Preservation and Utilization of Appalachian Crop Germ Plasm
By Elmer Gray December 1999 Appalachian Heritage (reprinted with permission)
Genetic Diversity, Erosion, and Preservation
The history of agriculture is one of decreasing diversity and increasing specialization. Prior to its beginning some 10,000 years ago, man obtained food products from numerous wild plants. In the early stages of agricultural development, more than 3000 species of plants were domesticated for food production, but during the ensuing centuries, especially the present one, diversity diminished and specialization increased. Today the plant agriculture which directly supplies 93% of our food is dependent upon 29 basic food crops for calories and protein and upon a similar number of vegetable and fruit crops for vitamins and minerals (Mitchell, 1983). Our highly specialized agriculture has reduced not only the number of crop species, but also the number of cultivars within the species. For example, in the United States more than half of the 1969 acreage of several crops--common bean, cotton, pea, potato, rice, and sweet potato-was planted with four or fewer cultivars per crop (Wilkes, 1983). Genetic diversity determines the boundaries of crop productivity and survival. Productivity is diminished when the genotype (variety of a plant) is unable to respond fully to the environmental potential and when the genotype fails to resist unfavorable environmental conditions. Examples of national disasters resulting from limited genetic variability have been documented for potato, coffee, wheat, and corn (Allaby 1977). But despite these examples of potential problems or even disasters, the genetic diversity of many crop plants is under serious threat of destruction (Hawkes, 1983). Crop improvement through breeding depends upon the variability resulting from mutation--that genetic variability accumulated in wild species at their centers of origin and at other long-established habitats. Plant domestication resulted in the formation of cultivars, or particular varieties which growers maintain and transmit from one generation to the next. Thus, in earlier, more traditional agricultural practices, the genetic diversity essential for plant breeding was maintained in wild plants as well as in domesticated varieties. The destruction of wild habitat, plant domestication, plant breeding procedures, and agricultural specialization have all contributed to the erosion of genetic reserves among crop plants. Moreover, the clearing of land for agricultural and industrial development fragments and isolates natural habitats, resulting in the disappearance of native plant species (Wolf, 1985 and 1987). The selection process involved in the development of different varieties and cultivars eliminates the less desirable genes and maintains more desirable ones. In the development of heirloom vegetables (varieties long associated with particular communities), less intensive selection over longer periods of time results in altered cultivated forms for a given family or community. On the other hand, variety development requires more intensive selection for genotypes that will perform over a wide geographic area. Development of such specialized varieties may involve the elimination of thousands of genotypes to find a few acceptable ones. Consequently (and paradoxically), success in plant breeding reduces the variability that made that success possible . To make matters worse, the practice of growing a single crop over extensive areas has contributed to the vulnerability of crops to diseases, pests, and adverse environments (Harlan, 1980). The high degree of specialization in modern agricultural production, marketing, processing, and consumption has, of course, resulted in specialized, narrow-based varieties. In fact, every major crop presently grown has a narrow genetic base and is therefore vulnerable (Ford-Lloyd and Jackson, 1986).
Partial Solutions To The Problem
Serious efforts to conserve genetic resources began with the Russian geneticist and plant breeder, N.I. Vavilov. In 1926, he proposed that crop improvement be based upon wide genetic variation. To this end, he collected cultivated plants and their wild relatives from most parts of the world, to provide gene pools from which cultivars could be developed (Ford-Lloyd and Jackson, 1986). Since its inception, the Food and Agriculture Organization (FAG) of the United Nations has expressed interest in genetic resources. During the 1950s and 1960s, panels of experts identified crops and geographical areas where threats of genetic erosion were greatest. In 1974, international genetic conservation activities were initiated with the formation of the International Board for Plant Genetic Resources (IBPGR). This organization, jointly sponsored by the World Bank, FAG, and the United Nations Development Program,is funded from several sources including the Rockefeller, Ford, and Kellogg Foundations, Regional Development Banks, and donor countries. The purpose of the IBPGR is:
to promote an international network of genetic resource centers, to futher the collection, conservation, documentation, evaluation and use of plant germ plasm, and thereby contribute to raising the standard of living and welfare of people throughout the world.
The IBPGR has developed a global network of gene banks, sponsored numerous plant collection missions, and established global priorities, for crops needing urgent action (Ford-Lloyd and Jackson, 1986; Plucknett, et al, 1987). In addition to the IBPGR, other genetic conservation agencies include national organizations such as the U.S. Department of Agriculture, land-grant universities, regional plant introduction stations, and private plant-breeding companies. Recent biotechnological developments offer promise for greater efficiency in the utilization of genetic variability. Genetic materials have been combined between species that could not be hybridized through traditional plant-breeding methods. This potential for combining genetic materials from unrelated organisms makes the preservation of genetic diversity all the more important. Ford-Lloyd and Jackson (1986) concluded their treatise on plant genetic resources with the warning that, "the future of mankind is linked with a continuing source of genetic diversity. This diversity cannot be created overnight; the combinations of genes which have accumulated over thousands of years can be lost forever unless we take measures to prevent this."
The Appalachian Crop Environment
The world's eight primary centers of plant origin are located in mountainous regions, between 20 degrees and 45 degrees latitude both north and south of the equator. However, none of the primary centers is located in North America (Ford-Lloyd and Jackson, 1486). Thus, few crop plants have been domesticated in the United States; instead, most crops have been introduced from other continents. Likewise, for crop improvement, wild relatives of the domesticated plants must be imported. The Appalachian region covers approximately 197,000 square miles, including all of West Virginia and portions of 12 other states--Alabama, Georgia, Kentucky, Maryland, Mississippi, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, and Virginia. The Appalachian mountain range, oldest in the United States, begins in Quebec's Gaspé peninsula and extends approximately 1500 miles southwestward, ending in Alabama and Georgia. Parallel with the mountain range are the plateau and valley ranges (Brooks, 1965). These physiographic regions are characterized by differences in geological formation, climate, and topography. The parental materials for the mountain soils consist of igneous and metamorphic rocks; whereas parental material for the plateau and valley soils consists of sedimentary rocks. Consequently, Appalachian soils have varying chemical and physical characteristics. Climate is the principal ecological force affecting agriculture. In the Appalachian region, annual precipitation varies from 40 inches at the northern boundary to 50 inches at the southern boundary. Annual precipitation may reach 80 inches at higher elevations of the mountains and plateaus. Temperatures in the Appalachian region are temperate. Most of the area is included within the 55-degree and 60- degree isotherms of average annual temperature (lines on a map which connect points on the earth having the same mean temperature); however, the northern boundary and higher elevations are included within the 50-degree isothermal range. In Appalachia the host line varies, too, the soil freezing to an approximate depth of three inches in the southern part of the region and to 15 inches in the northern latitudes and higher elevations (Winters, 1957). One of the most consistent physical features of the Appalachian region is its variable topography. The region is characterized by elevations higher than those of surrounding land forms. The highest mountain (Mount Mitchell in North Carolina) has an elevation of approximately 6,700 feet. Some of the plateaus have eastern elevations of 3,000-4,000 feet (Big Black Mountain in Kentucky), but blend into the prairie of interior America on the west. The northern portion of the plateau (Allegheny) was glaciated by the Wisconsin Ice Sheet. Moreover, the entire plateau is intensively dissected by streams that flow in different directions. The Shenandoah Valley, one of the world's longest mountain valleys, came into existence because the underlying limestone and shale were easily eroded. As a result, land areas separating the valley streams are decidedly rolling. In Alabama and Georgia the Appalachian mountains and valleys broaden and finally blend into the coastal plains (White and Foscue, 1946; White, Foscue, and McKnight, 1974). Clearly, the Appalachian region's diverse climate, soils, and topography provide a wide range of environmental conditions. According to Vavilov (1926), the micro-climates and isolated environ- mental niches associated with such mountainous areas are conducive to rapid differentiation of crop plants. Much of the region's latitudinal range (between 33 and 43 degrees north) is within the range in which the primary centers of plant origins are located, and its many micro-environments include the natural selection forces that effect changes in plant populations. In view of the wide variety of plant species adapted to the area, Brooks described Appalachia as "one of the vegetative wonders of the world" (1965).
Early Appalachian Agriculture
Human pilgrimages have contributed to migrations of crops and livestock, thereby increasing diversity through the addition of new or allied genetic materials to recipient populations. Columbus included seeds on his voyages to the Americas. During the sixteenth century, ships sailing to the New World were required to carry plant propagation materials and livestock (Plucknett et al., 1987). Naturally, European migrants brought most of the crop-seed and livestock that became the progenitors of American agriculture. In turn, increasing population and greater demand for agricultural land east of the Appalachian divide encouraged clans of families to collect their crop-seeds and livestock for the journey into and beyond the Appalachian Mountains. Central Appalachia (Kentucky, southern West Virginia, north central Tennessee, and western Virginia) was settled more recently than the northern or southern sub-regions. Following the settlement period (1800-1830), no significant migration came into the narrowing valleys (hollows). Each family saved its life-sustaining vegetables and corn seed-stocks from the previous year's crop. Since the families within a hollow formed a community to themselves, and there was little contact among families in different hollows, each clan's knowledge and resources came largely from its own members (Frost 1899). Central Appalachia remained isolated from the time of its initial settlement until the 1950s, when paved roads and improved transportation were extended into the more remote communities. During that period of isolation, there was little change in the internal approach to agriculture and little interaction with agricultural developments beyond the mountains. Rather, a folk agriculture flourished through the practice of transmitting knowledge orally and by customary example, from one generation to the next. This folk agriculture was both self-sufficient and self-contained. The 100 to 150 year period of isolation provided for Appalachian agriculture the most ideal conditions for both natural and artificial selection, resulting in distinct varieties of vegetables, fruits, ornamentals, and field crops. Many of these crops are now identified as "heirlooms" (just as families kept their heirloom tool and furniture). Such agricultural produce was a traditional expression of the mountaineer's pride and independence; and, thus, folk agricultural practices enhanced an already rich and varied environment. Since money and store-bought items were scarce, produce was commonly used as payment for work and as gifts to neighbors. Crop products provided individual identity for the grower. Vegetable and corn varieties were, without doubt, super abundant in the 1950s (the ending of the isolation period and beginning of the availability of commercial seed). By now, even though mountain farmers were reluctant to accept scientific agricultural practices developed outside the area, the number and diversity of varieties have diminished significantly. However, there is evidence that many of the heirloom varieties continue to be passed from generation to generation. Without question, more of the heirlooms are in existence now than will be in years to come, unless preservation is practiced.
The case for an Appalachian Seed Bank
In addition to the international network for conserving germ plasm (genetic materials), regional seed banks have been developed to enhance genetic diversity. Two notable examples illustrate the importance of such conservation developments. In Britain, protective seed laws make illegal the selling of cultivars not officially registered. Unlisted cultivars may be grown, but not sold. Inclusion in the registry requires that cultivar performance and genetic purity be officially sanctioned, thereby adding prohibitive cost to the marketing of heirloom varieties. In response, the Henry Doubleday Research Association (one of several concerned voluntary organizations, consisting of amateur gardeners who cooperatively grow and exchange local heirloom plants) laid plans to establish a central seed bank for maintaining traditional vegetables (Allay, 1977). Similarly, in Iowa, Seed Savers Exchange was founded to preserve the gardening heritage. During its first few years, the organization grew to include 550 members and published an annual catalog (256 pages), listing seeds offered by its members. As early as 1986 it was estimated that 250,000 seed samples had been exchanged among the members, and an associated seed bank included 4000 collections (Kane). Certainly, a seed bank should be established in Appalachia for the purpose of preserving the genetic materials of the region's crop species. Specific objectives to be attained through such a seed bank include:
a. identifying and collecting regional heirlooms; b. sharing heirloom propagation materials with other growers, both in and outside the region; c. growing and evaluating heirlooms at a central location; d. comparing heirlooms with introduced breeding lines and cultivars; e. making heirloom propagation materials available to public and private plant breeders; f. providing limited seed bank storage; g. sharing diverse materials with other seed-banks.
The seed bank should be located in the central Appalachian area because of its greater agricultural isolation, its larger number of small and part-time farmers, and the independence and self-reliance of the people. Although open to any local crops, and subject to changing emphases, early conservation efforts should be directed mainly toward beans, tomatoes, and corn, mainstays of traditional mountain agriculture. Moreover, continued production under existing cultural conditions should be encouraged, permitting further heirloom development while maintaining grower involvement and minimizing program costs. In this regard, grower interest groups should be established to broaden the base of participation and evaluation. However, a centrally-located seed bank will be necessary for the identification, evaluation, storage, and distribution of heirloom propagation materials. The seed bank would have to have either its own expertise in plant breeding, horticulture, plant physiology, plant pathology and soil fertility, or be connected with a college or university where such expertise is available. In either case, the seed bank would have to have a director and support staff for office and farm work. Other requirements would include limited land for growing plant collections, controlled humidity and temperature space for seed storage, computer and software for record keeping, farm machinery for field work, and greenhouse space for plant propagation. These expenses would have to be met through some combination of public financing and private donations, permitting the Appalachian crop germ plasm to be preserved and made available without charge. National and International genetic conservation efforts need to include as many gene pools as possible. The diverse combinations of physical environments and traditional agricultural practice make the central Appalachian region ideally suited for the accumulation of genetic diversity in its crops. Despite developments through much of this century in the technology and the business of American agriculture, the Appalachian people's links to their place and their past may help ensure the future for all of us.