Submitted to: American Society of Agronomy Monograph Series
Publication Type: Book / Chapter
Publication Acceptance Date: 8/20/2003
Publication Date: 1/20/2004
Citation: Carter Jr, T.E., Nelson, R.L., Sneller, C., Zhanglin, C. 2004. Genetic diversity in soybean. H.R. Boerma and J.E. Specht (eds), Soybean Monograph, 3rd Edition, Am. Soc. of Agron., Madison, WI. 114 pp. Interpretive Summary: Before written history, Chinese farmers used genetic diversity found in the wild to produce the crop species that we now know as domesticated soybean (Glycine max (L.) Merr.). Continued farmer use of genetic diversity since domestication has improved the soybean crop to a remarkable degree, raising the yield of soybean over that of the original wild soybean by at least an order of magnitude, enhancing it's resistance to an array of important diseases, and adapting the crop to grow in extreme climates. In the process, ancient farmers developed a treasure trove of genetic diversity that has important implications to the present day. The premise for the present review of genetic diversity in soybean is that society's requirement for new cultivars can be best met through comprehensive and systematic use of the reservoir of genetic diversity that has been handed down by farmers through the millennia. There are four main aspects of genetic diversity: formation, collection, evaluation, and utilization. Each is covered in this review.
Technical Abstract: There are four main aspects of genetic diversity: formation, collection, evaluation, and utilization. Each is covered in this chapter. Before written history, Chinese farmers used genetic diversity to develop the species that we now know as a Glycine max. Following this ancient, and perhaps diffuse, domestication, soybean spread to diverse areas, a dispersion that required selection for regional adaptation. The results of this dispersion and selection is still evident in our current collections. Soybean germplasm collections exist in many countries and are quite extensive. The collections of other wild Glycine species are relatively small. Efforts should be made to collect accessions of these wild relatives and employ molecular genetic techniques in their characterization. Evaluation of genetic diversity is of paramount importance to its utilization. Evaluation of diversity is always a formidable task, especially given the immense sizes of the G. max collections. The advent of new genetic technology based on gene expression patterns, marker polymorphisms, or biochemical traits may facilitate screening the collections for useful alleles. The extent of utilization in soybean breeding varies widely by region and trait. A key factor driving utilization of exotic germplasm is potential benefit. Benefit can be quite apparent for characteristics such as disease resistance or specialty traits, but vague for yield or abiotic stress resistance. This has limited the use of exotic germplasm to improve complex traits in the North America. Despite the advent of QTL analyses, new procedures and technology will be required to effectively utilize the diversity available. Despite the key role of genetic diversity in the history of science and agriculture, scientists have recognized only in recent decades the significance of systematic collection and preservation of germplasm, and the importance of a comprehensive understanding of genetic diversity. The confluence of technology, genetic resources, and human need may make the efficient and effective utilization of genetic diversity one of the notable accomplishments of the 21st century.