Wilhelm Rudorf was born on June 30, 1891 in Rotingdorf, district Halle in the province of Westfalia, Germany, where his father was a practising farmer, and died 26 March 1969.

He visited the elementary and a private secondary school in Werther, 1898-1907, and for the last four years in Bielefeld, where he passed his qualifying examination (Abitur) in 1913. He started academic studies in Romance philology at the universities of Göttingen and Münster/Westfalia, which, however, were interrupted by the onset of World War I in 1914. He did service as soldier all four years and was discharged from prison of war in 1919. He then took up university education at the Agricultural College of Berlin in 1920 and graduated with a diploma in agricultural sciences in 1923.

After move to the University of Halle/Saale he was recruited by Prof. Theodor Roemer as candidate for a doctor’s degree and finished his thesis in 1926 with “Statistical analyses of variation in varieties and lines of oats”. For 1927-1929 he became an assistant of the directing manager of the large agricultural estates of Wentzel in Teutschenthal and Salzmünde and concluded this period with an inaugural dissertation (Habilitation) at the Halle university in the field of agronomy and plant breeding entitled “Contribution to breeding for immunity against Puccinia glumarum tritici (stripe rust of wheat)”.

In 1929 Rudorf was invited for professorship at the University of La Plata in Argentina. Here he founded and established the Instituto Fitotécnico in Santa Catalina and served as its director until 1933. Although the worldwide economic crisis precociously terminated his stay and these activities, Rudorf successfully paved the way for an essential progress in rust resistance, which rescued the wheat production of this country from collapse through the annual disaster of stripe rust epidemics.

After a three years’ period as an ordinary professor and director of the Institute of Agronomy and Plant Breeding at the University of Leipzig, Rudorf was appointed director of the Kaiser-Wilhelm-Institute of Breeding Research in Müncheberg/Mark following the late Erwin Baur. At the same time he became professor for breeding research at the University of Berlin. In 1945 the Kaiser-Wilhelm-Institute was transferred to Western Germany and found an almost ten years’ interim shelter at a state property in Voldagsen near Hameln. Only in 1955 was the new homestead prepared for the now Max-Planck-Institute for Breeding Research in Köln-Vogelsang, and the move into modern laboratories and glasshouses, to appropriate experimental fields and administrative buildings finally set the new stage for modern scientific developments. Rudorf retired 1961 with 70 years of age concluding a remarkable achievement of life. He had guided this renowned scientific institution far-sighted and secure over three locations at economically and politically more than difficult times. He had been able to keep its broad palette of scientific subjects as well as its numerous scientists and working stations stimulated and active. In all, this not only required immense administrative skills and the full toughness of his Westfalian character but also much personal sympathetic understanding. Again and again he assembled old and new experts to fruitful cooperation, and he provided working conditions, in which successful breeding research could develop to international recognition.

Rudorf actively intervened with personal scientific contributions in many fields of his Institute’s research programme. His particular interest continued to be directed towards plant pathogen resistance, and he extensively applied wide crosses with related species and even genera to achieve progress in wheat resistance. After the death of G. Stelzner in the last days of World War II, he took over the charge of direction of the Potato Division of the Institute and engaged himself actively in experimental work not only for Phytophthora- and virus- but also for beetle-resistance. Thanks to such active support and the long successful work of his coworkers Mrs. Becker and Baerecke as well as Prof. Ross and Mag. Frandsen it finally happened that almost a quarter of all seed potato fields in Germany were planted with varieties, which directly or indirectly were derived from work in the Institute in Cologne. With own experiments Rudorf also participated in breeding for combined Gloeosporium- and virus-resistance of Phaseolus-beans. He conducted extensive investigations with medicinal plants, such as Datura, Digitalis and Mentha, on the effects of polyploidization, and he described after experimental mutagenesis mutants with potential breeding value, e.g. compactum-forms of Festuca pratensis, unifoliata-mutants of Medicago sativa or leafy, finely branched types of Melilotus albus. He attained practical success particularly with breeding of forage and oilplant species: He developed a lime-tolerant alfalfa, a highly vigorous and productive white clover and the low-coumarin melilot variety ‘Acumar’. He created synthetic rapeseed from interspecific crosses of turnip x cabbage and gained considerable progress with soybean in combining earliness, yield and other important traits of performance. In all such instances he made use of his long experience with problems in physiology of crop development and the genetics of developmental traits. Last not least was Rudorf one of the first in Germany to recognize the crucial importance of heterosis in breeding for yield characters, and he effectively supported hybrid breeding in maize by elaborating efficient breeding designs. Indeed, Rudorf’s life work represents genuine applied science, never loosing sight to the improvement of cultivable varieties nor to the involved basic scientific questions.

Rudorf devoted himself to many public duties and cooperations within the German Agricultural Society (DLG) and the Federal Association of Plant Breeders (BDP). He founded the most successful German study group on potato breeding and seed potato production and continued at his Cologne Institute the seminars for practical plant breeders initiated by his predecessor Erwin Baur. He set out in 1958 for a several months’ lecture and study trip through North- and South-America and lectured as honorary professor at the University of Göttingen (1946-1955) and the University of Cologne (1956-1961) thereby supervising 13 Ph.D. theses. Together with Theodor Roemer he edited the 5 resp. 6 volumes of the Handbook of Plant Breeding, published by Paul Parey, Berlin (1st edition in 1941-1950; 2nd edition in 1958-1962) also contributing many own articles to this reputed monograph. He published more than 120 original papers in high ranked international journals.

The merits of Rudorf were recognized by honorary memberships of the Finnish Scientific Society for Agriculture, the Swedish Utsädesförening, the Sociedad Argentina de Agronomia and the Zool.-botan. Society of Vienna. He became Consejero de Honor Superior des Investigaciones Scientificas Madrid and from 1959-1962 president and then honorary president of EUCARPIA.

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by G. Röbbelen, Institut für Pflanzenbau und Pflanzenzüchtung, Georg-August-Universität Göttingen, Von-Siebold-Str. 8, D-37075 Göttingen / Germany