Alumni Memories

Essays on the College of Agriculture's History

Cooperative Federal-State Corn-breeding Program

By Arnel R. Hallauer

Arnel. R. Hallauer

The cooperative federal-state corn-breeding program at Iowa State started in the spring of 1922 when M. T. Jenkins was transferred to Ames from Wisconsin. He was very successful in developing inbred lines for use in double-cross hybrids and technology for developing and testing double-cross hybrids. Jenkins remained at ISU until 1934 when he transferred to Beltsville, Md. He was succeeded by A. A. Bryan who led the program from 1934 until his death in 1939. G. F. Sprague succeeded A. A. Bryan and was leader of the corn-breeding program until his transfer to Beltsville, Md. Similar to Jenkins, Sprague was very effective in developing germplasm (e.g., Iowa Stiff Stalk Synthetic) and procedures for developing inbred lines for use in double-cross hybrids.

I joined the cooperative federal-state corn-breeding program as a graduate student in 1956. Professor Sprague was my major adviser for my master’s degree. He transferred to Beltsville, Md. in 1958 to become investigations leader, ARS/USDA of the corn and sorghum research programs in the United States. I was selected to replace Sprague with the corn-breeding program that same year as a full-time employee with the ARS/USDA. I was with the program as a full-time employee from 1958 until my retirement in 2003. I served as an ARS/USDA employee from 1958 until 1989 and an Iowa State employee 1990 until 2003. During my employment I fulfilled requirements for my doctorate in 1960 with W. A. Russell as my major adviser.

During my tenure with the cooperative federal-state corn-breeding program, many changes occurred within the hybrid seed corn industry. Although significant changes occurred in the types of research conducted and the technologies available to conduct research, the main goals of the Iowa State corn-breeding program have remained the same:

Basic research studies with long-term goals of genetic enhancement of germplasm resources;
Education and training of graduate students with majors in plant breeding; and
Applied research to evaluate lines and hybrids developed from our germplasm enhancement research. Based on numbers of experimental plots conducted each year, approximately 80 to 85 percent of our resources were allocated to basic research, including graduate student thesis research (goals 1 and 2) and 15 to 20 percent of our resources were allocated to the testing of inbred lines and hybrids (goal 3).

I was one member (there were always three to five staff members) of the cooperative federal-state corn-breeding program for 45 years, interacting with all phases of the basic and applied research. My research emphasis included:

The study of the inheritance of quantitative traits of corn population and hybrids to determine the relative importance of different types of genetic effects, their inheritance and levels of dominance of genes affecting heterosis;
Conducting long-term recurrent selection studies to determine their relative response to selection with use of different types of progenies (S1, S2, half-sib and full-sib) to determine response of selection among progenies;
Introduction, adaptation and evaluation of tropical germplasm to determine their potential to expand the germplasm base of U.S. corn breeding programs; and
Introduction and transfer of improved protein quality germplasm (QPM) from tropical and semi-tropical lines to inbred lines adapted to the U.S. Corn Belt.

The results from my basic research program have been reported in more than 200 research reports in refereed journals, summarized in the book “Quantitative Genetics in Maize Breeding” by me and J. B. Miranda published by ISU Press (468 pages), and published in 88 graduate student master’s and doctorate theses. Collectively, about 200 graduate students have completed their master’s and doctorate degrees in corn breeding since Sprague.

Major research conclusions are: additive genetic effects of greater importance in corn populations with partial to complete dominance of favorable alleles; it was not possible to quantify the relative importance of epistatic effects; heterosis in corn hybrids is due to complex interactions of alleles at each locus (dominance) and among loci (epistatis); response to recurrent selection was realized in all instances; response to inbred progeny selection seemed to plateau after three to four cycles of selection but response to full-sib recurrent selection continues after 16 cycles of selection; elite tropical populations (ETO, Tuxpeno, Antigua, Suwan-1, and Tuson) were adapted to U.S. Corn Belt environments after six to eight years of intense selection for earlier flowering plants; BS28 (adapted Tuxpeno from Mexico) and BS29 (adapted Suwan-1 from Thailand) are currently under reciprocal recurrent selection in Iowa; conversion of tropical high protein line sources to U.S. Corn Belt conditions in final stages of evaluation for agronomic and chemical traits; and I have been editor of two editions of the book “Specialty Corns” published by the CRC Press. Although applied research was only 15 to 20 percent of our total research program, the applied aspects of the cooperative federal-state corn-breeding program have made significant contributions to the hybrid seed corn industry.

During the period from 1958 to 2003, inbred lines B37 through B121 have been released for use by public and private corn-breeders. Inbred lines B37, B57, B59, B64, B68, B73, B77, B84, B94, and B97 have been prominent in pedigrees of hybrids. Based on surveys by the American Seed Trade Association B37 appeared in pedigrees in about 25 percent of the commercial hybrids seed produced in the early 1960s. Similarly, B73 was a popular inbred being used in about 22 percent of the total hybrid seed produced in the 1970s.

A recent article in Crop Science (May-June issue, 2006) showed that of the plant patents and PVPs issued for corn inbreds by the early 1980s that 63 percent of the inbred lines included some Iowa Stiff Stalk Synthetic germplasm in their parentage. In addition to the direct use of the Iowa “B” lines as parents of hybrids, the Iowa “B” lines were subsequently used in breeding programs to develop recycled lines. Records show that there are more than 30 recoveries of B37, more than 70 recoveries of B14, and more than 110 recoveries of B73. The current heterotic groups recognized by the U.S. Corn Belt corn-breeders are designated as Iowa Stiff Stalk Synthetic and non-Iowa Stiff Stalk Synthetic.

Because of the continuous selection and breeding methods used by the cooperative federal-state corn-breeding programs since 1958 the development of inbred lines important to the commercial seed industry has demonstrated the important “B” lines also are used throughout the world in important temperate areas where hybrids are produced and used.

Colleagues in biological sciences have recognized our efforts and contributions. G. F. Sprague and I were elected as members of the National Academy of Sciences in 1970 and 1988, respectively; and I was inducted in the USDA Hall of Fame in 1992. I and other staff members have been recognized by our peers as fellows of Crop Science Society of America, including Sprague, Russell, S. A. Eberhart and K. R. Lamkey. And Sprague and Eberhart were elected as presidents of the Society. They have also been recognized by other national and international awards. The Arnel R. Hallauer International Plant Breeding Symposium was held in Mexico City, Mexico in 2003.