Some of the newly acquired seeds of primitive varieties of Chinese soybeans.
(Photo by Charles G. Helm)
As abundant and widespread as soybeans are throughout Illinois and neighboring midwestern states, one might be led to believe that it is a crop native to this region. In fact, this couldn't be further from the truth. The true origin of soybean as a cultivated crop dates back over 3,000 years to barely recognizable types growing wild in China. Once domesticated into a manageable crop, the soybean was used by peoples of eastern Asia as a source of food, for medicinal purposes, and for animal feed for thousands of years prior to its introduction into North America. Soybeans were first grown in Illinois by John H. Lea in Alton in 1851.
The recognition of the potential of soybeans as a field crop by pioneering U.S. agriculturists in the late 1920s and early 1930s led to several important seed collecting trips to the Orient. Plant breeders have used these original seed sources, also referred to as germplasm, to develop most of the commercial soybean varieties used by growers today. While no one questions the success of soybeans as a crop and their enormous importance to U.S. agriculture and the economy, scientists are concerned about the limited genetic diversity within our commercial varieties. Fully 95 percent of all the genes in soybean varieties grown in the U.S. can be traced to a mere 35 ancestral lines from Asia. For varieties grown in Illinois, the situation is even worse: only three ancestors account for over 50 percent of the genes. Without the input of new genes, each generation of newly developed varieties actually becomes more closely related genetically. To continue improving our varieties, breeders must incorporate new genes into old varieties.
In 1992, the USDA Soybean Germplasm Collection, located at the University of Illinois campus in Urbana, with the support of soybean farmers and the agricultural experiment stations of Illinois and Iowa, negotiated the acquisition of over 1,000 primitive soybean varieties from central and south China. This is perhaps the most significant germplasm acquisition in over 60 years, representing not only a significant numerical addition to the collection, but also the potential of genetic diversity not previously available to U.S. scientists. China is the center of diversity of soybeans and this is the first time in history that we have access to large quantities of germplasm from these areas.
Some of the newly acquired seeds of primitive varieties of Chinese
soybeans.
(Photo by Charles G. Helm)
A diverse team of scientists in Illinois, Iowa, and other states is currently evaluating these primitive varieties for traits that could be used directly to improve U.S. soybean varieties. This comprehensive evaluation includes an assessment of insect, disease, and nematode resistance; seed composition; drought tolerance; agronomic characteristics; and yield. Studies of this nature are time-consuming and expensive, but nonetheless essential investigations.
For instance, Illinois Natural History Survey entomologists have collaborated with USDA geneticists and plant breeders since 1970 to develop high-yielding, insect-resistant varieties adapted to the Midwest. While this cooperative effort has resulted in the development and release of improved breeding lines with usable levels of insect resistance, yield levels in all resistant releases have been too low for direct use by growers. However, if new sources of soybean resistance to insect defoliators were identified from within these new accessions from China, a potential breakthrough in this resistance versus yield impasse might be possible.
During the 1994 and 1995 growing seasons, new germplasm accessions were screened for resistance to leaf-feeding insects in both field and laboratory studies. Seven lines with levels of resistance equal to currently available breeding lines were identified as a result of these efforts. Although insect resistance is only a small part of the development of genetically improved varieties, this information will be combined with results of the analysis of the other broad range of traits included in this study. Preliminary results suggest that looking back into the soybean's past may be the best route to future improvements of U.S. soybeans.
Charles G. Helm, Center for Economic Entomology and Randall Nelson, USDA Soybean Germplasm Collection
Next Article
Index
to This Issue
Index to
Survey Reports
INHS Home Page
Please report any problems with or suggestions about this page to:
inhspubs@mail.inhs.uiuc.edu
Subject: INHSPUB-00416
Last Modified 4/24/96