He was born in 1924. His father was a builder in Oldham, Lancashire, and he probably would never have gone to university had he not been able to take advantage of the Ex-Serviceman's Scheme after serving as an infantry officer in the Second World War. Riley enlisted in 1942 and, after being injured in Germany in 1945, he spent 18 months in Palestine dealing with unrest at the end of the Mandate.
He entered Sheffield University in 1947 and, after his undergraduate degree in Botany, studied for a PhD with John Thoday who whetted the young Ralph's interest in genetics. He was only two years into his PhD when he was recruited by Douglas Bell, then the Director of the Plant Breeding Institute at Cambridge, to study the introduction of useful variation into the wheat crop from its wild relatives, and to take wheat breeding on to the next step. Two years later in 1954 Riley became the founder and first Head of the Cytogenetics Department at the PBI.
Although Riley's was a very fundamental approach to wheat genetics he never lost sight of the goals of plant breeding, which was at that time a fairly empirical science. His initial aim was to widen the gene pool by making the variation in wild relatives available to wheat breeders. In 1957, he discovered the method of doing so by finding the Ph gene which controlled pairing between the chromosomes of wheat and wild relatives of wheat. Soon he was able to devise and demonstrate the cytogenetic ways by which useful genes, such as those that confer novel disease resistances, could be transferred into wheat from a host of wild species.
This discovery of the Ph gene allowed the first "genetic engineering" and his methods have since been used around the world in all major cereal breeding programmes. Many of these applications have produced varieties for use in developing country agricultures, which was also one of Riley's motivating forces. His election to the Royal Society in 1967 and a range of prizes, including the Wolf Foundation Prize in Agriculture in 1986, reflect the importance of the discovery.
In 1972, against his initial inclination, he took the post of Director of the PBI, where he commanded respect for his scientific leadership as well as his achievements in research. His six years as Director were characterised by a drive to improve production in UK arable agriculture, the development of fundamental research programmes in an environment where the discoveries could rapidly be brought to bear on breeding, and the beginning of plant molecular biology in the UK. In short Riley ensured that the PBI was a model for the application of science to plant breeding.
During his directorship wheat yields increased from four tonnes per hectare to 6 t/ha, due in large part to the improved PBI varieties which covered 75 per cent of the crop area of the UK. These increases continued till the record year of 1984 that saw 8.4 t/ha. Output increases were even more impressive rising from 4.8 megatonnes to 13.8 Mt. This was particularly vital at a time when the UK needed to be less reliant on North American imports.
Riley had foreseen the importance of molecular biology and, by skilful lobbying, obtained significant funds to start the first plant molecular biology initiative in the UK. The UK's present position in this key area of plant science is very much due to this beginning in Trumpington in the mid-1970s. His six years in the post saw remarkable advances and were probably the heyday of this world-famous institute that continued until privatisation in 1987. Riley was, of course, depressed to see the mix of fundamental and applied science that he had built destroyed when the PBI was privatised, shortly after his retirement.
In 1978 Ralph Riley left a much- expanded PBI to become Secretary (chief executive) of the Agriculture and Food Research Council (now the Biotechnology and Biological Sciences Research Council). As Secretary, under a very difficult financial regime, he provided yet further stimulus for the development of biotechnology in UK universities and institutes. Although Riley oversaw the closure of several institutes, he was adamant that traditional research with the potential to bring new understanding or to lead to new technologies was retained. He was knighted for his services to science in 1984.
After his official retirement from UK agricultural research Riley had more time to devote to overseas agricultures. Although he considered it unwise precipitously to include the new science in the programmes of the international agricultural research institutes, he considered it his duty to ensure that the institutes were aware of the opportunities on offer. While pursuing this aim, Riley sat on the board of trustees of the International Rice Research Institute in the Philippines. In 1993, after a period on the board of the International Center for Agricultural Research in Dry Areas, he became a member of the Technical Advisory Committee to the Consultative Group on International Research, where he could have most impact. He also became Chairman of the Scientific Advisory Committee for the remarkably successful Rockefeller Foundation's Rice Biotechnology Program.
His interest in development was also exemplified by his leading a Food and Agriculture Organisation/UN Development Programme team to increase grain production in Bangladesh in 1989. His great interest in international agriculture continued undiminished until his death.
All of us whose lives and research have been influenced by Ralph Riley will remember a research leader and manager who had time to talk. His question was always "What's new?" He helped with careers by knowing when and how to get to the right people at the right time. He was also a fighter on his own behalf. He was dogged by ill-health and eye problems arising from diabetes for much of his life, but worked prodigiously regardless.
Ralph Riley, plant geneticist: born Scarborough, Yorkshire 23 October 1924; research worker, Plant Breeding Institute, Cambridge 1952-78, Head of Cytogenetics Department 1954-72, Director 1971-78; FRS 1967; Fellow of Wolfson College, Cambridge 1967-92 (Emeritus); Special Professor of Botany, Nottingham University 1970-78; Secretary, Agriculture and Food Research Council 1978-85, Deputy Chairman 1983-85; Kt 1984; married 1949 Joan Norrington (two daughters); died Cambridge 27 August 1999.