The National Plant Germplasm System (NPGS) is a network of federal and state cooperative agencies which houses germplasm of economically important crops and their wild relatives. Curators are assigned to coordinate long term collections at facilities located throughout the country for optimum crop performance. Constant awareness of germplasm outside of the NPGS system will improve the scope and value of NPGS collections. This alternate source germplasm can reside in other national germplasm collections, in breeding and research collections, in botanical gardens and arboreta, and with private companies, organizations, or individuals. New plant explorations also continue to provide additional germplasm. Many organizations and individuals have begun compiling and publishing lists of germplasm sources. A summary of lists for temperate fruit and nut germplasm will be presented as an example. Compilations of this sort are extremely useful at the time of publishing but become outdated as listed sources change, or new sources are established. Periodic updating of published compilations are thus required. Contacts with Crop Advisory Committee members, plant researchers, and professional and amateur specialist organizations are also important sources of germplasm information.
Pyrus communis L. germplasm came to North America with early settlers. Pyrus cultivars have markedly declined since the turn of the century when more than 2700 unique Pyrus cultivars and 10,000 cultivar synonyms were noted. In 1956, 844 Pyrus cultivars and selections were widely available. Fireblight, Erwinia amylovora (Burril) Winslow et al. 1923, and lack of cold hardiness were main causes of cultivated germplasm loss. During June through December 1989, I resurveyed 37 State Agricultural Experiment Stations which had pear collections in 1956, to determine the present extent of their collections. Only four had more than 100 cultivars; 12 had 10 to 100 cultivars; 21 had less than 10. Experiment stations have decreased their collections because of funding cuts and program redirection. The National Clonal Germplasm Repository at Corvallis, established in 1981, has a collection of 811 unique cultivars and representatives of 26 Pyrus species. About 194 cultivars published in 1908 are in the NCGR collection. At least 424 of those listed in 1956 still exist. Oriental species and other foreign selections not previously available are actively being acquired. About 80% of the clones in the NCGR collection are virus negative; about 10 % reside in backup in vitro storage. Fireblight damage has not been observed thus far. With continued federal support, Pyrus germplasm availability should remain more stable than the decline seen in the last 90 years.
Kim Hummer and Donna Gerten
In commercial growing regions the bloom period for currants and gooseberries is critical to crop development because of potentially damaging spring frosts. Breeding programs in northern latitudes include selection for frost avoidance mechanisms such as late blooming tendencies. Corvallis climate is milder than Ribes production regions, with the average winter minimum temperature about 10C and the coldest recorded April temperature of -5C in 1926. The last spring frost occurs by April 14 on average. About 30 cultivars and species selections of currants and about that same number of gooseberries were evaluated for blooming and fruiting at the National Clonal Germplasm Repository. Dates of first bloom, last bloom, first ripening, and last ripening during 1987 through 1989 were collected. The longest ripening period, 93 days, occurred in 1989 on a selection of R. burejense F. Schmidt. The shortest ripening period in 1989 was 70 days, occurring in many black currant cultivars including Black September, Crusader, Coronet, and Invigo. These same cultivars required a range from 62 to 66 days to ripen m 1987. For the years examined thus far, the earliest ripening dates occurred in 1987, starting as early as Julian date 150; the latest ripening date (192, Julian) occurred in 1988. Data from 1990 will be presented. The climate in the Pacific Northwest is favorable for the production of currants and gooseberries.
Kim E. Hummer
Several species of Ribes have ornamental qualities worthy of consideration in residential and commercial temperate zone landscape plantings. Ribes sanguineum Pursh has been selected and cultivated throughout the Pacific Northwest, and boasts of early spring flowers of white, pink, or red. The two species of golden currants, R. aureum Pursh and R. odoratum Wendl. f., have brilliant yellow-fl owered racemes. Ribes species exhibit a broad diversity of plant habit and texture ranging from the upright 2.5 m, vigorous, and fully armed Menzieís Gooseberry, R. menziesii Pursh, to the prostrate shade-loving Crater Lake currant, R. erythrocarpum Coville & Leiberg. R. viburnifolium A. Gray remains evergreen in mild climates throughout the year. The foliage of some selections of R. americanum Miller and R. cynosbati L. brighten to a brilliant crimson red in the fall. The fall foliage of other species, such as R. hirsuta L., develop a continuum of color on their branches, from bright red at the apex, through orange and yellow to green towards the base. Spring bloom data and ratings of fall color for species in the Corvallis Repository collection will be described.
Kim E. Hummer
Kim E. Hummer
The pear, Pyrus L., originated in prehistoric times. Records of its cultivation date back 3000 years both in Europe, with the ancient Romans and Greeks, and in Asia, with the Chinese. Pear culture was significant in France and England by the 16th century. The European golden age of pear improvement occurred from the 17th through the 19th centuries. The pear genetic resource collection for the United States Department of Agriculture, Agricultural Research Service, National Plant Germplasm System is maintained at Corvallis, Ore. This collection preserves more than 2000 diverse pear accessions, represents 26 species, and includes more than 410 heirloom cultivars. At least 10 of the cultivars have obscure origins from the ancient Roman, Greek, or Chinese cultures. Another dozen are at least 400 years old, and more than 250 were introduced during the European golden age. Another 120 “antique” cultivars of the collection were introduced during the first half of the 1900s. The “big four” economically important Pyrus communis L. cultivars in the United States, `Bartlett', which originated in 1777; `Anjou', late 1700s; `Bosc', 1807; and `Comice', 1845; are also represented. Origin and background information for these heirloom clones is web accessible through the Germplasm Resource Information Network (GRIN) database. Although many ancient pear genotypes have been lost, the Repository staff continues to search for significant heirloom cultivars that are not yet represented. Besides having direct value in crop improvement, these plants are a significant part of our human heritage. Their preservation is a sacred trust.
Kim E. Hummer
Allan Stoner and Kim Hummer
The latter part of the 19th and the first several decades of the 20th century can be described as a “golden age” for plant exploration and collecting. During the initial years of this period, agricultural scientists from the United States and elsewhere devoted considerable resources to collecting potential new crops for farmers as well as superior plants or cultivars of the species that farmers were already growing. Over time, there was a shift toward collecting unadapted germplasm, or raw material that possessed traits that plant breeders and other scientists could use for cultivar improvement and other types of research. Although many institutions and individuals were involved in plant collecting during this period, the creation of the U.S. Department of Agriculture (USDA) Office of Seed and Plant Introduction in 1898, resulted in the largest single program devoted to plant exploration. This office employed many individuals, including David Fairchild, P.H. Dorsett, Frank Meyer, Walter Swingle, and Wilson Popenoe. These and many other individuals collected—and introduced into the United States—seeds and plants of thousands of fruits, vegetables, nuts, ornamentals, cereals, forages, oilseeds, and other types of crops. Although the mission of most of the plant explorations during this period was to collect any plants that appeared interesting or potentially useful, others focused on collecting targeted species. Much of the material collected during this era is still maintained by the U.S. National Plant Germplasm System (NPGS), and much more of it shows up in the pedigrees of cultivars grown by farmers and gardeners today. In addition to collecting plants for immediate and future use, scientists of this era, such as Nicolai I. Vavilov and Jack Harlan, contributed greatly to the understanding of the evolution of plants and plant genetic diversity, and the interdependence of plants and civilization.
Kim E. Hummer
The fruits of the earth have healed, nurtured, and intrigued humanity throughout history. Cultivated fruit species have complex genome that will continue to require the input of novel genetic resources. Prospecting for wild fruit species will continue. The global nature of science and commerce will drive the demand to expand available genetic resources for fruit improvement. New technologies will enable future explorers to reach remote sites and species. Recent advances, such as geopositioning and remote-communication devices, will be used to a greater degree for targeting specific collection sites and documenting records of origin. The sovereignty of countries over their plant genetic resources, as specified by the Convention on Biological Diversity and the International Treaty on Plant Genetic Resources for Food and Agriculture, will continue to be a cornerstone for negotiating bilateral agreements and plant exchange. Although this could be considered a limitation to plant exploration in some situations, global strategies now in conceptual infancy will be developed to encourage and support ex situ preservation and continued plant exchange for long-term conservation and humanitarian benefit.
Kim E. Hummer
The U.S. Department of Agriculture (USDA), Agricultural Research Service, National Clonal Germplasm Repository in Corvallis was established as the U.S. National Plant Germplasm System's berry genebank in 1981. Since then, the USDA has sponsored numerous explorations throughout the United States and foreign countries to obtain berry plant genetic resources. Species of Fragaria L. (strawberries), Ribes L. (currants and gooseberries), Rubus L. (raspberries and blackberries), and Vaccinium L. (blueberries and cranberries) are native to both domestic and international localities. With limited gene pools for cultivated strawberries, raspberries, and blackberries, expeditions have provided a wealth of genetic resources to expand opportunities for breeders to develop new cultivars. Particularly given the diverse species inherent in the development of cultivated blueberries, these trips have discovered unusual new blueberry relatives and forms available for expanding the range of production, increasing plant yields, and improving fruit antioxidant content. Along the way, new fruit species and new uses for known species were observed. Gathering the bounty of the world's berries resulted in encounters with diverse fauna, from snakes, bears, and bison to butterflies, mosquitoes, ticks, and chiggers. Avenging Toxicodendron species have added their mark on intrepid explorers. Remote sites with nothing but clear night stars and the satellite markers on the global positioning system offer radiant beauty and an abiding hope for the conservation of plant genetic diversity for all people for all time.