would strengthen our hold on our fast-developing export tobacco market." The report gives a detailed summary of the results of all experimental work and a set of recommendations covering every operation in the production process including plant-bed construction, seedling production, rotations, soil preparation, transplanting, fertilizing, cultivation and topping, insect and disease control, harvesting, curing, seed production, and variety selection.

The arrival of Mr. Murwin as superintendent occurred during the period when the tobacco industry was undergoing extensive change. Flue-cured production was becoming relocated in the "new belt" in Norfolk and Oxford counties. The burley business was booming. Production reached a peak of 22 million pounds in 1927, resulting in a glutted market because of a promised export trade that did not materialize. Expansion of the industry was too rapid and overproduction and lower prices resulted. From this time on production declined although the burley acreage in Essex and Kent counties increased by at least 4000 ac in 1930.

A complete reorganization of the fertilizer studies was effected in 1929. A very extensive series of tests was inaugurated for flue-cured, burley, and dark-fired tobacco. A standing committee on tobacco fertilizers was appointed in January 1930 to consider the results of experimental work and to formulate fertilizer recommendations for the various types of tobacco grown in Ontario. The committee was eventually integrated with the Ontario Fertilizer Board and has continued to function to the present time.

A new type of plant bed was introduced at this time, the greenhouse A-shaped bed. Investigation soon showed that more seedlings of larger size could be produced in a shorter period in this house than was possible in the semihot bed or the cold frame, which were in general use. An ambitious experiment was undertaken with a view to classifying all commercial strains and varieties as to type, botanical differences, and cropping potential in Canada. There was no breeding program, but the researchers had a cooperative understanding with certain plant breeders in the United States and continued to examine numerous varieties and strains from various sources particularly for resistance to black root rot. The change in the method of harvesting from stalk cutting to priming eliminated the old flue-cured varieties such as Warne, Hickory Pryor, and Gold Leaf. The flue-cured varieties introduced from the United States that were particularly adapted for priming under Ontario conditions were White Mammoth, White Stern Orinoco, Bonanza, Yellow Mammoth, Gold Dollar, and Duquesne. The priming method of harvesting flue-cured tobacco had resulted in higher yields and improved leaf quality and had reduced the risk of total crop loss due to an early fall frost.

A distinct change had also taken place in varieties of burley tobacco due to a demand by the domestic trade for a thinner, brighter, cigarette burley. The old varieties such as Broadleaf, Broadleaf Resistant, Station Standup, and Standup Resistant were no longer acceptable except for the export market. The continued search for new and better varieties finally paid off with the selection in 1929 of a resistant burley plant that led to the naming and release in 1932 of the variety Harrow Velvet. It was very resistant to black root rot and had many other desirable characteristics that soon led to its becoming the leading burley variety in Canada. Thus began a breeding program that continued for many years and produced a number of outstanding varieties largely through the efforts of Mr. Bob Haslam.

The Substation at Delhi was established in 1933 and although it was administered from the Station, it assumed full responsibility for all research with flue-cured tobacco. All programs were transferred there except variety testing. However, in 1938 the testing of flue-cured varieties was discontinued at the Station except the breeding and testing program for resistance to black root rot. With this exception the program was now directed toward burley and a small effort with dark tobacco.

Fertilizer tests continued to occupy a large place in the tobacco research program. By 1936 recommendations were being made to suit the wide variety of soils used in burley production, and great attention was being paid to individual nutrients as well as the chemical source of each nutrient. For example, it was recommended that one-quarter of the applied nitrogen be from organic sources, one-quarter from nitrate of soda, and the remainder from other standard materials. It was preferable to have a part of the potash derived from muriate because chlorine improves the moisture-holding capacity of the leaf and helps to avoid shattering. The amount must be limited to protect the burning qualities of the leaf and critical percentages of chlorine were recommended for each type of tobacco.

An intensive study of crop rotations was carried on for many years. Recommended rotations depended on the type of tobacco to be grown and the type of soil. It was demonstrated that the proper rotation had an important influence on the maximum yield. Plant spacing, plowing, and cultivation methods were also studied to find the right combination of techniques to get the most benefit from the light sandy soils.

The story of tobacco production in Canada has been one of constantly changing varieties. To meet the demand of a steadily increasing cigarette trade, the trend in tobacco production in southern Ontario, particularly during the years of the Second World War, was toward milder brighter leaf tobaccos. Although large stocks of pipe and chewing tobacco were used during this period, the production of heavy-bodied tobacco was not stimulated to the same extent as cigarette tobacco. This increasing demand for bright tobaccos stimulated the production of the fluecured type. With burley there was a shift from the heavy varieties formerly used for pipe and chewing to lighter standup varieties for manufacturing blended cigarettes and mild pipe tobaccos.

Harrow Velvet may be considered the leader of the cigarette group of burley varieties because with its introduction in 1932 a new class of burley tobacco came into existence. It was one of the first varieties to have an erect growing habit in contrast to the drooping types, which were formerly grown. It had high resistance to black root rot and was a useful variety in the breeding program. Haronova was introduced in 1941 and Harmony in 1945. Both had high resistance to black root rot, high-quality cigarette leaf, and slightly higher yield under average conditions. Resistance to brown root rot had not yet been achieved, but this disease was controlled to some degree by following a proper rotation schedule.

In the years following the Second World War the demand for burley tobacco began to decline and the area in production decreased from 13,200 ac in 1947 to 1096 ac in 1953. However, the research program at the Station was continued in an effort to improve quality and to meet the changing demands of the industry. Fertilizer studies, cultural practices, rotations, and disease investigations were a part of the program. Three new varieties were named and released: Harrow Broadleaf, Haronic, and Briarvet. All three were examples of the heavy-bodied type of burley designed for the export market and each had high resistance to black root rot. But their usefulness to the industry in its current state was limited and they were never widely used.

The only part of the flue-cured research investigation remaining at the Station was the breeding program, and in 1948 it made a significant contribution to the industry with the naming and release of the variety Delcrest, which had been developed by Mr. Bob Haslam. This variety was resistant to black root rot but was susceptible to brown root rot. It produced a consistently high-quality bright leaf and outyielded any flue-cured variety then in use. Delcrest remained the most popular variety for many years and its characteristics were bred into succeeding varieties.

The trend toward thin bright cigarette burley made it necessary to change some of the cultural practices that had been in use for many years. There was now more need than ever to control the rate of water loss during air curing so that it would be neither too slow during wet weather nor too fast during dry windy weather. Mr. Walter Scott started a series of experiments that continued for a number of years using a variety of ingenious techniques to achieve this control. A specially designed calcium chloride dehydrator was built and tested and proved to be very effective. Later, heaters with automatic temperature and humidity controls were used and did an even better job. Subsequently, an automatic, forced, warm-air system with plywood and polyethylene ducts was tested. Each new improvement in the system resulted in higher-quality cured leaf and an increased dollar value for the product. It was observed that on the rare occasions when weather conditions remained favorable throughout the whole curing season, it was possible through judicious control of ventilation to obtain a high-quality leaf product.

Some consideration was given to the method of harvesting burley tobacco. A new method of stalk cutting was tried and found to be advantageous. The tobacco was speared onto the lath and then left to wilt on the standing stick in an inverted position until it was ready to be taken to the curing barn. This procedure caused less bruising of the tender leaves by eliminating much of the handling required in the conventional method. It kept the tobacco cleaner, allowed it to wilt under ideal conditions, and resulted in less damage from sunburn. This technique of harvesting burley has been almost universally adopted. Priming of burley was also tested and was shown to produce a superior quality of leaf, an increased yield, and much higher returns. However, the industry has never seen fit to adopt this method of harvesting even though it would be greatly to its advantage to do so.

During the 1950s a disease called tobacco etch virus caused serious losses in burley tobacco in Ontario and it became the subject of intensive study. It was found to have two insect vectors, the green peach aphid and the potato aphid, and the intensity of the disease fluctuated with the seasonal prevalence of these insects. Numerous burley varieties and lines were screened for resistance to the virus. None was found to be immune, but eventually the Station released a variety that had some measure of tolerance.

In 1963 a new burley variety called Harwin was licensed and released for commercial production. Under test on a range of sandy loam, gravelly loam, and clay soils the yield was 5-10% higher and the quality slightly better than the standard commercial variety of that period, Burley 1. Harwin showed more tolerance for etch virus than Burl, and good resistance to black root rot and brown root rot. It had a lower alkaloid content than other cigarette burley varieties. This represented Bob Haslam's final contribution at the end of a long career in tobacco research and it came a year before his retirement. Harwin possessed many of the desirable features that breeders had been attempting to build into burley tobacco for many years. It was also an answer to a more recent challenge to find a lower nicotine tobacco after it was shown that smoking is a health hazard.

The story of the changing aspect of the burley tobacco industry in Ontario as well as the research at the Station is well illustrated in the following list: