Genetic resources at risk: scientific issues, technologies, and funding policies. Proceedings of a symposium, American Association for the Advancement of Science annual meeting, San Francisco, California, USA, 16 January 1989.

Essential genetic stocks range from world germplasm collections of our major crops to genetic stock collections of experimental species such as Drosophila melanogaster. Not evely accession of every major and minor crop, nor even all genetic stocks of our most important food crops can be conserved indefinitely. Nor can evey ecological niche be protected, even though they may be harboringpotentially useful and important but nondomesticated species. Even in the absence of scientific criteria for selecting appropriate germplam accessions and assembling appropriate experimental genetic stocks, germplasm and genetic stock curators must constantly make critical decisions upon which entries are to be conserved on a constant bask. This discussion provided a framework for assigning some priorities. Major M. Goodman is currently William Neal Reynolds Dktinguished Univenity Professor of Crop Science, Statistics, Genetics, and Botany at North Carolina State University in Raleigh, North Carolina and a member of the US National Academy of Sciences. Dr. Goodman, a native of Johnston, Iowa, received his B.S. in Mathematics from Iowa State University and his M.S. and Ph.D. from North Carolina State University. After an NSF Postdoctoral at the Institute of Genetics, University of Sao Paulo, Piracicaba, S.P., Brazil, he joined the faculty of North Carolina State University in 1967. The initial t h m t of his research was upon the application of multivariate statistics to the classijication of the races of maize, including the use of isozyme allele frequencies. More recently, he has been involved in the rescue of maize genetic resources as director of a program to regenerate the national maize accessions held by Mexico, Colombia, and PenS, to store seed for backup of these accessions at the National Seed Storage Laboratory at Fort Collins, Colorado, and toplace adequate samples for distribution at the Regional Plant Introduction Station at Ames, Iowa. In addition he has been involved in the evaluation of maize genetic resources and is attempting to develop a program for urilizing them on a practical basis in his present position in charge of the corn breeding program at North Carolina State University. GENETIC RESOURCES AT RISK: I appreciate the opportunity to address the possibilities of choosing appropriate collections for maintenance, especially considering the problems that we are faced with in maintaining these very large collections. Obviously progress from plant and animal breeding depends upon germplasm, and indirectly it also depends upon genetic stocks. There are some big differences between germplasm stocks and genetic stocks in terms of ditliculty and expense of maintenance and in the degree of demand for samples. Germplasm stocks, generally speaking, usually consist of farmer varieties, landrace accessions, and wild or weedy or feral relatives of economically important (or potentially important) plant and animal species. Germplasm stocks may be used in basic research, but their most frequent use is for applied research involving, at least conceptually, improved plant and animal lines, breeds, varieties, or hybrids. Progress from breeding, genetics, physiology, and biochemistry depends to a great deal upon basic research conducted using our genetic stocks. These are mutant stocks, translocation and inversion stocks, various marker stocks, linkage tester stocks, etc. The two sets of stocks (germplasm and genetic) have to be handled very differently and represent very different sorts of problems and very different sorts of potentials, but they are both extremely important. But ultimately, in either case, future forms of these stocks depend on available genetic variations. Germplasm stocks of most of our major agricultural and horticultural crops are being used for both breeding and basic experimental work. Table 1 lists the currently most utilized germplasm collections, while Table 2 lists the most important genetic stock collections. Animal germplasm collections are much less centralized than plant collections, but exotic (imported) landrace stocks of cattle and swine are making important contributions to breeding programs. Major animal species are not generally used to establish genetic stocks (such as markers and mutations) in the way that maize and tomato have been. Mice and Drosophila serve as substitutes. Table 1. Germplasm Coffee Maize Potato Sugar Cane CoUections Being Used Conifers Millet Rice Tobacco Extensively for Breeding Cotton Oat Sorghum Tomato andfor Experimental Work Fruits/Nuts Peanut Soybean Wheat The use of the germplasm stocks listed in Table 1 varies greatly over time, depending upon the demands imposed by various disease and insect epidemics. Wheat has traditionally suffered periodic epidemics of both diseases and insects; thus, wheat germplasm stocks have been widely used for breeding. In contrast, maize germplasm stocks tend to be used as much for basic research as they are for applied research; maize has had many fewer widespread epidemics than wheat. SCIENTIFIC ISSUES, TECHNOLOGIES, AND FUNDING POLICIES The uses of rice, potato, tomato, soybean, and sorghum germplasm for applied research is also extensive. For tomato and potato, use has even been made of wild relatives in breeding work, a practice that is extremely rare virtually non-existent with maize's relatives (teosinte and tripsacum). In the past, humankind depended on an estimated threeto fivethousand species of plants. That has a message to us because today we are using only several hundred species of plants. In fact, we are obtaining the most part of our caloric intake from roughly 15 species of plants. These include most importantly cereals, grain legumes, and potatoes. The future of humankind depends vitally on those particular stocks. Within a given species, as plant breeding has progressed, we have begun depending on fewer and fewer cultivars. I can speak with authority on only one crop, and that is maize. In the New World there are something like 300 races of maize. But, in fact, the maize of commerce represents only six of those 300 races, and the maize of commerce of the United States represents only one. We are relying on the use of a very narrow germplasm base in the United States and in the world. Within that one maize race used in the US there were, in the early 1900s, thousands if not ten thousands of open-pollinated varieties of maize distributed all over the US Corn Belt. Essentially farmers or regions had their own group of varieties used for specialized purposes. With the large-scale development of plant breeding in the early 1900s and the development of inbred lines for use in hybrids, only a few of those open-pollinated varieties were widely used in corn breeding programs. In particular, only two or three made very substantial contniutions to corn breeding. Many of our hybrids today are represented by crosses between lines derived from the open-pollinated variety Reid crossed with inbred lines derived from the open-pollinated variety Lancaster. It is virtually impossible to find a hybrid that lacks a parent from either Reid or Lancaster. There are about six inbred lines and their close relatives that are represented in a very high percentage of all US hybrids. I cannot give you an exact percentage because it is not documented, but it probably represents well in excess of 50% of the planted acreage. Most crops are not hybrid crops and they do not depend on inbred lines, but the general story is true of virtually every crop. We have a wide diversity of genetic variability among primitive cultivars and historic cultivars. We have a much lower degree of diversity among our recent and prospective cultivars. Basically we are increasing productivity at the cost of variability; this is true of virtually every crop. It is also true of all our domestic animals. Furthermore, most of our breeding work consists of crosses of elite lines by elite lines. When things turn desperate, we search our more primitive materials for a source of disease or insect resistance, and then go through a backGENETIC RESOURCES AT RISK: crossing scheme to backcross that insect or disease resistance into elite materials. For this purpose we badly need access to adequate germplasm collections, but this need does not really serve as sufficient motivation to broaden our germplasm banks. Disease and insects show no signs of ceasing to evolve around cleverly designed defense mechanisms, whether they be plant resistance imposed by traditional breeding or pesticides engineered by Du Pont or Monsanto. While molecular genetics may temporarily change this, plant and animal breeders, who, after all, have practiced genetic engineering for a century now, recognize that most resistance is temporary. As a result, germplasm stocks in demand today are likely to remain in demand tomorrow. There are a number of germplasm collections which are widely used. Dr. Rick is going to speak to you next, I believe, about the extremely important collections of tomato that he maintains. In fact, tomato is one of our pleasanter stories in germplasm collection, maintenance, evaluation, and utilization. In addition, potato has an interesting story behind it. Those collections have been very well maintained, but for many other crops the status of germplasm accessions is much less pleasant a story. Answering the question of which germplasm stocks are important to maintain is reasonably easy. We can quickly answer which ones . critical germplasm are critical: most of those in Table 1. What we cannot do as easily is respond to the problem of which accessions and which geographic areas need sampling and how many accessions are actually needed. For that, more scientific information is needed than we often have available. That a choice must be made is reasonably obvious, and I would like to use an example, again from maize. A maize breeder in a given year can adequately maintain about 30 c