Shull, George Harrison, 1874-1954

George Harrison Shull (1874-1954) grew up on a farm in Clark County, Ohio. He graduated from Antioch in 1903 and went on to graduate school at the University of Chicago. He was appointed Botanical Assistant at the United States National Herbarium. He also worked at the U.S. Bureau of Plant Industry as a Botanical Expert examining the flora and fauna of the Chesapeake Bay and Currituck Sound. He used what he collected for his PhD thesis. He then became interested in the statistical analysis of variations of plants. In 1904, he was appointed in charge of the plant work at the Station of Experimental Evolution. Later he went on to Cold Spring Harbor. He studied and bred a large variety of plants and published papers of his findings of plant traits and inheritance. In 1915, Shull became a professor at Princeton University, and later became the managing editor of the school journal, Genetics, for ten years. Shull retired in 1942.

George Harrison Shull was a botanist. He was a botanical investigator at the Carnegie Institution of Washington from 1904 to 1915 and taught botany and genetics at Princeton University from 1915 to 1942.

George Harrison Shull was a botanist. He was a botanical investigator at the Carnegie Institution of Washington from 1904 to 1915 and taught botany and genetics at Princeton University from 1915 to 1942.

G. H. Shull worked on hereditary variation in many different plants during his career: the evening primrose ( Oenothera ), the shepherd's purse ( Bursa ), Indian corn ( Zea ), bean ( Phaseolus ), pink ( Lychnis ), foxglove ( Digitalis ), sunflower ( Helianthus ), tomato ( Lycopelricon ), poppy ( Papaver ), potato ( Solanum ), and tobacco ( Nicotiana ). He is chiefly noted, however, for one major achievement that laid the foundation for the development of hybrid corn and the other hybrids responsible in the latter part of the twentieth century for the "Green Revolution." This was probably the single most important agricultural advance of the century. It has been estimated that during World War II, when hybrid corn was first cultivated, it increased corn yields in the United States by 20 per cent -- a gain of 1.8 billion bushels worth $2 billion dollars, enough to pay for the Manhattan Project, and also enabling the United States to ship vast quantities of food abroad after the war, and so to prevent famine and pestilence.

Although many others were involved in the development of hybrid corn, Shull's contribution was the basic one. In breeding begun in 1905 at Cold Spring Harbor, he applied the principles of Mendelian heredity to analyze the inheritance of quantitative characters in corn (maize), especially the number of rows of kernels per ear. He self-pollinated the corn in order to produce a number of pure, inbred lines that differed in the average number of rows. These lines, as inbreeding continued, declined in vigor and productivity. When, however, they were crossed, the hybrids were not only extremely uniform but also highly vigorous and productive. They were definitely superior to the original open-pollinated strains with which Shull had started his work. Shull's papers of 1908 and 1909 describing this series of experiments in detail laid the basis for hybrid corn breeding with its higher yields, greater uniformity, more exact specializations to fit particular climates and soils, and desirable chemical content and nutritive qualities. Paul C. Mangelsdorf has said: "Certainly it was one of the most remarkable achievements of our time in the field of applied biology. Shull's idea of producing and maintaining otherwise useless inbred strains of maize solely for the purpose of utilizing the increased vigor and uniformity resulting from their hybridization was revolutionary as a method of corn breeding. It is still the basic principle which underlies almost the entire hybrid corn enterprise." In December, 1905, the Carnegie Institution of Washington selected G. H. Shull as the geneticist to work with the famed plant breeder Luther Burbank, to whom the Carnegie Institution had made a handsome grant of funds, in order to prepare "a scientific account of the ways, means, methods, and results of Mr. Burbank's work... " (President Woodward's first annual report, in the Yearbook of 1905). Shull was to begin in March, 1906, was to return to Cold Spring Harbor to carry on his own work from June through September, and then return to Santa Rosa to collaborate with Luther Burbank as long as necessary.

In July of 1906 Shull made a preliminary report to the Carnegie Institution of Washington. The unpublished manuscript of this report, a remarkably perceptive document commenting fully on Burbank's methods and results, and expressing also the great difficulties experienced by the young geneticist in trying to work with the opinionated elder plant breeder, remained unpublished in the Shull Papers, until unearthed and published by Bentley Glass ( Proceedings of the American Philosophical Society, 124: 133-153. 1980). As the sequel showed, nothing much ever came of the project, although Shull spent a number of additional months at Santa Rosa in the effort to complete his work. It dragged on until 1914, when Shull finally used the outbreak of World War I as an excuse to terminate the project. The Shull Papers, in addition to the manuscript of the 1906 report, contain newspaper and magazine clippings and handwritten notes by Shull, arranged genus by genus, all relating to Burbank's extensive collections of wild species and varieties of plants and his hybridizations.

Albert Francis Blakeslee, a geneticist and botanist, served as the director of Smith College Genetics Experiment Station from 1943-1954.

Albert Blakeslee's boyhood was spent in East Greenwich, Connecticut, where he early exhibited a strong liking for natural history. This leaning was not encouraged by his pragmatic father, who wanted the boy's education to plan for a financially independent career; but his mother was more sympathetic. After the two years of teaching at Montpelier Academy in Vermont, his natural inclinations were not to be denied, and he entered graduate study at Harvard with a determination to become a botanist. His Harvard professors, Farlow and Thaxter, greatly helped Blakeslee's development as a botanist. He engaged in a classification of the Mucors and discovered the positive and (sexual) zygospores and observed their sexual fusion to start the diploid phase of the Mucor life cycle. His summer in Venezuela as a plant collector for the Harvard Cryptogamic Herbarium (1903) and his two summers of teaching nature study in the Cold Spring Harbor courses broadened his knowledge of plants and generated in him a deep love of teaching. Thus, when he went to Germany for a postdoctoral fellowship in 1904, he was already becoming well known as a botanist.

At the University of Halle he worked under the distinguished mycologist Klebs for two years, with some stay during the period at the Universities of Berlin, Leipzig, and Oxford. This fellowship was supported by the Carnegie Institution of Washington. Blakeslee became fluent in the German language, as became apparent in later years when such a distinguished authority as Erwin Baur, plant geneticist, sent to Blakeslee in preference to any other English-speaking biologist a copy of his proposed publication on the dysgenic effects upon German life and culture of the post-war occupation of Germany's Rhineland by the French. Baur requested Blakeslee to be so good as to translate the communication into good English, edit it, and submit it for him to some American journal, such as Eugenical Notes, edited by Davenport. The original manuscript by Baur, the translation and very extensive editing -- really a toning down -- by Blakeslee, and the subsequent letter of withdrawal of the communication by Baur are all in the Blakeslee Papers, an invaluable addition to our knowledge of the course of German eugenics in the period between the two World Wars (see B. Glass, "A Hidden Chapter of German eugenics between the two World Wars," Proceedings of the American Philosophical Society 125: 357-367, 1981). While in Germany Blakeslee spent much time in art museums and attendance at concerts, and formed cultural tastes that were a lifelong joy to him.

Upon returning from Germany, Blakeslee accepted an appointment as professor of botany at the Connecticut Agricultural College, later to become the University of Connecticut. He taught many courses, in summer as well as during the regular year, and collaborated with C.D. Jervis in two popular handbooks for the identification of trees in New England and in winter. He made crosses of tree species, and successfully produced the first interspecific hybrid pine. His broad concern with social applications of botany and with teaching are to be seen in his paper presented in an American Association for the Advancement of Science symposium in 1909 on the subject, "The Botanic Garden as a Field Museum of Agriculture." He also conducted research on the genetics of poultry, and found certain genetic traits with visible effects that were linked with high egg yield; also he uncovered a negative correlation between yellow color and the time of a year when the last egg is laid. He discovered that Rudbeckia hirta, the black-eyed Susan, is a frequently mutating species. Beginning what was to become his most famous genetical work, that with the jimson weed, Datura stramonium, he worked out the simple Mendelian inheritance of white versus purple flower color and of spiny versus smooth seed capsules. In 1914-1915, he gave, at Storrs, the first college course in genetics in the United States. Also, while on leave and at the Cold Spring Harbor Laboratory as a research investigator, he resumed his early work on the Mucors; and in Datura found, in 1913, his first trisomic type, the "Globe" seedpod type, which has 2N + 1 chromosomes.

In 1915 Blakeslee was invited by C. B. Davenport, Director of the Carnegie Institution of Washington Station for Experimental Evolution at Cold Spring Harbor, to fill the place just vacated by George Harrison Shull, who was transferring to Princeton University. Blakeslee accepted, although he much regretted the loss of his opportunities to teach. He remained at Cold Spring Harbor until he retired in 1941, at the age of 67. He became greatly renowned for his work on Datura stramonium, in which he eventually found a trisomic type for every one of the twelve chromosome pairs in the species, each type recognizable by a distinctive phenotype of the seed capsule. With his assistants, he raised as many as 70,000 Datura plants in each summer. In 1920, he was joined by John Belling, a gifted cytologist, as his collaborator. They developed the skilled art of making acetocarmine stains of smeared plant chromosomes, a technique that became universally adopted as an enormous time-saver and also one productive of better microscopic differentiation of the chromosomes in the set. The typical chromosome numbers for many species of flowering plants were determined by the team.

In 1924, Dorothy Bergner replaced John Belling as Blakeslee's principal coworker. With Bergner, Blakeslee discovered a thirteenth trisomic in Datura. As there are only 12 chromosome pairs, a different explanation was sought, and found. There are also secondary trisomics, in which one arm of a primary chromosome has been doubled while its other arm is missing. Such a chromosome, added to the 12 types in which an entire chromosome is extra, greatly increases the diversity of chromosomal types. In search of the origin of these secondaries, numerous translocation types were found, types in which parts of two primary chromosomes had undergone a reciprocal interchange. In the pairing of homologous chromosomes that takes place during meiosis, these aberrations give rise to rings of four associated chromosomes, two normal plus two translocation chromosomes in the ring. Non-disjunction is a frequent consequence, and additional types of trisomics result. The discovery in natural populations of so much chromosomal diversity was a stepping-stone to the new evolutionary synthesis of the 1930s. Polyploid and triploid Daturas were also found, as populations from various parts of the world were analyzed. In 1937 it was discovered that colchicine will paralyze mitotic cell division and give rise to cells in which the chromosome number has been doubled. Using this technique, Blakeslee and Bergner produced polyploids, periclinal chimeras; and a new research assistant, Sophie Satina, collaborated in working out cell lineages during plant development.

Other collaborations, going back many years, were with E.W. Sinnott on quantitative inheritance, with I.T. Buchholz on pollen tube growth, with C.S. Gager on the use of radium to produce mutations. By means of exposures to radium or X-rays, 541 different gene loci were identified by mutation, 81 of which were mapped to a specific chromosome. It was also found that there was an increase of mutations during the storage of seeds. With I. van Overbeek, Blakeslee applied the techniques of tissue culture to the study of Datura genetic types.

In 1931, Blakeslee became deeply interested in the human inheritance of taste sensitivity to a chemical substance, PTC (phenylthiocarbamide). It is intensely bitter to most persons, but tasteless to others. Blakeslee checked this capacity in identical twins and found they were always similar in their capacity to taste PTC, or inability to taste it. He gave many popular lectures and demonstrations of this novel aspect of human heredity.

Blakeslee became involved in the administration of the Cold Spring Harbor Laboratory as early as 1923, and moved to greater and greater responsibility as Davenport aged. Upon Davenport's retirement in 1936, Blakeslee was the natural choice to succeed him. By this time he was one of America's foremost geneticists. He had helped to reorganize the American Journal of Botany in 1935, had been elected to the National Academy of Sciences and to the American Philosophical Society, and had been honored by many foreign scientific and learned organizations.

Upon retiring at Cold Spring Harbor, Blakeslee spent two years as a research associate at Columbia University, but found in 1942 an ideal situation for his "retirement" years in an appointment as a visiting professor at Smith College. Here he started up a four-college conference (Smith College, Amherst College, Mount Holyoke College, and Massachusetts State College -- later the University of Massachusetts) on Genetics, and a second on Human Relations. He initiated an active program of genetics at Smith College. With Miss Satina, he continued research on Datura by utilizing the technique of raising plant embryos in cell culture, in order to determine at what stage of development particular abnormal types led to deviations from normality, and just what they were. He became president of the Smith College Faculty Club, and worked to improve the conditions of retired faculty members. He spent much effort on human relations of the town-gown sort. As in previous periods of his life, he attended many foreign scientific congresses, for example, all of the Botanical Congresses (until 1950), and the Indian Scientific Congress in 1947. He was a visiting lecturer at Harvard University in 1948-1949. Upon his death, he left his estate to the National Academy of Sciences as trustee to provide continued assistance in maintaining and further developing a balanced genetics research program at Smith College. His personality was marked by great versatility, good humor, and a live social conscience. He was generous in giving credit to others in joint activities, yet in general somewhat reticent. These traits are reflected in some of his correspondence.