THE BREEDING WORK of the U.S. Department of Agriculture, with the varieties and techniques developed there, is of importance, but no account of strawberry breeding is adequate without a description of the work conducted for the past forty-five years by the research stations of the United States and Canada. What follows is such a description, including brief accounts of the experiment station work and some material about originators of important varieties. This account is not intended to be exhaustive by any means, but it should indicate where breeding work is, or was, conducted, how extensive the work is and toward what goals it is directed. For the breeder, knowledge of the work pursued by contemporaries, especially the material, objectives, and progress of their programs, can be very helpful, for it may serve to persuade him to initiate some projects and to put aside others, which evidence seems to indicate as holding little value.
In the United States, research stations concerned with strawberry breeding are located in Alaska, California, Oregon, and Washington, in the far West; Wyoming, South Dakota, Minnesota, Iowa, Missouri, Texas, Louisiana, Mississippi, Tennessee, Kentucky, Wisconsin, Michigan, and Illinois in the mid-West; Florida, North Carolina, Maryland, New York, New Jersey, Vermont, New Hampshire, and Maine in the East. Important varieties have resulted from the work of:
|Schwartze and Myhre, Washington||Northwest, Columbia|
|Darrow, Scott, Waldo, & Meader, U.S.D.A.||Blakemore, Fairfax, Midland, Dixieland, Earlidawn, Pocahontas, Surecrop, Midway|
|Waldo, Oregon & U.S.D.A.||Siletz, Mollala|
|Thomas & Goldsmith, California||Shasta, Lassen, Goldsmith|
|Bringhurst & Voth, California||Solana, Fresno, Torrey, Tioga|
|Hawthorne & Miller, Louisiana||Klonmore, Headliner, Dabreak|
|Henry, Tennessee||Tennessee Beauty|
|Slate & Watson, New York||Catskill, Erie, Empire|
|Brooks, Florida||Florida Ninety|
|Morrow & Darrow, North Carolina & U.S.D.A.||Massey, Albritton|
|Clarke, New Jersey||Sparkle|
|Gilbert, Moore, Hough, New Jersey||Jerseybelle, Vesper|
Of today's important varieties, only the Robinson, Marshall, and Howard 17 (Premier) have not come from experiment station work and all are rapidly becoming less important.
The first actual breeding work by an experiment station in the United States was that begun at the New York Station at Geneva in 1889. The early work in New York was intermittent, however, and although some 12 varieties were originated and named by 1917, none became important. Soon after 1900 however, Hansen (1907), of South Dakota, and Georgeson (1910), of Alaska, learned that hardy varieties could be originated through breeding, and by 1917 Anthony (1917), of the New York Station, saw that promising varieties could result from breeding. These findings were important.
Perhaps 1920 should be used to date the beginning of long-continued systematic breeding, for it was at this time that breeding was started in a greenhouse of the U.S. Department of Agriculture. Schuster, of the Oregon Station, began his work then also. Though not fully continuous in the 1920's, the work at Oregon has been nearly continuous since about 1929. Systematic New York Station work began in 1924 with Slate and has been continuous since.
At present it is generally recognized that continued strawberry breeding is a necessary part of experiment station work. It has been economically valuable both to the United States and to the states where important varieties have resulted. The federal work has resulted in important varieties that have advanced the industry, especially in such better shipping varieties as Blakemore, Dixeland, Massey, and Albritton, and in red stele root-rot resistant varieties such as Temple, Fairland, Siletz, Midway, Surecrop, and Mollala. The Northwest of the Washington Station has become the leading variety in Washington and Oregon; Shasta and Lassen and more recently Fresno, Torrey and Tioga of the California Station are the most important varieties in California; so, also, with the Florida Ninety in Florida, Headliner and Dabreak in Louisiana, Jerseybelle in New Jersey, Albritton in North Carolina; and the list could be extended greatly to include more varieties and states. Though the over-all qualities of the present varieties may be 100 percent better than the varieties they replaced, advances already in sight may again double and redouble the value of varieties of the immediate future. Advances are looked for along the lines of "firmer berries, resistance to red stele root rot in most or all varieties, and higher dessert quality with a retention of high flavor under varied weather conditions, and ability to hold up after reaching the market. Other advances are possible in larger berries, frost-hardy flowers, cold-hardy plants, higher yields, and easier capping to eliminate some of the hazards of production and furnish the consumer a better berry. The only limits are those of breeders' imagination, industry, and support, and the germ plasm available in the varieties and species of the world.
No commercial varieties from other States survive in Alaska where the minimum temperatures reported are -60° F. at Fairbanks and -420° F. at Palmer, with annual rainfalls of 12 and 15 inches, respectively. Differences in winter temperature averages are great: as high as +16° for January at Palmer and -12° at Fairbanks. During the winter, warm spells followed by low temperatures, or deep freezing with low rainfall, kill out ordinary varieties near the coast, while deep freezing with low temperatures, or just very low temperatures kill them in the interior. Experimental work was started in 1901 by C.C. Georgeson with a collection for testing at Sitka of 150 F. chiloensis plants on the Yakutat Beach. In good soil these native plants were extremely vigorous but produced few flowers and no fruit. When reset in a sterile volcanic soil, they bloomed and fruited, with the largest fruit being one inch in diameter. Plants of this species were hardy in the wet coastal climate where temperatures drop to -20° to -25° F. Plants of F. ovalis, from the interior of Alaska where the temperature goes to -65° F., thrived when planted in the interior near Fairbanks, being extremely vigorous but with few flowers or fruit; yet three years after some were planted in the wet, mild coastal climate of Sitka only three weak plants remained. F. ovalis is, in general, very susceptible to leaf spot and mildew.
Crossing was started by Georgeson in 1905, rising a cultivated variety from the States called Hollis, of unknown origin. It was pollinated with the Yakutat chiloensis. In later years he used several other varieties with chiloensis. Seedlings produced no fruit until 1908 and but few until 1909. About 10 percent of this F1, had large berries that were reported to be of delicious flavor. The hybrids had extraordinary vigor, growing even to 18 inches high. F. chiloensis gave the best results as a parent; and the hybrids were reported as perfectly hardy both on the coast and in the interior where the temperatures often went to -50° F. In 1910 hybrids of F. ovalis were made and showed improvement over the wild ovalis. One of the best selections was an F1, of Magoon x ovalis, which produced large, deep red, firm berries of good flavor. Contrastingly, in a letter of September 3, 1923, Georgeson stated that hybrids with chiloensis were soft, very light colored, but unsurpassed in flavor. When the work ended in 1923, over 11,500 seedlings had been raised, and the best selections had been widely distributed under number to be grown commercially. Most of these have been lost but several are being grown commercially still. One called Sitka 275, which may be a seedling resulting from Magoon x ovalis, is still known. In general, near the coast these Sitka hybrids are hardy, vigorous, productive; the fruits are very small to large, very soft, mostly pale colored.
Recent breeding work has been carried on by C.H. Dearborn at Palmer, near the coast, and by A. Kallio at College, near Fairbanks in the interior. Many additional plants of both ovalis and chiloensis have been collected; and ovalis resistant to mildew along with perfect-flowered ovalis and chiloensis have been found.
At Palmer, tests of 74 varieties from other states indicated that none was hardy enough for Alaska, even when mulched. Sitka hybrids, from Georgeson's work, that had survived for thirty years, were collected and observed at Matanuska from 1950-1953. Crosses were first made in 1952 to obtain winter-hardy, red-fruited varieties. Several hundred selfed seedlings of these hybrids were tested; also, about 30,000 seedlings of crosses of Sitka D with varieties from other states, which included Midland, Jerseybelle, Sparkle, Gem, Radiance, and Marshall, were set in the field at Palmer. Fifty-two selections were made by 1955. Sitka D x Midland seedlings appeared to be among the most hardy at Palmer and best flavored. No plants of progenies of 23 crosses of commercial varieties survived when left unmulched. Crossing has been discontinued.
In 1950 Kallio also began collecting plants for the station at College near Fairbanks -- Sitka hybrids resulting from Georgeson's work as well as native ovalis and chiloensis. Some chiloensis came through the winters at College and, although many do not flower and fruit, a few do. Hybridization work was started in 1953. Objectives are hardiness, drought, leaf-spot, and mildew resistance, and firm, good-flavored fruit. By starting seedlings in January in the greenhouse under lights, seedlings large enough for the field are obtained by June and early July, and the first selections can be made the next year. Of 13,088 seedlings set in 1962, 94 percent, or 12,316, survived the very cold winter of 1962-1963, and 769 were selected in 1963 for further study. The summer temperatures are low enough so that many are everbearing.
Strawberry breeding in California presents an interesting case. Intensive breeding work, along with related investigations, is conducted at the California Experiment Stations; more breeding work proceeds at the private grower-supported Strawberry Institute of California and both are closely allied to the strawberry industry of California which in some places produces the heaviest yields per acre in the world. Much of the material about the Strawberry Institute and the strawberry industry of California is outside the avowed subject of this chapter, but because of the almost symbiotic relationship of industry to experimental work, descriptions of both, as well as descriptions of some of their techniques, are considered pertinent.
Strawberry breeding began at the Davis Station in 1925-1926 and has continued to the present. William T. Howes and A.G. Plakidas initiated the first work. Some selections were made of their crosses in 1927 and W.T. Horne made further crosses that year. He was succeeded by Dr. Harold E. Thomas and Earl V. Goldsmith, 1928-1945, Department of Plant Pathology, Berkeley. After they left the University to establish the Strawberry Institute of California in 1945, Dr. Richard E. Baker, Department of Pomology, Davis, was in charge and was assisted by Victor Voth. Baker resigned in 1953 and was replaced by Dr. Royce S. Bringhurst, who has continued the work in collaboration with Victor Voth from 1953 to the present. In 1952 a temporary branch strawberry research station was established at Torrey Pines, near San Diego in southern California with Victor Voth in charge. The southern California headquarters was moved to the South Coast Field Station of the University of California at Santa Ana in 1956, but work has continued on a reduced scale at Torrey Pines to the present.
The first Thomas-Goldsmith seedlings were fruited in 1930 at the San Jose Station near Santa Clara. The first crosses, made in 1929 by Goldsmith, were actually unauthorized, but were the result of his curiosity when he was foreman of the Deciduous Fruit Field Station of the University of California at San Jose. These were followed by systematically building up the desirable characters toward an ideal type which resulted in the release of the Shasta, Lassen, Sierra, Tahoe, and Donner in 1945. Of these, Lassen (originated in 1936) proved to be best in southern California because of its low chilling requirement, relatively high tolerance to salinity, wide adaptation under a variety of planting systems and high productive capacity. The fruit is mediocre to poor in quality, soft, ships poorly, tends to roughness and is unsatisfactory for freezing. Shasta, originated in 1935, proved to be best in coastal central California because of continuous production under the prevailing conditions, where fruit is harvested from the same plants from April through November. The fruit is good in quality, ships well, and is passable for freezing. Sierra, Tahoe, and Donner failed as varieties in California but Donner is a leading variety in Japan. From the Thomas-Goldsmith selections, Campbell and Cupertino were released by Baker in 1949 and both failed. Solana, which originated in 1935, was released by Bringhurst and Voth in 1958 because of its high dessert quality. Solana is established as the dominant variety in the Oxnard district of Ventura County and around Fresno, replacing Lassen in both areas, and is grown to a limited extent in other areas including the central coast near Watsonville. The fruit is not satisfactory for freezing.
Bringhurst and Voth continued the systematic building of ideal types to improve on the qualities of Shasta and Lassen, and to obtain varieties for special conditions. In addition to Solana, they introduced Fresno, Torrey, and Wiltguard (see p. 159) in 1961 and Tioga (see p. 159) in 1964. Fresno, Torrey, and Tioga were all selected in 1955 and all have the same parentage. Their plant habits and adaptation are similar to those for Lassen. Their fruit resembles that of Lassen in color and general shape, but they are larger, more attractive, firmer, better flavored, easier to harvest and all of them cap easier than Lassen. Torrey is darker than Fresno or Tioga. Wiltguard, selected in 1954, is resistant to Verticillium wilt and the fruit is particularly high flavored.
Fresno has rapidly become the dominant variety in southern California, replacing Lassen. Torrey has also become established, but to a more limited extent; since it has an even lower chilling requirement than Lassen it performs best at warm winter sites near the sea. Tioga has the greatest potential of the group because of wide general adaptation (including the Shasta area of the central coast), higher yielding ability, and exceptionally firm fruit. Wiltguard is not succeeding.
The success of the new "University" varieties is largely due to the development of planting systems which favor their best performance. Most noteworthy have been the summer planting of cold-stored plants and the use of clear polyethylene bed covers to raise the winter growing temperatures.
The present program conducted by Bringhurst and Voth involves research facilities in every important environment of the state. Detailed performance testing is carried out at the following locations: Davis, interior valley; San Jose, central coastal valley; Salinas, central semicoastal; Watsonville, central coastal; Santa Ana, south semicoastal; and Torrey Pines, south coastal. Most of the crossing is done in the greenhouse at Davis. From eight to fifteen thousand seedlings are fruited each year; about half are grown at Winters (near Davis) and half at Santa Ana or Torrey Pines. Foundation stocks are maintained at Davis, at Winters, and at the Antelope Valley Field Station of the University of California near Lancaster in Log Angeles County. Virus-free stocks are maintained at the latter site.
Computer technology can play an important role in large scale breeding work. This view is supported by various factors, some of which cannot yet be fully realized in terms of their potentialities. First, the computer can be programmed to reduce into a comprehensible form, at minimum cost, the large quantities of data which breeders amass each year. In the California program, field data are summarized, the standard deviations are calculated for the various fruit traits that are measured, and "performance," a value which is weighed heavily by yield but considers appearance, fruit size, and firmness as well, is calculated. Data can be recorded on cards in the field to reduce the cost of obtaining analyzable data. At the end of the harvest season (four to seven months), the values can be obtained for seasonal summarization by machine.
Meaningful genetical studies also are possible. Using the parent-offspring method, heritability values can be calculated for various traits, and correlations between pairs of traits can be determined. Many genetical problems can be subjected to analysis. As an example, in the California program there is interest in a possible negative relationship between Verticillium wilt resistance and desirable performance traits. It has been noted that, with intensive selection for desirable traits, most of the selected clones are susceptible, even though both parents may be resistant. Genes conditioning wilt resistance may be linked with genes that condition undesirable performance traits. Since the latter are quantitative in nature and the relation among them is probably complex, an appropriate computer program will aid in interpretation. Without the computer, a much less satisfactory evaluation would be possible economically.
It is conceivable, but not presently feasible, to program a computer to scan all possible combinations of heritable characters. However, by weighting some of the important characters according to their occurrence and distribution in the breeding population, effective predictions concerning the outcome of particular breeding programs can be made. This at least would introduce an element of control into breeding projects that has previously been impossible. And, beyond this, realistic estimates of potential progress can thus be made, providing guidelines for further experimentation, saving the waste of much needless investigation.
The Strawberry Institute, a non-profit institution located at Morgan Hill, was organized by E.F. Driscoll in 1944; at that time H.E. Thomas became its director and pathologist, and E.V. Goldsmith, its plant breeder. The Institute was organized to assist the growers belonging to it (Driscoll Strawberry Associates) in solving their disease, insect, variety, and other problems. The Institute has also furnished disease-free stock to their growers. Thomas and Goldsmith continued strawberry breeding along lines they started at the University, rising the same breeding stock-growing seedlings (up to 45,000 in some years) and testing selections. At first the varieties grown by Institute members were Shasta, Lassen, and other standard varieties; now they are mostly varieties originated by the Institute-including Goldsmith (Z5A), a patented variety, and D4, and 5, true everbearers. In 1959 a profit corporation, "Strawberry Institute Nursery," also with H.E. Thomas in charge, was organized to separate the plant propagating work from the strictly service work. Plants are furnished to the Institute members at cost, but sold to non-members at the market price. In 1962 Institute members had about 1,600 acres in production. The Goldsmith variety occupies almost two-thirds of the acreage, and performs best in central coastal sites near the sea. It is unsatisfactory in southern California. Goldsmith is liked for its heavy mid-summer production (later than Shasta), large size, high gloss, and remarkable carrying quality. It is weak in spring production, unsatisfactory for freezing, and is subject to 11 transient yellows." D4 is important in the Oxnard area where it competes with Solana. The everbearers yield well, but do not hold large size as well; one has high flavor.
The development of the California strawberry industry began about 1910 after the Marshall, then called Banner, had been introduced into the Watsonville area near the coast south of San Francisco. Later it was grown in the Sacramento area as the Oregon Plum and in the Fresno area as Marshall. It was the leading variety for thirty years until after the introduction of the Shasta and Lassen in 1945. Nich Ohmer was also grown during the latter part of this period as a shipping variety. In 1918 the Central California Berry Growers' Association was organized and from 1920 to 1947 E.H. Haack was its manager. E.F. Driscoll and Ed Reiter were especially helpful in testing the early selections of the California Station.
In the 1940's before World War II, the California acreage was about 5,000. Marshall (Banner) and Nich Ohmer were the chief varieties in central and northern California and Klondike in southern California. With the removal of the Japanese from the Pacific Coast, during the World War II period, the strawberry industry dwindled to less than 1,000 acres. Yields were low in the prewar years because of the lack of suitable adapted varieties; most planting stock was infected with virus and the Marshall (Banner) variety was particularly sensitive to the prevalent viruses.
A sound basis for expanding commercial production in California was established in 1945 with the release of five varieties by the University of California for commercial use; these were soon reduced to Shasta and Lassen. The new varieties were tolerant of the prevailing viruses and relatively free of virus infection. Their pattern of production in the central coastal area was much more desirable than that of Marshall (Banner). About 40 percent of the fruit is produced in the July to November period on second-year production and no runners are produced by Shasta plants after the first year. The acreage expanded rapidly during the postwar years following the release of the "University" varieties and the return of the Japanese farmers. Improved culture and the expanding market also stimulated the increase in production. By 1956, twenty-two thousand acres were in production and yields of twenty to twenty-five tons per acre were obtained by the best growers, with returns of as much as $10,000 to $12,000 per acre. In 1956, California produced 55 percent of the nation's crop on about 12 percent of the acreage with a value of nearly $45,000,000; this from a total investment by the California Experiment Station of only $72,000 over a fifteen-year period for the five varieties introduced in 1945. Production in California now constitutes about 40 percent of the national total, produced on less than 10 percent of the acreage with a value up to $45,000,000 annually. Southern California produces the early crop and finishes about July 15, when harvest is stopped to prepare the soil for the new plantings. Central California starts in April and continues to November or December.
The greatest concentration of the industry is around Monterey Bay in central California, where about half the total crop is raised. This is due to the effect of the interaction among (1) the relatively low extent of winter chilling, (2) the cool summer growing conditions, and (3) the day length on flower bud formation of certain varieties. Strawberries have a response to chilling or lack of chilling similar to deciduous fruit trees. Under the cool coastal California growing conditions lack of sufficient winter chilling is expressed in the production of flower buds and fruit on many ordinary non-everbearing varieties throughout the longer days of summer. Although the Marshall (Banner) produced some fruit throughout the summer, the Nich Ohmer produced more consistently after July 1 and it is the Nich Ohmer type of response in Shasta, Lassen, and other varieties that has made them so valuable. These varieties have not proved so tolerant to virus as at first supposed, and planting of virus-free stocks has become important in recent years.
Nearly all fields are fumigated with mixtures of chloropicrin and methyl bromide under polyethylene film before planting, at a cost of up to $400.00 per acre. The fumigation essentially solves the replant problem since new plantings on properly fumigated soil respond about like plantings on good soil never planted to strawberries; the cost is more than offset by the increased yields. Good soils that would be unsatisfactory without fumigation because of previous crop history (tomatoes, etc.), or disease problems (Verticillium wilt, etc.), can be used. In nearly all cases, the plants grow better after fumigation.
In the Los Angeles-Orange Counties where Lassen has been the important variety, annual planting is universal, and fruit is harvested for only one year -- rather for only three to four months out of that year. Plant density ranges from about 24,000 per acre on summer plantings to over 30,000 on some winter plantings. Clear polyethylene bed-covers, machine-laid, shortly after the plants are set, on all winter plantings and about January on summer plantings, are used on almost all plantings. For summer plantings, plants are cold-stored at 28 to 30 F. from the time they are dug in December and January until planted in August. Yields from summer plantings are extremely high, and the fruit quality is good. Winter plantings yield much less but the fruit quality is often better than from summer plantings. In southern California, where only high-valued land is available, growers plant strawberries every year on the same land, fumigating between the plantings. It is convenient to rotate winter plantings with summer plantings in this regard, since there is time to prepare the soil for a summer planting after harvest has been terminated on the previous year's winter planting, but not time to prepare the soil for summer planting after the harvest has been terminated on the previous year's summer planting. It is for this reason primarily that almost half the southern California acreage continues to be winter plantings despite the lower yields and income.
It has been said that the yields in California have declined since the peak year of 1953, and that much of the decline was due to increasing virus problems. Actually, record production of about a ten-ton per acre average for the state was realized in 1962, and that record was broken in 1963 with an average of over twelve tons per acre. Costs in California are $2,000 to $4,000 per acre but returns may be twice or three times that.
The so-called "virus reduction" of yields during the 1950's was at least in part due to a successive series of warm winters, which were particularly damaging to the Shasta variety. The record yields of 1962 and 1963 are due to a combination of cultural factors including: the use of clean planting stock, soil fumigation, control of the cyclamen mite, the use of polyethylene mulch in connection with annual planting in southern California, the adoption of the summer planting system of culture, the use of high elevation plants and the proper timing of winter plantings. In addition, the winters were relatively cold in the central coast area and plants of the Shasta variety received sufficient chilling to invigorate the older plantings.
Virus is a serious problem in the strawberries of California as was recognized nearly forty years ago. Practices to keep nursery stock clean have been used for over thirty years. Isolation of seedlings in breeding has long been used and most nursery stock is propagated in northern California, two hundred miles from the fruiting areas. An extensive indexing and control program is in effect by the State Nursery Service regulatory Department. Freedom from virus of planting stocks is considered the most important means of keeping high production.
Thomas feels that although varieties have been produced that are being used successfully, until perfection is reached, breeders will continue to improve California varieties, for the grower will not cease to want better varieties than he has.
Southern California needs an early high-producing variety with large showy berries that will start in late February or early March and continue to the end of June. At that time most plantings are plowed under, the soil fumigated, and the fields reset in August. The Fresno, Tioga, and Torrey varieties look very promising.
In central California a high-producing sort is needed that starts in mid-April, peaks in May, and continues through June. Then production ceases in the hot interior valley, but along the coast, with its cool climate, production can continue through the summer and fall. The fruit is used for both fresh market and processing, but the fresh market price averages much higher so the best fruit is shipped fresh. The Solana, Lassen, Fresno and Torrey varieties are grown in the hot interior valleys. The Shasta and the Goldsmith varieties are grown along the coast of central California and they produce heavily until late fall frosts and cool weather stop fruit ripening.
In the Central Coast, plantings have been harvested for three or even four years. The cost of harvest increases with the age of the planting, and in general the quality of the fruit decreases. Experimentation by growers following University recommendations, has demonstrated that the profitable life of a planting often does not exceed two harvest years. Summer planting has increased greatly in popularity because of the high first-year production of quality fruit. As new varieties such as Tioga are used with this system, considerable change can be anticipated in the next decade.
The outstanding characteristics of the California varieties are their large average size and their periods of production ---the Southern California fields producing the highest yields in the world and over a period of about four months, the Central California fields nearly as large yields but extended over a period of over six to seven months, with about 40 percent of the crop coming after July 1.
Breeding work with strawberries becomes difficult when attempted in the subtropical climate of Florida, which lies outside the range of native strawberries. It is very difficult to keep seedlings alive over the long, hot Florida summer with its flooding rains, and it is even more difficult to evaluate the seedlings. However, if it becomes possible to raise planting stock of Florida Ninety, or of seedlings of southern parentage, in Florida with or without cold storage, the improvement of varieties may be rapid, and in Louisiana and southern Japan as well.
Dr. A.N. Brooks, plant pathologist at Plant City, has been in charge since the breeding work started. Many selections and varieties of other breeders were tested in the early years, and seedlings were raised at times. All the earlier breeding work, however, was drowned out by floods in the 1930's. In 1948, one lot of 1,075 open-pollinated seedlings of Missionary was grown from which 120 were saved for further testing. From these, the Florida Ninety was finally selected and introduced in 1952. In 1954, Dr. Scott, of the U.S. Department of Agriculture at Beltsville, Md., made crosses of Missionary x Florida Ninety and x Albritton and of Albritton x Florida Ninety, and 1,937 of their seedlings, plus seedlings from open-pollinated Florida Ninety and Florida 45, were grown by Brooks at Plant City. In 1955, 1956, and 1957 additional seedlings were raised; these from over 35,000 seeds of crosses, with each other and with other varieties, of Missionary, Florida 45, and Florida Ninety. In 1964 a new strawberry and vegetable field laboratory was opened for research with about twenty acres of land and new laboratory buildings at Dover, just east of Tampa.
Florida Ninety originated from open-pollinated seed of Missionary from the Experiment Station planting containing over 60 other varieties in 1948. It is undoubtedly a cross of Missionary with some other variety (probably Klonmore) because selfed Missionary seedlings are generally weak and their yield and fruit size far too small to be commercially useful.
According to Fletcher (p. 70), commercial strawberry production began in Florida about 1878 and the berries were shipped in open crates by rail, taking about three days to Philadelphia, New York, and Boston. The Wilson was firm enough to stand the trip. By 1888, 20,000 bushels were shipped and in 1889 the first refrigerator car of berries was sent north. Most of the berries were raised in the north-central area near Starke and Lawtey. After 1896 berries were raised near Plant City also, and, beginning about 1960, in southeastern Florida. In 1961, 62 percent of the acreage was in the southeastern area, 27 percent in west-central Florida, and 11 percent in Bradford County of North Florida. By 1933, at the greatest expansion of the industry in Florida, about 2,043 carloads were shipped from about eleven thousand acres. In recent years the shipments by months have been December 2 percent, January 13 percent, February 26 percent, March 43 percent, April 16 percent, May about 1/2 percent.
The recent expansion in strawberry production has been due to far higher yields from the Florida Ninety (selected in 1948 and by 1960 almost the only variety grown) when grown under black plastic mulch and in soil previously fumigated to kill nematodes. Two years after its release in 1952, it composed 65 percent of the acreage of the Plant City area and now is about 95 percent of the total Florida acreage. It is also grown extensively in Mexico.
Florida Ninety took over the acreage quickly because of its vigorous high-yielding plants, its very large fruit size (small size in Maryland), its bright scarlet color and its high flavor, at times with a delightful aroma even after shipment to northern markets. Its yields may be as much as three times those of the Missionary variety it replaced.
|Yields per acre|
Plants are obtained from northern nurseries and are set during January or February in central Florida, or March or April in. north Florida. Then runner plants from this planting are set in a new runner bed in May to June. Plants from this May-to-June plantings are used to set fruiting beds in September and October. To obtain freedom from nematodes, it is important to use only plants grown in fumigated soil, planting them in fumigated soil to keep them free. Black plastic is put on when plants are set; before planting if it is done by hand, or after setting if done by machine. If planting is done by machine, the plastic is slit and the tops pulled through at once to prevent sun burning of plants. Use of plastic ensures that beds aren't washed down with heavy rains, that there is less leaching of fertilizer, and more moisture is available. More vigorous growth with earlier ripening, higher yields, and cleaner fruit follows the use of plastic. About 10 percent of the crop has been shipped by air freight in recent years.
In 1962, J.W. Strobel, at the South Florida Homestead Station, began breeding especially for resistance to Verticillium wilt which had become a major problem in south Florida, especially when the susceptible Florida Ninety was grown as a winter crop on the fields formerly used for tomatoes.
Beginning in 1935, notable work in breeding was done in Urbana by A.S. Colby, who proved that resistance to red stele root rot was inherited. His work culminated in the introduction of Vermilion in 1950. It was a Redstar x Pathfinder cross, late ripening, medium sized, soft, very good in flavor, vigorous, and productive. The plants, however, have become variegated and it is not widely grown. Plentiful, of the same parentage and also resistant to red stele disease, was introduced in 1953, but is little grown.
In 1958 Prof. Zych began strawberry breeding for varieties adapted to Illinois, but especially for high-flavored sorts. Crosses include high x low acid varieties and high x high soluble solids varieties. From 1,000 to 6,000 seedlings are raised each year.
U.S.D.A.-Illinois cooperative breeding work was begun in 1958 at the University of Southern Illinois with Roland Blake, of the U.S. Department of Agriculture, in charge and J.W. Hull assisting. The work at Carbondale is planned to complement that of the U.S. Department of Agriculture at its Beltsville, Maryland, Willard, North Carolina, Cheyenne, Wyoming, and Corvallis, Oregon stations as well as that of the Urbana Station. (See under U.S.D.A., pp. 214-215.)
In 1894 Budd and Hansen crossed two wild strawberries from Manitoba, one perfect, the other pistillate, with five cultivated sorts and grew over 1,000 seedlings. They hoped to obtain the hardiness, remarkable fragrance, and high color of the wild. Three years later they reported that they obtained the hardiness but not the size needed in the F1. Hansen continued this work in North Dakota. In 1903 Irvins reported using Buback, Bederwood, Haverland, and others in breeding. In 1937 T. J. Maney began breeding strawberries and had eight selections at the time of his death in 1945. Though all eight selections were used in crosses of E.L. Denisen, who began work in 1949, they had virus and were discarded. Two of Maney's selections, Iowa-1-3713 (Rockhill S1) and Iowa-68-3702 (Beaver x Dorsett), were the parents of Cyclone, an easy capping home garden variety introduced by Denisen in 1959. Denisen's objectives at first were improved everbearing varieties, as well as runnerless varieties, to be grown from seed that could all be harvested at one time by machine and that would be easy capping. Limited inbreeding was begun later. Other later objectives include easy capping, freezing and dessert quality, market and shipping qualities, larger size, resistance to disease, and irradiation to obtain mutants. Up to 6,000 seedlings are raised annually. Some ovalis, "glauca," and chiloensis selections are being used in crosses. A study of berry flesh and seed colors is under way by R.L. Macha. A study of inheritance of short nodes is also in progress.
In 1935 Dr. Miller and Mr. Hawthorne began strawberry breeding and their first selections were made in Baton Rouge in 1936. Their main objectives were varieties resistant to leaf spot and leaf scorch, with as good shipping qualities as Klondike and less acidity. Major varieties have been introduced as a result of this work -- Klonmore in 1940, Headliner in 1957, and Dabreak in 1961. The Klonmore replaced most of Klondike acreage in Louisiana and in turn was quite rapidly replaced by Headliner, when it was introduced. By 1963, Dabreak constituted about half the acreage.
The objectives of the breeding work have been obtained quickly by raising large numbers of seedlings and repeatedly spraying the young seedlings with spore suspensions of leaf spot so that susceptible ones could be discarded and only resistant ones fruited. Spraying with spore suspensions of leaf scorch was added and recently angular-leaf-spot resistance was added to the program. The seedling numbers were further reduced by discarding all seedlings that did not produce a good stand of runner plants and at times not over 5 to 10 percent were saved for a fruiting test at Hammond. Thus, Klonmore was produced from the cross Blakemore x Klondike by first discarding seedlings in the seed bed that showed leaf spot susceptibility, and by discarding those that produced few runners under their relatively short, hot summer days. Klonmore is highly resistant to leaf spot but susceptible to leaf scorch. It is less acid than Klondike and is more attractive.
Headliner replaced Klonmore and others because it was 30 to 50 percent larger than the older varieties and was superior to them for processing. In tests it averaged 91 percent greater yield than Klonmore over a four-year period. It is not so resistant to leaf spot as Klonmore, and many plants had variegated foliage. Headliner's ancestry is:
Dabreak, introduced in 1961, has replaced Headliner in part, for it is still more productive (42 percent more over a four-year period in one test) in southern Louisiana; and the berry is more attractive and superior in shipping and preserving qualities. Its ancestry is:
Other varieties introduced by the Louisiana Experiment Station are Konvoy, which is soft but rich red, for processing, and Marion Bell (a one-generation inbred of Fairmore); seedlings of both lack vigor and fruit size. Size, flavor, and disease resistance in good shipping varieties continue to be objectives in the Louisiana work. Each year about 14,000 to 15,000 seedlings are raised, but relatively few are fruited. Some years 3,000 to 3,500 are placed in the nursery and 2,500 to 3,000 fruited.
Presently I.C. Haut is leader and F. Lawrence* in direct charge of breeding work at College Park. Since 1938 cooperative breeding with the U.S. Department of Agriculture has been carried on; crosses are made by the U.S. Department of Agriculture at Beltsville, Maryland, and most seedlings grown in red stele-infested soil in greenhouse benches at Beltsville. Susceptible seedlings are discarded and the resistant ones grown to fruiting at the Maryland University Farm at Salisbury, Maryland. Usually 3,000 to 4,000 resistant seedlings are fruited annually and selections for further testing made at the first fruiting. At times seedlings have been grown, and tests for strains of the red stele organism made in the University of Maryland greenhouses.
The University of Maryland, beginning in 1952, has had a separate breeding program. At first the objectives were varieties adapted for high elevations in western Maryland and everbearing varieties. More recently the objective has been directed toward obtaining late-ripening varieties, 2,500 to 3,500 seedlings being raised annually. No varieties have been introduced. Some 30 to 40 selections are under test.
* Transferred to U.S.D.A. at Corvallis, Oregon, September, 1965.
The breeding work, begun in 1950, is carried on jointly by J.E. Moulton at East Lansing and Stanley Johnston at South Haven. The crosses are made and the young seedlings grown in the greenhouse at East Lansing. The seedlings are now fruited at South Haven with both Moulton and Johnston evaluating the seedlings and selections. Objectives are varieties for early, mid-, and late season suitable for both freezing and fresh market, with large, glossy, bright red, firm, tough skinned, and red-to-the-center berries. No varieties have been introduced yet, though selections are under test by growers.
From 1950 to 1953, 132 crosses using 27 varieties and eight selections were made, 19,398 seedlings fruited, and 361 selections made. Howard 17 (Premier) was an outstanding parent in 20 combinations, and the seedlings were notable for resistance to mildew and leaf spot diseases. Fairland x Tennessee Shipper was notable for being productive and for giving firm, smooth, bright red, red-to-the-center fruit. Tennessee Shipper was an unusually good parent in eight of the nine crosses tested. Redcrop, Midland, Sparkle, and Marshall also gave high percentages of good seedlings (1955).
Some modifications of breeding technique were described by these workers (1955). The plants for crossing are dug just before severe weather (late October or early November), brindled and stored in sphagnum at 32° F. until early December. They are then potted and held at 54° F. for two weeks to establish roots, then the temperature is raised to 70° F. Supplementary light is used through February from four P.M. to midnight to give a sixteen-hour day to lengthen the peduncles and to develop more pollen. As pollen is not shed until after the flowers open, the flowers are emasculated and pollinated at the same time. Berries in the white stage have mature seed and are harvested. When sowed as soon as harvested, seedlings begin to appear in about two weeks. When large enough to handle, they are flatted, 80 to a flat, and in ten to fourteen days are ready for the field -- late May to early June. Four to five runner plants per seedling are allowed to root and later ones removed.
Hybridization was begun at Excelsior in 1908 and has continued up to recently. Charles Haralson did the early breeding and was followed by A.N. Wilcox. W.D. Valleau, 1914-1925, also worked in the breeding program, particularly on the inheritance of sex types. In the early work, varieties were intercrossed to originate hardier varieties and 5,000 to 10,000 seedlings were raised between 1909 and 1924. This kind of breeding was continued on a limited scale still later. Selection within self-fertilized lines was begun in 1922 and continued until Wilcox's death in 1963. The principal varieties used in selling were Belt, Chaska, Dunlap, Minnehaha, and Howard 17 (Premier); others used were Beaver, Campbell, Duluth, Early Bird, Mastodon, and Minnesota. Although there was reduction in vigor in the first generation, the later generations averaged more vigorous than the first selfed generation. The more vigorous S1 were selected for further selling. Inbreds were selected for firmness, productivity, winter survival, and resistance to disease. Besides research on inbreeding, a study of value of selections of the F. virginiana for breeding was one part of the program. In the early 1920's M.J. Dorsey was associated with the breeding work and helped in the selection of Duluth (everbearing) (Pan American x Dunlap), Minnesota (Dunlap x Pocomoke), Minnehaha, Chaska, Easypicker (Crescent x Dunlap), Nokomis, and Deephaven. At various times, W.H. Alderman, J.H. Beaumont, E. Angelo, W.G. Brierly, and F.E. Haralson assisted in the work. In the later work, though inbreeding was emphasized, Evermore (1945) (Duluth x Dunlap), Arrowhead (1946) (Duluth x Dunlap), and Burgundy (1944) (Easypicker x Dunlap), varieties from outcrossing, were introduced. Dunlap was notable in transmitting phenotypic characters, especially hardiness, vigor, and runner production. It seemed also to transmit more earliness to its seedlings than most parents. On the whole, Dunlap was less productive of good inbreds than several others.
Some research publications on the strawberry are discussed below.
"Sterility in the strawberry," by W.D. Valleau (1918), is an intensive study of the morphology of sex types of the strawberry. Valleau noted that the flower parts were in multiples of five except for the pistil; that the native parental species were dioecious; that staminate (male) plants have pistils that are only rarely functional; that pistillate plants have undeveloped stamens that rarely develop pollen; that there is a correlation between flower position and pistil fertility, fertility decreasing in the later flowers to open on an inflorescence; that sterility of the later flowers is more general in hermaphrodites than in pistillates, suggesting that hermaphrodites have been derived from staminates; that the percentage of aborted pollen is not constant in the anthers of a single flower, nor in the flowers of any variety; that there is no evidence of physiological self-sterility in the strawberry, and that nubbins are due to pistil sterility.
"How the strawberry sets its fruit," by Valleau (1918), shows the arrangement of the flowers and berries on a cluster. The first flower to open, the primary," is the largest and develops into the largest and earliest berry to ripen. The second two, the "secondary," are next largest flowers and fruits and ripen next, the next four are the "tertiary" and have still smaller flowers and fruit.
"The inheritance of flower types and fertility in the strawberry," by Valleau (1923), indicated that hermaphrodites do not carry the factor for femaleness, but that pistillate do carry hermaphroditeness as a recessive, so that a one to one ratio results when pistillates are crossed with hermaphrodites.
In "Breeding behavior of the strawberry with respect to time of blooming, time of ripening, and rate of fruit development," by R.M. Peterson (1953), nine inbreds of varieties were selfed and intercrossed to determine whether studies of the progenies would furnish evidence of genetic differences. All three characters were quantitatively inherited with no heterosis. Between varieties there were significant differences in each character, the most important being in rate of development from time of pollination to ripe fruit. The difference here was as great as 8.8 days.
In "The breeding value of selected inbred clones of strawberries with respect to their vitamin C content," by T.H. Anstey and A.N. Wilcox (1950), selfed and crossed seedlings from five original varieties were tested: Marshall (inbred three generations), Dunlap (inbred three generations), Minnehaha (inbred two generations), Chaska (inbred one generation), and Howard 17 (Premier) (inbred one generation). High vitamin C was partially dominant to low vitamin C. Some selfed and some crossed seedlings had higher vitamin C content than the parents, indicating a recombination of favorable genes within a parent or from both parents, with vitamin C content as high as 165 milligrams per 100 grams in some seedlings of crosses involving each parent.
E. Angelo and associates, in "Studies on some factors relating to hardiness in the strawberry" (1939), tested varieties for hardiness to cold and Gibson was considered hardiest, hardier than Dunlap.
In 1948 Jean P. Overcash started a breeding program at State College to obtain varieties capable of withstanding the hot, dry summers. Some seedlings, 500 to 3,000, have been grown nearly every year since. About 30 selections are in replicated tests in one or more locations and about 60 more selections are in single-row plots.
Early breeding at the Columbia station was begun by J.W. Clark in 1890 and reported by Charles A. Keffer in 1893. Open-pollinated seedlings of Gandy, Bubach, Crescent, Lady Rusk, and Warfield were fruited in 1892. Of 4,300 seedlings, 245 were saved for later testing. No varieties resulted from this early work but information on inheritance of sex did. Seedlings of four pistillate varieties gave 1,714 perfect (41 percent) and 2,420 pistillate (59 percent) seedlings, somewhat more pistillate seedlings than the one to one ratio usually obtained.
Later breeding was begun in 1934 by H.S. Swartwout. About 10,000 seedlings were fruited up to 1946, about 40 selections were made, and one variety -- the Armore, large-fruited, very productive, high flavored but mildew susceptible -- was introduced in 1950. Swartwout's objectives were (1) a variety with good yielding, dessert, and shipping qualities to replace Aroma in the Ozark region; (2) a local market variety to replace Dunlap and Howard 17 (Premier) in north Missouri; and (3) a superior processing variety. Parents used in his work were Howard 17 (Premier), Aroma, Blakemore, Progressive, Dunlap, and Klondike.
In 1953 D.D. Hemphill took over the breeding work. About 40,000 seedlings have been fruited, 262 selections made, of which 29 are being evaluated in replicated tests for comparison with standard varieties. No varieties yet have been named from this work. Hemphill's objectives have been (1) a good-flavored, home garden variety resistant to red stele and leaf diseases; (2) for south Missouri, a commercial variety to replace Blakemore, resistant to red stele and leaf diseases with good shipping and processing qualities; and (3) a local market variety for north Missouri resistant to red stele and leaf diseases with excellent flavor, size, and appearance.
Strawberry breeding in Durham began about 1940. L.P. Latimer was in charge until 1949, when E.M. Meader took over the work. E.G. Corbett (1962) assisted from 1959 to 1962. The primary objective was late varieties. Merrimack, Blaze, Strafford, Jamboree, Phelps, and Great Bay were named. None is of more than local importance. Beginning in 1955 another objective has been to obtain runnerless, seed-propagated varieties, because loss due to virus might be avoided if all plants were grown from seed. All runnerless material to date has been everbearing. By the use of a 17-hour photoperiod most potential runner-making seedlings can be eliminated. In each generation of breeding with this objective there have been fewer runner-making plants. One combination of runnerless parents gave 95 percent runnerless seedlings; and one inbred progeny gave only 1 percent with runners. About 10,000 seedlings have been grown so far. A naturally occurring twelve-ploid seedling was obtained among the selfed seedlings of NH-2 [Lee Gem x Macedonian (seed from Greece)] x Sans Rivale, a line being bred for non-runnering. It was not fully fertile.
Since the initiation of breeding work, eight varieties have been introduced by the Experiment Station at New Brunswick: Pathfinder, Redwing, Julymorn, Crimson Glow, Sparkle, Redcrop, Jerseybelle, and Vesper. The first crosses were made in 1928 by J.H. Clarke, using as parents Howard 17 (Premier), Aberdeen, Lupton, Mastodon, Chesapeake, Gandy, Wyona, and Pearl, the last three for their lateness; and 1,800 seedlings were grown and tested. Additional crosses were made in the following years, using other varieties, as well as selections of the earlier seedlings, as parents. By 1937, over 22,000 seedlings had been set. In 1939, 138 were still being tested and 70 were discarded. Gandy, Chesapeake, and Lupton were disappointing as parents; and Howard 17 (Premier), Aberdeen, Pearl, and Fairfax were considered good parents. Lupton, used as a parent for its excellent shipping quality, transmitted its poor dessert quality but not its good shipping quality. Though five varieties were named by Clarke, only two became commercially important -- Pathfinder (Howard 17 x Aberdeen), named in 1937, and Sparkle (Fairfax x Aberdeen), named in 1942. Sparkle is still an important variety in all northeastern United States. A sixth variety, Redcrop, was named and introduced in 1949 but did not succeed, probably being weakened by virus.
Following J.H. Clarke, F.A. Gilbert was in charge from 1946 to 1950. The cross made by him in 1946 (or 1947) from which Jerseybelle originated was NJ-953 [(Lupton x Aberdeen) x Fairfax] x NJ-925 (Pathfinder x Fairfax). It was selected in 1948 and introduced in 1955 because of its attractive color, high gloss, and large size. It quickly became the leading variety in New Jersey and in 1963 constituted 60 percent of the acreage there; Dixieland, Pocahontas, Surecrop, Earlidawn, and Sparkle comprising most of the rest. The importance of virus-free stock of Jerseybelle is illustrated by the contrast in yields of 5,130 quarts per acre in 1959 and 14,338 quarts per acre in 1961 after virus-free stocks were available for test plantings.
Since 1950, L.F. Hough has been in general charge but several, including J.N. Moore and H.H. Bowen, have been in direct charge, making the crosses and selections. Beginning in 1955, larger numbers of seedlings have been grown. In 1957 about 20,000 were fruited, from which Vesper was selected. Vesper (Utah Shipper x Jerseybelle, introduced in 1962) is still larger and later than Jerseybelle and also has great beauty. Though both Jerseybelle and Vesper have the deep color of Fairfax with a superior gloss, neither has its high flavor nor its resistance to leaf spot, leaf scorch, and Verticillium wilt, to which both are very susceptible. Jerseybelle is moderately productive, while Vesper is highly productive where leaf diseases are not too severe.
Two soil-borne fungus diseases, Verticillium wilt and red stele, are serious in New Jersey. Since 1958, E.H. Varney, plant pathologist, has cooperated in the breeding program for resistance to these diseases; and in this work there has been close cooperation with the staff of the strawberry breeding project of the U.S. Department of Agriculture, at Beltsville, Maryland. Catskill, Surecrop, and Vermilion were found resistant to Verticillium wilt and were used in crosses; the seedlings screened for resistance in a heavily infested field. Similar breeding and screening for resistance to red stele is being carried on.
At the present time the general objectives are (1) superior fresh market varieties, (2) processing varieties easily capped, (3) earlier and later varieties, (4) home garden everbearing varieties. Other objectives include frost hardiness of flowers, very large berries, true breeding lines for F1 hybrid seed-propagated varieties, and runnerless seed-propagated varieties.
In 1963 there were about 600 selections (32 for advanced testing) and 25,000 seedlings in the field for fruiting in 1964, with H.H. Bowen in direct charge.
In "Inheritance of the so-called everbearing tendency in the strawberry," J.H. Clarke (1938) reported that in most crosses everbearing behaved as a dominant character. No homozygous everbearers were found. One produced no everbearing seedlings. In one, everbearing was recessive and in one the percentage of everbearers was lower than in most.
Crosses were first made at Geneva in 1889, before any other experiment station in the United States. Other crosses were made in 1892, 1893, 1898, in 1906, 1907, 1910, 1911, 1913-1915, 1920, 1924, 1926, 1928, and nearly every year since. Up to 1917 R.D. Anthony reported that nearly 2,000 had been selected for a second test, but only 12 had been named. None became widely known. Slate began his extensive breeding in 1923. Since 1950 he has been assisted by J.P. Watson and since 1960 by D.K. Ourecky also.
The most widely known variety, Catskill [Marshall x Howard 17 (Premier)], introduced in 1933, has steadily gained in importance because of its large, attractive berries and great productiveness. It has been the standard mid-season variety from the Pennsylvania-Maryland line northward for over twenty-five years. Other varieties are Clermont, Empire, and Eden, grown to a slight extent; the new Fletcher (Midland x Suwannee), late mid-season, introduced in 1959 for its high flavor and good freezing quality; Frontenac [Erie x (Fairfax x Dresden)], late, introduced in 1959 for its large, firm, attractive berries that freeze well and for its productive plants; Fulton (Starbright x Pathfinder), mid-season, introduced in 1959 for its firm berries; Fortune [U.S.D.A.-2827 (Dorsett x US-367) selfed], early mid-season, named in 1961 for its attractive, high-flavored berries of only fair freezing quality; Geneva (N.Y.-316 (Streamliner x Fairfax) x Red Rich (Rockhill x Fairfax)), late mid-season and everbearing, introduced in 1961 for its excellent-flavored, large, attractive berries. This last variety makes runners freely at Geneva but few plants, except under high culture, farther south.
In "The best parents in strawberry breeding," Slate (1931) summarized his breeding work: the crossing of 28 varieties to produce over 13,000 seedlings from 1924-1931. He called attention to Howard 17 (Premier) as an outstanding parent, transmitting smooth regular-shaped berries to its seedlings. In 1943 he reported on the years 1936-1942, in which he raised 11,761 seedlings and selected 292 for further testing. Again Howard 17 (Premier) was reported as an outstanding parent, but Fairfax and Sparkle were also considered notable.
In "Inheritance of Sex in Strawberries," R.D. Anthony (1917) reported on the inheritance of sex in strawberries. For 48 crosses of imperfect (pistillate) x perfect, 1,591 perfect to 1,621 imperfect were obtained, close to the 1 to 1 ratio, and from 23 crosses of perfect x perfect 2,190 perfect, 9 semiperfect (having some functional pollen), and 5 imperfect seedlings were obtained. But from 22 perfects selfed, there were 3,159 perfects, 685 semi-perfects, and 474 imperfects.
Although W.F. Massey began testing seedlings as early as 1893, continuous strawberry breeding began at Willard (Plate 15-1) in 1928, when the U.S. Department of Agriculture in cooperation with the North Carolina Department of Agriculture, with Charles Dearing in charge for North Carolina, began planting seedlings which had been raised in Maryland. In 1936, the work was made cooperative with the North Carolina Experiment Station with E.B. Morrow in charge for North Carolina. Thereafter, seedlings were raised at both Raleigh, North Carolina, and Glenn Dale, Maryland. The Blakemore, sent to Willard in the spring of 1927 as a selection, was introduced from Willard in 1930. The Fairmore, Daybreak, and Eleanor Roosevelt were introduced in 1939, the Massey in 1940, and the Albritton in 1951. The Fairmore and Daybreak were soon discarded, having been weakened by virus diseases, while the Eleanor Roosevelt, although very large and firm and producing large berries only, was too dark and dull. The Blakemore, Massey, and Albritton succeeded, the Blakemore because of its superior shipping quality and bright color, and the Massey and Albritton because of their large size, high flavor, and good shipping quality. The Albritton is one of the most beautiful of berries with a high gloss over a scarlet surface. This variety, by Morrow and Darrow, is notable because it resulted from limited inbreeding, raising selfed progencies of Southland and Massey, crossing the best of these seedlings, No. 1065 x No. 1053, and selecting the best from the resulting population. After its introduction, Albritton quickly replaced Massey, since it had a tougher, glossier skin, equally high flavor and was more productive. Although the Albritton has succeeded remarkably in North Carolina, where it is an almost ideal variety, it is far less hardy than other varieties grown farther north.
The objectives of the work have been large, attractive, good shipping, disease resistant, high-flavored, productive varieties for the Southeast.
After Morrow's death in 1956, Schneider was in charge from 1956 to 1958, and was followed by Correll in 1959, and by G.J. Galletta from 1959 to the present.
Among the results of several notable breeding projects are these publications:
In 1941 Morrow and Darrow reported on "Inheritance of some characteristics in strawberry varieties" that seemed important in the breeding work in North Carolina. During mild periods in the winter in eastern North Carolina flower clusters of Blakemore and Missionary develop to the flowering stage and these flowers are killed by later freezes. As the early flowers develop into the largest berries, it seemed that studies might indicate a better genetic control of this character. Selfed seedlings of 7 varieties and various crosses of Blakemore, Daybreak, and Fairfax were observed. The complete flower history of any selfed line or cross showed that plants with the most flowers killed generally produced later the most flowers in both early and crown crop. Thus, conditions favorable for early flowering were favorable for further extensive flower bud formation and earliness of selfed seedlings gave a correct index of genetic earliness. Fruit characteristics of 100 seedlings (Plates 13-3a and 13-3b), usually of 9 selfed and 11 crossed lines -- shape, color, seed color, seed placement, firmness, separation of calyx, size of calyx, hollowness, flesh color, and size -- were all studied and the best sources of the most desirable characters determined.
"Effects of limited inbreeding in strawberries" (1952), by E.B. Morrow and G.M. Darrow, indicated that selfed, backcrossed, and sib-crossed progenies resulting from inbreeding usually have greatly decreased vigor when compared with the parent varieties. However, seedlings with the highest rating for vigor could be selected in all progenies (Plate 14-1). It seemed possible to utilize the superior qualities of Howard 17 (Premier) and Blakemore, even though they and many of their seedlings mutate to variegated plants. None of eight inbred selections tested for yield approached the parents. The value of inbreeding seemed to be (1) the evaluation of a variety for its breeding value and (2) in concentrating desirable characters in the inbreds.
"Genetic variances in strawberries" (1958), by Morrow, Comstock, and Kelleher, indicated that the "seedling square" method of testing seedlings is an entirely adequate basis for first selection, that there is sufficient genetic variation to allow great improvement in yield, that measured yield was the most effective measure of improved yield, and that family selection is not likely to be more effective than selection among individual genotypes. A suggested plan of recurrent selection for fruit yield was given.
Another notable publication is: "Genetic variation in an asexual species, the garden strawberry," Genetics 43, 634-646, 1958. Comstock, R.E., et al.
There are five agencies in the United States doing active breeding of strawberries on the Pacific Coast and all have long-continued programs. In Oregon and Washington the objectives are similar and the work closely coordinated. In general, the work of the California Strawberry Institute and of the California State Experiment Station is likewise coordinated and with similar objectives. In Alaska work is under way at the College Station near Fairbanks in the interior, and some testing of selections is being done at the Palmer Station, on the coast. A sixth agency, the Canadian Agricultural Experiment Station at Agassiz, British Columbia, also has strawberry breeding with objectives similar to those in Oregon and Washington, with emphasis on resistance to red stele and on hardiness (see Canada).
About 95 percent of the Oregon and Washington strawberry crop is produced for commercial processing, these two states producing the world's largest volume of frozen strawberries. The annual production is about 100,000,000 pounds from about 24,000 acres and the harvest season is June 5 to July 25. Fifty to 60 percent of the crop is frozen in 10 to 16 oz. dessert packages and the rest goes for preserving, ice cream, and institutional trade. From about 1905 to 1955, Marshall was raised on 90 percent of the acreage. Beginning in 1908, barrels of frozen berries were shipped to eastern preservers. Later, freezing in small containers developed. When prices dropped after World War II, higher yielding varieties were necessary and in 1950 the Northwest was introduced -- a firmer berry with a much heavier yield and more tolerant of virus diseases. It composed 75 percent of the acreage in 1962 and was replacing Marshall rapidly. In 1962 Marshall made up 15 percent, Siletz 6 percent, Puget Beauty 3 percent, and others 1 percent of the acreage. Breeding programs in the two States have similar objectives -- high yield, resistance to plant diseases, and high processing quality.
The work at the Oregon Station was begun in 1911 and continued to 1918 by V.R. Gardner, and again started by C.E. Schuster in 1920. It was made cooperative with the U.S. Department of Agriculture in 1928. When Schuster began nut research in 1930, the work was continued by George M. Darrow, 1930 to 1932, and then by George F. Waldo, 1932 to present. Gardner used the native ovalis and probably F. chiloensis in crosses with named varieties, with the objectives of superior shipping varieties. Schuster was breeding for a canning variety at the beginning, and obtained the Corvallis (Marshall x Ettersburg 121) from his first crosses in 1920. Later the work, in cooperation with the U.S. Department of Agriculture, was expanded with the objectives of originating better freezing and preserving varieties as well as better shipping varieties. In all, Schuster grew about 50,000 seedlings. He used F. ovalis and chiloensis in his later crosses and their use was continued in later years, but not to obtain shipping varieties. Waldo has named the Brightmore (1942), Siletz (1953), and Mollala (1961) varieties for their freezing qualities. Since 1944, breeding for red stele root disease resistance has been a primary objective and from 1944 through 1963 a total of 240,948 seedlings were grown in infected soil and examined for red stele. Both Siletz and Mollala were selected from this work and are resistant to this disease. Siletz is the standard variety for soils where red stele may be serious in Oregon, Washington, and British Columbia. In some places after a few years in the same soil new races of the red stele organism appear that can infect even Siletz. Waldo has used selected chiloensis and ovalis more than most breeders in his crosses.
N.E. Hansen (1907) in 1895 collected wild strawberries (virginiana) near Brookings and later obtained plants from North Dakota near Manitoba. These were compared with a large number of varieties at Brookings in 1899 and 1900 and found much hardier. Hansen's first crosses were made in the winter of 1899-1900 and others the following and succeeding winters. Eight thousand seedlings were planted and about 225 selections made. All seedlings endured -40° F. with no snow cover. Two were sent out for trial beginning in 1905 as South Dakota #1 (Jessie x Manitoba wild) and #2 [Glen Mary x Cavalier (North Dakota) wild]. Though hardy at the station, they were injured at some other places. Many thousand seedlings, produced by backcrossing selections to their parents, were grown. They seemed less hardy than the F1, but the non-hardy were weeded out by winter's cold. Dakota #1 became known as Dakota and was about one inch in diameter, too small to be grown except where the other varieties were not hardy. No breeding has been done by the South Dakota Station in recent years.
Strawberry breeding began in 1928 and has continued to the present. Its objectives have been to obtain attractive, firm, high-flavored varieties suitable for processing and shipping that are resistant to leaf and root troubles (Drain, 1934). Five varieties have been named: McClintock (1932) (Aroma selfed), Tennessee Supreme (1940) [Missionary x Howard 17 (Premier)], Tennessee Shipper (1941) (Missionary x Blakemore), Tennessee Beauty (1942) [Missionary x Howard 17 (Premier)], (Fig. 15-1), and Tennessean (1950) (Tenn.-230 x Tenn.-586). Of these, two are important, Tennessee Shipper (a backcross of Blakemore to Missionary) and Tennessee Beauty [Missionary x Howard 17 (Premier)], the former as a parent for firmness, the latter for its productiveness and commercial use. Under the general direction of B.D. Drain, crosses were made at the main experiment station at Knoxville by E.M. Henry in 1933. The seedlings fruited and selections were made by him in 1935. About 12,000 seedlings had been fruited by 1935 when the work was moved to Jackson, Tennessee, where the selections were retested. L.A. Fister and Drain made the final selections and naming. Strawberry breeding has been continued at the Jackson branch; more recently by J.P. Overcash (1942-1945), E.H. Hanchey (1946), P.L. Hawthorne (1947), and W.E. Roever (1948 to present). Now the breeding work has been moved back to Knoxville with Roever in charge.
In "Some strawberry breeding progeny data," by B.D. Drain and L.A. Fister, data are given on characteristics of large selfed populations of Klondike and Aroma, small numbers of Blakemore selfed, and on intercrossing Aroma and Klondike, Blakemore and Aroma, and Dorsett and Aroma. Selfed Blakemore had 14.2 percent highly flavored seedlings, Klondike 8.0 percent, and Aroma 1.1 percent. Selfed Blakemore had 83.7 percent of seedlings free of leaf blight, while Missionary had 63.3, Klondike 67.4, and Aroma 66.3 percent free. Blakemore x Aroma had only 7.5 percent high-flavored, Dorsett x Aroma had 16.7 percent and Klondike x Aroma 12.7 percent. Selfed Klondike had 6.1 percent vigorous plants, Aroma selfed 4.4 percent, and Blakemore selfed 6.8 percent, while Klondike x Aroma had 54.3 percent and Blakemore x Aroma had 23.0 percent vigorous. Missionary x Howard 17 (Premier) had only 12.6 percent firm vs. Missionary x Fairfax 31.2 percent firm-fruited.
In "Strawberry breeding and the inheritance of certain characteristics" (1942), Overcash, Fister, and Drain reported on plant and fruit characteristics of crosses between Tennessee selections and between Tennessee selections and varieties. The cross of Tenn.-384 (Missionary selfed) x Tenn.-388 (Fairfax selfed) gave a vigorous progeny and many good-flavored seedlings. Eighteen percent of the progeny was saved for further testing.
In 1933 and 1934 crosses were made by Mortenson to obtain varieties that would produce sufficient runner plants able to survive under the high temperatures of south Texas. In 1938, eight selections were still being tested and three were named and introduced. Alamo (1937) was Blakemore x Ettersburg 80, Ranger (1937) was Texas x Missionary, and Riogrande (1937) was Blakemore x Ettersburg 80. Of these, Ranger is still being raised in south Texas.
In Burlington, Dr. Charles Blasberg started strawberry breeding in 1945 and continued until his death in 1961. A main objective was late varieties for northern regions; later objectives were both early and late varieties. A number of selections of F. virginiana were used in breeding. A promising cross was U.S.-3366 x Temple. Selections from Blasberg's work are being tested currently under the direction of R.J. Hopp and B.R. Boyce.
In "Sterility of strawberries; Strawberry breeding" (1923), Cummings and Jenkins reported a study of the inheritance of sterility in strawberries. In crosses of the pistillate with perfect-flowered, 54.7 percent of the seedlings were perfect-flowered. Studies of inheritance of fruit characters were made with very small numbers, but large fruit size seemed to be clearly heritable.
The work at this station in Puyallup was begun by a graduate student, M.B. Hardy (1929-1931), and has been continued since 1932 by C.D. Schwartze, assisted 1940-1957 by Arthur S. Myhre. The objectives were firm, high yielding, red-fleshed, virus-tolerant, red stele-resistant varieties for freezing and preserving. The first variety, Northwest, was the result of a cross of 2 U.S.-Oregon selections: Brightmore x U.S.-Oreg.-456. Puget. Beauty (I 956) is a cross of Sparkle x U.S.-Oreg.-1765; Cascade (1961) is Shasta x Northwest; and Columbia (1961) is Wash.-157 x Wash.-175 (both selections resulting from crosses of U.S.-Oregon unnamed selections). The Northwest variety by 1962 constituted about 75 percent of the acreage in strawberries in Oregon and Washington, and it is also grown in British Columbia. It is much more productive than Marshall which it is replacing, and much more tolerant of virus. It is also firmer, has good processing qualities, and in 1962 was processed in larger quantity than any other variety in the world and constituted the largest acreage of any variety in the United States. It is not resistant to the red stele root disease, while Marshall is somewhat resistant. The new Columbia is similar to Northwest in processing qualities, but in addition is resistant to some races of red stele and to mildew and is highly tolerant of virus diseases. It ripens one week later than Northwest and is reported as somewhat resistant to the Botrytis fruit rot or gray mold. About 150,000 strawberry seedlings have been grown in the breeding program.
Up to 1962 it was estimated that 273,000 tons of the Northwest had been produced with a total farm value of $71,000,000. For 1962 the total was about 52,000 tons with a farm value of 513,500,000 and a processed value of $18,720,000. From the beginning, in the 20 years before the Northwest was released, a total of $100,000 may have been spent on the strawberry breeding work by the Washington Station.
Professor R.H. Roberts, now emeritus, has done limited strawberry breeding for many years at Madison and in 1950 he introduced two varieties, Wisc.-214 and Wisc.-537. Another, Wisconsin Queen, was introduced in 1959. These have been grown to a limited extent only. No virus-free stocks are known. Wisc.-214 was introduced for its large, attractive fruit which freezes well. Its parentage is Corvallis x Wisc.-7128 [Wisc.-78 (Beaver x Howard 17 (Premier) x Wisc.-134 (Vanguard x Howard 17 (Premier)]. Wisconsin Queen (Wisc.-214 x Wisc.-6-2) was introduced in 1959 for its attractive, good-flavored fruit, adapted to freezing.
Beginning in 1956, F.A. Gilbert, who in New Jersey made the cross and selected the Jerseybelle, has made crosses and fruited about 17,000 seedlings at the University Farm at Sturgeon Bay. Up to 1963, 205 selections in all have been made, 50 are under advanced tests, and three are being studied for possible introduction. The objectives are for large size, high yield, firm fruit, freezing quality, and high flavor.
Important varieties grown in the state are Robinson, Catskill, Howard 17 (Premier), and Sparkle. Wisc.-214 and Wisc.-537 are grown to a limited extent. The newer varieties Jerseybelle, Earlidawn, and Surecrop are being suggested for trial in some areas.
Collections of native strawberries (mostly ovalis) for possible hardiness in breeding was begun by A.C. Hildreth as early as 1932. Extensive systematic collections took place in 1936 after the severe winter of 1935-1936 had killed, or badly injured, all of the more than 150 commercial varieties, while the collected native plants remained uninjured. In all, about 42,000 plants from more than 1,100 localities in Wyoming, Colorado, Montana, New Mexico, and Utah were collected and planted in trial plots at Cheyenne, the U.S. Department of Agriculture Station. None was suitable for cultivation but they showed "extreme variations in horticultural characters, differing in size, shape, color, and flavor of fruit and in season of maturity, fruiting habit, prolificacy, tendency to produce runners, resistance to disease, and tolerance to soil alkalinity" (Hildreth and Powers, 1941). Some were everbearers, others June bearers. Most of the ovalis were pistillate or staminate, but a few were true perfect-flowered. Some showed considerable drought resistance and the majority proved hardy without protection.
Under Drs. Hildreth and Powers, during the winter of 1937-38, three varieties, Gem, Dorsett, and Fairfax, were crossed with three different collections of F. ovalis selected for winter hardiness, one of which had high flavor and a second larger than average size. The F1 varied greatly. During the winters of 1938-1939 and 1939-1940 over 80 percent of the Dorsett and Fairfax and about 30 percent of the Gem plants were killed. In contrast, there was no appreciable killing of the F1 nor of the native plants. In fruit size the F1 were mostly intermediate, but ranged from as small as the smallest ovalis to nearly as large as the Fairfax, and some, with Fairfax and Dorsett as one parent, were superior in sweetness and flavor to either variety. Powers concluded that ovalis could be used to improve the cultivated strawberry in earliness, runner production, sweetness, flavor, and aroma. Different ovalis collections had different values as parents in crossing with cultivated varieties. The backcross method seemed to offer the greatest possibilities for the most rapid success of a breeding program. Double crosses were shown to offer far more promise than F2 populations. On the average, 1 in 100 seedlings-recombined six desirable characteristics: winter hardiness, large fruits, vigorous plants, high runner production, early maturity, and high flavor. Winter hardiness and production of many runners were almost completely dominant.
From this work, three varieties were released in 1944, one in 1948, two in 1954, and one in 1956, all for home garden use. The three varieties -- Cheyenne 1 (Dorsett x F. ovalis), Cheyenne 2 (F. ovalis x Fairfax), and Cheyenne 3 [Fairfax x (Fairfax x F. ovalis)] -- were introduced in 1944 as high-flavored varieties to cover a season of over a month, but were much smaller than the Fairfax. In 1948, the Sioux [(Fairfax x F. ovalis) x Fairfax] was introduced in cooperation with the North Platte Experiment Station of Nebraska. It was very hardy, soft, productive, high-flavored, but also smaller than commercial varieties. These are not now in the trade.
Three everbearers have since been introduced: Radiance [Montana x Cheyenne I (F. ovalis x Fairfax) x Fairfax] and Arapahoe [(Cheyenne I x ((F. ovalis x Fairfax) x Fairfax)) x (Rockhill x Cheyenne 3)] are very hardy everbearing varieties and were introduced in 1954. The berries of these are as large as commercial varieties. They are drought- and alkali-tolerant and the flowers are somewhat frost-hardy. Ogallala, introduced in 1956 (Rockhill x Cheyenne 3) x (Midland x Cheyenne 2), a third everbearer of high quality, was selected from 4,300 seedlings that were sent to North Platte, Nebr., Station where they were grown by Glen Viehmeyer. It is also hardy and is drought-tolerant, with berries the size of Fairfax. It and the other two everbearers seem adapted to eastern Colorado and to western Kansas north to Canada. More than most others, the work of Powers indicates the methods by which wild native selections can be utilized by breeders (Powers, 1944, 1945).
Dr. Powers was in other work from 1942 to 1946, during which time Dr. D.H. Scott was in charge of the strawberry breeding. Dr. Powers left finally in the fall of 1954; the work was continued by E.D. Krouch to January 1957, then by Brown to 1961, and since then by G.S. Howard. Since 1956 about 32,000 seedlings have been grown, 254 selections made, and a few are being more widely tested. The breeding work was still being continued in 1964.
In Canada the total acreage planted to strawberries in 1961 was given by the census as 13,051 acres, as 15,853 in 1951, and as 10,652 in 1941. Imports in 1961 were 25,140,820 pounds as contrasted with the 30,112,000 pounds produced in Canada. The acreage by provinces was:
|Prince Edward Island||-- 682 acres|
|Nova Scotia||-- 703 "|
|New Brunswick||-- 557 "|
|Quebec||-- 4,296 "|
|Ontario||-- 4,381 "|
|British Columbia||-- 2,253 "|
Ripening begins about June 10 in Ontario and British Columbia, and in Nova Scotia and Prince Edward Island extends into August. The major production area of British Columbia is the Lower Fraser Valley with 1,600 acres in 1963.
Until about 1950, when some of the varieties bred at Ottawa and Vineland began to be grown in Eastern Canada, and British Sovereign became the dominant variety in British Columbia, the varieties grown in Canada were much the same as those grown in the northern part of the United States. In 1897 Haverland, Warfield, Crescent, and Wilson were considered the chief varieties, and Parker Earle, Gandy, and Williams the favorite late ones. In 1909 Bederwood, Splendid, Warfield, Williams, Greenville, Bisel, Sample, Buster, Pocomoke, and Parson were recommended. In 1919 the chief varieties grown were: Maritime Provinces, Dunlap, Splendid, Glen Mary, Sample, Warfield, Belt; Quebec, Dunlap, Parson, Splendid, Bederwood, Sample, Pocomoke, Warfield; Ontario, Parson, Glen Mary, Williams, Dunlap, Bederwood, Splendid, Howard 17 (Premier), Sample, Enhance; Prairie Provinces, Dunlap, Dakota, Bederwood, Haverland, Warfield, Tennessee Prolific; British Columbia, Magoon, Dunlap, Marshall, Paxton.
In 1950 varieties grown were:
Nova Scotia: Howard 17, Dunlap, Catskill, Jessie.
New Brunswick: Howard 17, Dunlap.
Prince Edward Island: Dunlap, Tupper, Louise, Elgin.
Quebec: Howard 17, Mackenzie, Dunlap, King, Louise, Elgin.
Ontario: Howard 17, Dorsett, Dunlap, Parson, Fairfax, Valentine.
Manitoba: Dunlap, Glenmore, Gem,* Sparta.*
Saskatchewan: Dunlap, Dakota, Gem,* Sparta.*
Alberta: British Sovereign, Dunlap, Howard 17, Gem,* Mastodon.*
British Columbia: British Sovereign, Marshall, Magoon; Dunlap, Gibson,
In 1962 the varieties recommended were:
Newfoundland: Howard 17, Dunlap, Sparkle, Louise, Red Rich.*
Prince Edward Island: Cavalier, Dunlap, Redcoat, Catskill, Sparkle, Guardsman, Red Rich.*
Nova Scotia: Cavalier (14 percent), Catskill (25 percent), Redcoat (31 percent), Sparkle (29 percent), Surecrop (promising), Gem,* Red Rich.*
New Brunswick: Cavalier, Redcoat, Grenadier, Sparkle, Catskill, Guardsman, Red Rich,* Gem.*
British Columbia: Northwest, British Sovereign, Puget Beauty, Marshall, Agassiz; Northwest 60 percent and British Sovereign 40 percent of acreage.
Quebec: Cavalier, Redcoat, Sparkle, Guardsman.
Ontario: Redcoat (for main crop); Earlidawn, Erie, Catskill, Sparkle, Cavalier, Guardsman, Howard 17 (Premier).
Since 1960, Cavalier and Redcoat, both bred at Ottawa, have rapidly become the leading varieties of eastern Canada. In 1887 W.W. Hilborn reported having about 90 seedlings in the test planting at the Central Experimental Farm at Ottawa. As early as 1889, 650 seedlings were fruited there and 40 saved for further testing. John Craig was horticulturist in charge from 1890 to 1897, and in 1897 about 1,400 seedlings were raised. In 1898 W.T. Macoun became horticulturist and selections were made. M.B. Davis became his assistant about 1915 and took over the breeding work soon afterward. One-half acre was in breeding plots in 1917. Davis was made Dominion Horticulturist in 1933. Dr. A.W.S. Hunter took over the strawberry breeding in 1936 and L.P.S. Spangelo succeeded him, making his first crosses in 1949. Ray Watkins joined the breeding staff in November 1963.
The wild strawberry, F. virginiana, is native in Canada as far north as the 64th parallel, the latitude of Iceland, Stockholm, and Helsinki. Selections of native virginiana plants from Nova Scotia, New Brunswick, Ontario, Manitoba, and British Columbia have been used in crosses. The objectives in breeding were hardier varieties for northern latitudes, sweeter berries with higher aroma. Varieties were introduced as early as 1913. Presently, objectives include increased yield, firmer and more attractive berries, good dessert and processing quality, easy capping, and resistance to foliage diseases. Commercial varieties and Ottawa selections are used as parents. Promising crosses have been Sparkle x Valentine, Howard 17 (Premier) x Fairfax and x Valentine, Valentine x Fairfax, Claribel x Sparkle, Howard 17 (Premier) x Temple, Temple x Dresden. One variety, Louise, seems of some importance. The others failed, probably because of infection with virus diseases. Louise (1942) (Ettersburg 811 selfed) is a pistillate, late, attractive, medium to large berry of good dessert quality. It is very susceptible to leaf scorch and leaf spot, and virus-free stock is not available. It is grown to a very limited extent.
In 1957, four new varieties -- Cavalier (Valentine x Sparkle), Grenadier (Valentine x Fairfax), Guardsman (Claribel x Sparkle), and Redcoat (Sparkle x Valentine) -- were named and introduced. Guardsman, the latest and best in dessert quality, has been highest yielding, but Redcoat is a close second. Cavalier has been the best for early ripening, and Redcoat the most attractive and important commercially.
Cavalier is a very early, attractive variety whose fruit is much firmer than Catskill, Dunlap, or Howard 17 (Premier) (in Canada, but not in New York), and earlier than Howard 17 (Premier), good for dessert and processing. It is resistant to Verticillium, susceptible to mildew, scorch, and spot, and has dead caps in New York. It drops off in size too quickly.
Grenadier is a mid-season, dark red, very firm variety about the size of Howard 17, with good dessert and processing quality, but susceptible to mildew. The calyx is clasping like its Fairfax parent, but the berry is more tart and deeper red within. Like Cavalier it drops in size too quickly.
Guardsman is a very late, attractive and firm variety which is highly acid until ripe and then is high-flavored and good for processing. While resistant to some races of red stele and mildew, it is susceptible to Verticillium. It too drops in size quickly.
Redcoat is a mid-season, very attractive, glossy, light red variety with firm meaty flesh, good dessert quality. It is fair for processing, but susceptible to Verticillium and leaf spot. It is resistant to mildew. Because of its very productive plants, large average berry size, very attractive, glossy, bright red appearance, firm flesh and good shipping quality, equal to that of Sparkle, Howard 17 (Premier), and Dunlap, it is already the leading variety of eastern Canada.
Inbreeding has received considerable attention at this farm (Spangelo, 1958). As early as 1920 Parson, Bederwood and Valeria were being selfed and an F2 generation fruited in 1924. Beginning in 1949, inbred lines of Howard 17, Sparkle, and Fairfax have been carried to the S5 level. Valentine was crossed with seven Howard 17 (Premier) S2 clones and three Sparkle S2 clones, and in 10 of the 12 progenies the percent of selections was higher than in progenies obtained by crossing the originals. Phenotypes as a measure of genotypes of selfed lines is under study. For 1964 there were 17 S5 progenies of Howard 17 (Premier) and two of Sparkle to be fruited.
For the University of Minnesota in 1963 Spangelo, in his Ph.D. thesis entitled "Combining ability in strawberries," reported on selfing and intercrossing five varieties, and on an S2 of Early Bird (1963). Leaf scorch resistance and fruit quality did not show combining ability, but leaf spot resistance, number of runners, early ripening, fruit size, appearance, and firmness did. Accordingly, comparisons of self progenies can be used for selecting parents for any of these characters. The best cross indicated for several characters of the varieties tested seemed to be Howard 17 (Premier) x Fairfax followed by Fairfax x Dresden and Howard 17 (Premier) x Dresden.
In 1950 a study of the possibility of growing seed-propagated, instead of clonally propagated, varieties was begun. Seedlings of some crosses were quite uniform, and commercially acceptable, especially Sparkle X Valentine. At the same time isolation of variety testing, and control of vectors of virus was begun, since indexing for virus showed that most previous selections and varieties were completely or partially virus-infected.
Some publications are:
"Suggested infection scales for roguing strawberry seedlings susceptible to M. fragaria and D. earliana," Phytopath: 93:345-347. 1953, by L.P.S. Spangelo, and A.T. Bolton.
"Studies in strawberry bud differentiation," Canada Department of Agriculture Bul. 110, 1929, by H. Hill, and M.B. Davis, 1929.
The first sign of flower bud differentiation was noted September 19 in the Pocomoke variety. Runner plants rooted on September 19 showed initial flower bud stages in three weeks, and those rooted on October 10 showed initial stages October 24.
KENTVILLE, D.L. Craig has reported two phases of the breeding program here. (1) Inbreeding for seed-produced varieties of uniform type and (2) variety crossing for improved early and late maturing varieties. Inbreeding started in 1953 and 40,000 selfed seedlings had been evaluated by 1963. From 10 named varieties there were 30 S3 lines, 184 S2 lines, and 53 S1 lines. Variety crossing started in 1951; 10,000 seedlings had been evaluated by 1963 and two appeared promising, one having a season like Sparkle and the other later.
D.L. Craig, E. Aalders, and C.J. Bishop (1963) have reported on their inbreeding up to 1963. They state their outlook as follows: "As the available varieties become more and more highly selected and further improvement becomes progressively more difficult, larger and larger populations are necessary.... One phase of the strawberry breeding program at Kentville is, therefore, presently aimed at surpassing this plateau of breeding advancement through development of a strawberry variety of desirable type which can be grown from seed." The project was begun in 1953. Five selections were made of each of two crosses, Valentine x Sparkle and Valentine x Fairfax, and then all selections of each cross were crossed with all others. The No. 3 selection of the first cross x No. 4 of the second was judged the best. Then 500 selfed seedlings of each of these (No. 3 and No. 4) were grown and six selections of each made. Each of these six selections of No. 3 selfed was crossed with each of the six selections of No. 4 selfed, then the two best of these selections, as judged by their seedlings, were crossed. Finally, 30 feet of matted row of each of four sets of seedlings was compared as follows:
|FRUIT RATING||PLANT RATINGS|
|(1 to 5) |
Uniformity of Appearance
|Sparkle x Fairfax||26.5||2.55||3.31||78.8||88.6||76.6|
|F1 of original selection||36.7||2.80||3.40||83.1||82.7||78.2|
|F1 of sibs||38.5||2.89||3.72||88.2||90.2||84.2|
|F1 of selfs||40.8||3.24||4.26||92.2||94.3||90.5|
A consistent improvement in yield, fruit uniformity, and appearance, in plant stand, in health of foliage, and in uniformity of foliage was obtained. Aalders and Craig (1964) reported that in 1964 the inbreeding then involved 32 S4 lines, 180 S3 lines, 51 S2 lines and 2000 S1 seedlings. The recurrent reciprocal selection program was at the S2 level of inbreeding and test-crosses to Select S2 parents with superior combining ability were being planted. Acadia (Sparkle x Redcrop) from the regular crossing program was named in 1964.
Strawberry breeding was carried on at the Saanichton Experiment Farm, 1935 to 1955, by E.R. Hall and 1955 to 1960 by J. Harris, when the work there was discontinued. No variety was named from this work.
AGASSIZ. At the Canadian Department of Agriculture Farm at Agassiz the work was started in 1946 by T. Anstey and continued by J.A. Freeman until 1959, and since then by H.A. Daubney. Present objectives are to originate varieties (1) of high yields and high quality, especially for the processing (freezing) trade which uses 90 percent of the crop, (2) with resistance to red stele races prevalent in British Columbia, (3) with resistance to mildew, along the lines of Puget Beauty and Siletz, (4) with sufficient winter-hardiness. Northwest is ideal for frozen pack, but is not fully hardy and is susceptible to red stele and mildew. British Sovereign, of high flavor, is not suitable to freezing and is susceptible to both red stele and mildew. Siletz is resistant to some races of red stele but lacks high flavor. Agassiz was released in 1956. It is superior for freezing, is winter hardy, but susceptible to red stele and mildew. It is grown to a limited extend in the Salmon Arm area because of its preserving quality. Puget Beauty is high flavored, winter hardy, resistant to mildew, but susceptible to red stele and not a reliable yielder. Since 1959 between 15,000 and 20,000 seedlings have been screened each year for red stele and mildew resistance (Daubney, 1961). About 3,000 screened seedlings were planted in the field in 1963. Fifty selections from the 1959 crosses and 80 from the 1960 crosses are being retested.
Tests of sources of red stele resistance and the use of these sources in breeding are considered of primary importance. Additional collections of F. chiloensis from the Pacific beaches are being made for study. The Yaquina clone of F. chiloensis for red stele resistance, Puget Beauty for mildew resistance, and Puget Beauty x Northwest for fruit, have been outstanding. Close cooperation with Schwartze, of Puyallup, Washington, and Waldo, of Corvallis, Oregon, is maintained.
"Resistance to Verticillium wilt in F1 generations of self-fertilized species of Fragaria," Can. J. Bot.: 36, 1958, by W. Newton and M. Adrichen.
Selfed seedlings of the species vesca, vesca var. bracteata, virginiana, orientalis, ovalis including yukonensis, and chiloensis were tested for resistance to Verticillium wilt. No resistance was found in the seedlings of vesca or virginiana. Tolerant seedlings of orientalis were found and resistant seedlings, as well as tolerant seedlings in ovalis, ovalis yukonensis, and chiloensis.
"Effect of parentage in breeding for red stele resistance of strawberries in British Columbia," A.S.H.S., 84, 1964, by H.A. Daubney.
Daubney evaluated 25 parents from the following four sources of resistance, Aberdeen, Frith, F. chiloensis, and F. virginiana, as well as Magoon, Perle de Prague, and Oberschlessein of unknown origin.
Strawberry breeding at the Vineland Station began in 1913 and has been continued to the present, although no crosses were made in 1916 and 1921, or from 1931-1939. Five breeders have been successively involved in the work: F.S. Reeves, 1913-1922; W.J. Strong, 1921-1948; J.F. Brown, 1949-1956; E.A. Kerr, 1956-1958; and C.L. Ricketson, 1958 to present. The early objectives were large size, better flavor, greater yield, firmer, and more attractive berries. Early Ozark was the outstanding parent. Four varieties were introduced: Vanguard (Pocomoke x Early Ozark) in 1924, Vandyke [seedling 1467 (Dunlap seedling) x open] in 1928, Vanrouge (seedling 180,115 x Bliss) in 1938, and Valentine [Howard 17 (Premier) x Vanguard] in 1941. Seedling 180,115 was Admiral x 1563 (Dunlap x Early Ozark). Crosses for the first two varieties were made by Reeves and the next two by Strong. Only Valentine was important, because it was very early, large, soft but resistant to gray mold (Botrytis). Valentine is no longer grown commercially in Ontario, but it is one parent of Cavalier, Grenadier, and Redcoat, of the Ottawa Station, and is an important parent in other countries. All selections previous to 1958 have been discarded because of virus infection. Up to 1944, 37,555 seedlings had been fruited. The objectives in 1944 were better early varieties, higher flavor through use of English varieties, easy hulling, better preserving qualities, resistance to root rot and suitability to quick freezing. Present objectives of Ricketson are high yields and higher flavor, especially for preserving. Since 1958 some 3,790 seedlings have been fruited and 85 selections are still under test. About 10,000 seedlings were to be set in the field in 1964.
As in other Prairie regions with extremes of drought and temperatures, hardiness is all-important. Although only about one hundred and twenty acres of strawberries are grown in Manitoba, they are an important fruit for the home garden and small market gardener. Throughout more than forty years varieties from other areas have been tested for hardiness at the Dominion Research Farm at Morden. Dunlap, tested as early as 1920, proved a reliable variety and Howard 17 (Premier) has also been widely grown.
Up to 1950 Dunlap, Gem, Howard 17 (Premier), Sparta, Glenheart, Arrowhead, Burgundy, Evermore, and Valentine were used extensively in breeding. Rockhill was used for its high flavor and everbearing habit, and Cheyenne 1 and Cheyenne 2 for their hardiness. Most selections were lost due to virus infection and no superior selections were found. A diallelcross system using Valentine, Glenheart, Sitka Hybrid, Robinson and Morden selections 65-54 is being tried. Progenies with the greatest mean hardiness had Glenheart as one parent.
W.R. Leslie was the breeder from 1926, when breeding started, to 1943, then C.R. Ure from 1943 to 1962; D.D.F. Williams under Dr. Ure from 1950 to 1956. H. Quamme is now in charge and is mainly testing varieties and selections from other areas.
Two private breeders have been active in obtaining new varieties for prairie areas. William Oakes, of Miami, Manitoba, now in his eighties, introduced 17 varieties from 1940 to 1950, of which two, Glenheart and Glenmore, are still of some importance because of their hardiness. Glenheart, everbearing of unknown parentage, introduced in 1946, is widely grown in Manitoba. Glenmore, a June bearer also of unknown parentage, is recommended still for both Alberta and Saskatchewan. A.J. Porter, Parkside, Saskatchewan, is still an active plant breeder. He introduced 6 varieties of unknown parentage between 1940 and 1960. His Sparta, an everbearer introduced in 1940, is still extensively grown as a commercial variety. Parkland, introduced in 1954, is recommended as a hardy everbearer for Saskatchewan, and jubilee as a hardy everbearer for Alberta and Manitoba.
R.E. Harris is in charge of strawberry breeding at Beaverlodge. Prior to 1954 some open-pollinated seedlings had been grown. In 1954 a study was begun of the combining ability of cultivated varieties and of wild x standard varieties. Two promising selections have been made. Mildew-resistant virginiana was crossed with standard varieties in 1959 to improve hardiness. Selfing, followed by intercrossing, was started in 1961.
Premier, Glenheart, and Sitka hybrids proved best for transmitting vigor, and Northerner for yield. Fairfax and Red Rich transmitted the largest number of desirable fruit characters. Glenheart x Cheynne 2 was the most promising cross for considerations of hardiness, vigor and large fruit.
Although so far north (55' 13"), with an annual rainfall of 17.5 inches, of which 5 inches runs off with the spring thaw, with temperatures from 98° to -53° F., and soil temperatures as low as 15 at 4-inch depth, F. Virginiana is native and abundant. Many collections of virginiana have been made. Even vesca is native, but it is not as abundant as virginiana. Critical temperatures for killing well-hardened plants in October ranged from -15 ° to 5° F. Crown hardiness is considered to be most important.
*By R.S. Bringhurst