Martin L. Carson
Marty Carson was born in Mowequa, IL, and grew up in the small farming community of Arcola, IL. He received a B.S. degree in botany from Eastern Illinois University and M.S. and Ph.D. degrees in plant pathology from the University of Illinois under the direction of Arthur L. Hooker. He began his career in 1980 as a faculty member in the Plant Science Department at South Dakota State University (SDSU), Brookings. After 8 years at SDSU and with a brief stint in private industry, he joined the USDA-ARS in Raleigh, NC, in 1989. In 2002, Carson became research leader and director of the USDA Cereal Disease Laboratory, St. Paul, MN.
Carson’s nationally and internationally recognized research focuses on the genetics of resistance to disease with emphasis on quantitative, partial forms of resistance. He has been a leader in applying quantitative genetic theory and methods to the study of host-pathogen interactions and breeding for host resistance. Carson developed a method for evaluating how different models of gene-for-gene interaction apply to pathosystems in which the host and pathogen exhibit quantitative variation for resistance and aggressiveness, respectively. The widely accepted idea that significant cultivar by isolate interactions always indicate gene-for-gene interaction was shown to be incorrect. Extending quantitative genetic theory to the plant breeding problem of simultaneous selection for yield potential and disease resistance, Carson developed, proposed, and demonstrated the efficacy of an alternative method for the efficient improvement of yield and disease resistance simultaneously. Instead of relying on some form of complex index selection, plant breeders could simply select genotypes that yield well under disease stress.
Carson has extensive accomplishments in applied research on a diverse array of maize diseases. He showed that extended latent period length is the major component of partial resistance to northern leaf blight, a devastating disease of maize throughout the world. He demonstrated that increased latent period length can be conclusively measured on seedling plants prior to anthesis and may even be assessed under greenhouse conditions in the off-season, allowing breeders to more efficiently select for partial resistance to northern leaf blight. His research on the sources and inheritance of resistance to anthracnose diseases of maize allowed the hybrid seed industry to rapidly develop commercial proprietary inbred lines with high levels of resistance. A highly resistant inbred line identified in these studies, MP305, has been used extensively by the seed industry as a source of resistance to anthracnose stalk rot. Carson reported the first occurrence in the continental United States of Phaeosphaeria leaf spot of corn. He identified sources of resistance to the disease in U.S. maize germplasm and demonstrated that several popular and widely used inbred lines were susceptible to the disease. The inheritance and the location of quantitative trait loci controlling resistance to Phaeosphaeria leaf spot were determined in the inbred line Mo17. Carson developed a set of near-isogenic maize inbred lines that varied in reaction to Goss’ bacterial wilt. When tested in hybrid combination with a susceptible tester inbred, the relationship between disease severity and yield losses due to Goss’ wilt was established without the confounding effects of differing plant maturities or plant architecture. Following this study, three inbred lines with superior disease resistance and yield potential of the recurrent parent line were released. Further inheritance studies identified superior sources of resistance to Goss’ wilt in early-maturing inbred lines of maize that proved vital to the seed industry in the development of resistant, early-maturing hybrids for the northern cornbelt. Carson demonstrated that variation in aggressiveness among isolates and sibling species of Cercospora zeae-maydis is often the cause of genotype × environment interactions seen in maize gray leaf spot (GLS) trials and that there is no evidence of either species or isolate specificity in response to resistance of maize to GLS.
Carson was the first to demonstrate and quantify yield losses in sunflower due to several largely unstudied diseases. As a result, the potential importance of these diseases to sunflower production is now recognized, and a sound basis for setting priorities in sunflower research programs was established. It was clearly shown that the relatively new disease, Alternaria blight, caused by Alternaria helianthi was capable of causing substantial yield losses in sunflower, whereas foliar diseases caused by A. zinniae and Septoria helianthi were of minor importance. Carson also demonstrated the role of Phoma macdonaldii in the early-dying syndrome of sunflower and the potential resulting losses. The identification of these pathogens and the rapid dissemination of this information allowed plant breeders and others in the hybrid sunflower and corn industries to react to these potential new threats before widespread significant crop damage occurred.
Carson was instrumental in the successful establishment of the southern GEM (Germplasm Enhancement of Maize) project, serving as southern regional coordinator from 1995 to 2002. This project is a cooperative effort of public and private sector maize breeders, representing more than 20 seed companies, USDA-ARS, and university scientists. He was instrumental in developing protocols and policies governing the procedures used to introgress selected exotic germplasm into elite lines adapted to the U.S. cornbelt. Several germplasm lines, containing 50% tropical germplasm and having the yield potential of commercial check hybrids, have been released from the southern GEM project, including nine lines developed by Carson himself.
Carson has served The American Phytopathological Society in various capacities. He was associate editor of Plant Disease and as associate and senior editor of Phytopathology. He has served on the Genetics, Host Resistance, and the Germplasm and Collections Committees. Carson’s determination to make plant pathological research useful to solving problems and furthering the science of plant pathology is second only to his compassion for others. His concern and caring for his work and for the people with whom he works makes him a truly special person.