Irvine Armstrong Watson 1914-1986

Written by R.A. McIntosh and S. Smith-White.

Emeritus Professor Irvine Armstrong Watson, formerly Professor of Agricultural Botany and Dean of the Faculty of Agriculture in the University of Sydney, was born at Parkes, N.S.W. on 31 March 1914 and died on 1 March 1986. He was the fourth son of Wesley Watson, a well known and successful farmer in the district.

Family background and education

In a family of six children, Irvine Watson grew up on a wheat and sheep property near the village of Tichborne in the Parkes district. The family bonds were very strong and his father and brothers, who continued the farming tradition, were later to give him strong support in the development of his wheat breeding work.

Following local primary schooling, he was enrolled first at Walleroi College at Orange, where his enthusiasm for cricket and his pride in attaining selection for the school's First XI exceeded his scholastic ambitions. He then attended Hurlestone Agricultural High School at Glenfield, where his interest in an academic career really began, and he was dux of the school in 1932. He entered the Faculty of Agriculture at the University of Sydney in 1933. His progress was interrupted in November 1936 by illness which prevented him from taking his final examinations in December of that year, and delayed achievement of his degree for twelve months. Despite this, he graduated B.Sc.Agr. with first class honours in 1938. It is of interest that in December 1936 both the Dean of the Faculty, Professor R. D. Watt, and Dr (later Professor) W. L. Waterhouse wrote to his father indicating their appreciation of his work, his high likelihood of gaining first class honours, and their belief in his successful future academic career.

In May 1938, Watson was appointed Assistant Lecturer in the Faculty of Agriculture in the University of Sydney, with instructions to 'take over lectures at any time' from Dr W. L. Waterhouse. Shortly afterwards he was awarded the Thomas Lawrence Pawlett Scholarship by the University. In 1939 he proceeded to the U.S.A. and enrolled for Ph.D. studies at the University of Minnesota specialising in plant breeding and plant pathology. He took courses from H.K. Hayes and C.C. Christensen in plant breeding, from C.R. Burnham in genetics and from E.C. Stakman in plant pathology. His thesis project, leading to the award of a Ph.D. in 1941, included a study of rust resistance in certain Kenyan cultivars of wheat.

In a letter to the then Vice-Chancellor of the University of Sydney, Christensen made two significant statements about Irvine Watson, namely: 'Being an excellent speaker, a clear thinker, and possessing an ability to inspire and convince his listeners, he should be a first-rate teacher' and 'Dr Watson is courteous, pleasant to deal with, democratic, gets along well with many different types of people, and is a very good co-operator. We believe he is a natural leader and one who could probably serve as an administrator as well as an investigator.' These views were fully substantiated by Watson's subsequent achievements. Stakman wrote to Irvine's father in similar terms: 'Irvine is one of the very best students that we ever had in the Department of Plant Pathology at Minnesota. He did a very fine piece of research. He was one of the most popular men whom we have ever had.'

Academic career

In 1941, Watson resumed his position as Assistant Lecturer within the University of Sydney. He became Lecturer in 1944, was promoted to Senior Lecturer in 1946 and Associate Professor of Genetics and Plant Breeding in 1955. In 1962, with the establishment of separate departments within the Faculty of Agriculture, he became the inaugural Professor of Agricultural Botany (Plant Breeding) and he held this position until his retirement in 1977.

E. P. Baker, who had been a fellow undergraduate in the same class with Watson, and who later took a Ph.D. at the University of California, was appointed as an assistant to Dr Waterhouse in 1942, and as a lecturer in 1949. Watson and Baker shared their teaching loads, Baker giving courses in genetics and cytogenetics. Together they had a considerable impact in the area of plant breeding. Watson was versatile in his teaching, and in his early years gave courses in biometry and experimental design. He then taught genetics and plant breeding to students specialising in several aspects of agronomy at a time when few universities in the country were offering such courses. As a consequence, graduates in the area were sought after for positions in plant breeding, not only in New South Wales but also in other states and even outside Australia. Following the appointment of K.S. McWhirter in 1964, Watson's teaching load was reduced and he gave short specialist courses and taught host-pathogen genetics and breeding for disease resistance for students majoring in agricultural genetics and in plant pathology. His reduced teaching load after 1964 enabled him to devote more time to the service of the wheat industry through the development of research centres at Castle Hill and Narrabri, and permitted greater involvement on his part in state and national committees concerned with wheat.

Having a keen and discerning interest in plant pathology, Watson was closely involved with the promotion of N.H. White to a chair of plant pathology within his Department of Agricultural Botany and, following White's retirement, with the establishment of a separate Department of Plant Pathology and Agricultural Entomology. F.J.D. McDonald was appointed as entomologist in 1966, and B.J. Deverall became head of the new department in 1973. Professor Deverall has stated that Watson's personal character, his interest in disease resistance and parasite specialisation, and the resoures that he had built up at the Castle Hill Research Station, all led to his (Deverall's) acceptance of the new chair.

As a teacher and research leader, Irvine Watson maintained a genuine interest in the work and welfare of associates. This was especially true of his junior research staff and assistants by whom he was affectionately known as 'Prof.'.

Wheat breeding

It is difficult to outline the complex and wide-ranging role that Watson played in the wheat industry from 1938 to 1977. He acted directly in precipitating some developments and took advantage of timely situations permitting others to occur. His own rural background gave him an understanding of farming and of farmer assessments, and he had a perceptive awareness of the varietal needs of the wheat industry. He was an agriculturalist as well as an agricultural scientist, and was appreciated by both the farming community and his scientific peers. He enjoyed discussions with individual farmers and attendances at meetings of farmers' organisations. Equally, he enjoyed his association with wheat industry planning and funding organisations.

The Waterhouse-Watson association

Watson's early association with Waterhouse, and his active involvement with the field work that had been initiated by Waterhouse, undoubtedly influenced his general attitude to wheat breeding work, particularly in relation to the need for and the development of field stations. Waterhouse had already established wheat plots on the farms of two old friends, Mr. C.H. Beeson of Gunnedah and Dr E. Bligh of Brookstead, Queensland. However, he suffered a severe heart attack early in 1942 and was thereafter unable to engage in field work. Consequently, all such work became Watson's responsibility, with assistance from Baker. This responsibility also involved the work at the W.L. Waterhouse Wheat-breeding Station at Curlewis which had been established in 1945 with financial assistance from the Rural Bank. Watson continued these farmer associations and also received help in land, labour and intelligent interest from his father and brothers in the Parkes district. The important wheat cultivar Gabo (see below), properly credited to Waterhouse, owed a great deal to Watson and Baker for final field selection, development and increase. Later cultivars produced and released between 1945 and 1960 also depended on the Curlewis field station for the final stages of their development.

Another important connection initiated by Waterhouse was continued and developed by Watson. This was with the flour milling industry and particularly with Mr E.E. Bond who at first was the cereal chemist at Bruxton's Mill, Granville N.S.W. In the 1930s, the only quality assessment available to the University's wheat breeders was the Pelshenke test; all other quality evaluations capable of giving more reliable inforrnation, were made by staff of the various flour mills. With the creation of the Bread Research Institute in 1947 and Bond's appointment as director, the quality testing work was transferred to the B.R.I., and Eric Bond continued his close professional and personal contact with Irvine Watson and the University programme. There is no doubt that this close connection contributed immensely to the development of the current Australian prime-quality hard wheat industry.

W.L. Waterhouse spearheaded research on the cereal rusts in Australia and the development of rust resistant varieties. In the early 1930s the dominance of a new and virulent pathotype of the wheat stem rust fungus called race 34 by Waterhouse but later designated race 126 by Watson, emphasised the need for continuous wheat breeding work. The first new and successful wheat cultivar resistant to the dominant pathotype was Eureka, bred by S. L. Macindoe at the N.S.W. Department of Agriculture Experiment Farm at Glen Innes. It was extensively grown for a time, but by 1942 its resistance was breaking down, and it fell from favour. Waterhouse's cultivar Gabo, registered and released in 1945, derived its rust resistance from a durum wheat source. It had short straw and high yielding ability, and gave flour of excellent bread-making quality. It soon became widely grown and for a number of years was the leading wheat cultivar in Australia. It also had another significant but previously unrecognised character, namely day length insensitivity. It became an important donor of this character overseas, and contributed to the 'Green Revolution' that developed first in Mexico(1) and that benefitted many developing countries, especially India and Pakistan. Gabo and a sister selection, Timstein, released in the U.S.A., were used in the crossing programme that resulted in the Mexican cultivars Cajeme, Mayo and Nainari.

The release of Gabo, following the rusting of Eureka in 1942 and 1943, was an event of great significance in north-western New South Wales. It demonstrated that high-quality rust-resistant wheats could be grown in areas where wheat farming had previously been a high risk enterprise. Importantly, it boosted the morale of the farming community.

The later wheat cultivars

In addition to Gabo, the association of Waterhouse and Watson achieved the breeding and release of Kendee (1946), Saga (1951), and Koda (1955). Watson and E.M. Matheson were associated in the development in 1960 of Gamenya and Mengavi, the former being the more important. Then from Watson and N.F. Derera came Mendos (1965), Gamut (1965), Timgalen (1967), Gatcher (1969), Songlen (1975), Timson (1975) and Shortim (1977). After Watson's retirement in 1977, three additional varieties were produced from his hybrid breeding stock. These were Sunkota, Suneca and Sunstar, released in 1981, 1982 and 1983 respectively. Sunstar was of interest because the initial crossing programme that led to its development was designed to produce a feed wheat with a distinctively coloured purple grain. When this objective proved unacceptable to the wheat industry, white-seeded segregates with satisfactory bread-making characteristics were selected.

The importance of the new wheat varieties coming from the Watson team is unquestionable. Gamenya, at its peak, replaced Gabo as the most widely grown variety in Australia. University-bred varieties have at times made up one-third of all the wheat sown on the continent. Equally significant, no appreciable yield losses were experienced from 1956 to 1977 in areas where varieties carrying the 'Watson' label had found acceptance. Since 1977, due in no small measure to the continued production of new resistant varieties, stem rust has not presented a serious problem to wheat grown in this country.

Irvine Watson's ability to collaborate with other people, as a junior with Waterhouse or as a team leader with his other associates, is brought out by a perusal of his bibliography. His success in this direction as well as in his other activities confirmed the predictions of his early tutors.

Rust research

Following his graduate programme at the University of Minnesota, Watson developed interests in population and epidemiological aspects of cereal rust pathogens. He continued and expanded various aspects of the work initiated by Waterhouse. Whilst he maintained an interest in all cereal rusts as well as flax rust, his personal work concentrated on the stem rusts of wheat, rye and certain grass genera, and to a lesser extent on wheat leaf rust. His colleagues continued to work on the rusts of oats and barley.

The mechanisms of variability in rust pathogens

As already mentioned, a particular pathotype of the stem rust fungus was dominant in Australia and New Zealand in 1938, at the time of Watson's appointment to the staff of the University of Sydney. This pathotype, race 126, was not derived from the earlier races present in Australia, since it differed in respect of several genes conferring avirulence and virulence. It was first observed in Western Australia in November 1925(2) and spread rapidly to the eastern States and to New Zealand. It almost certainly arrived in Australia by distance dispersal, possibly from southern Africa. It was extremely aggressive and soon eliminated all rival pathogen races. The reason for and basis of this aggressiveness in race 126, and later in some other races, interested Watson from the beginning of his career. His graduate work had included competition studies wherein mixtures of pathotypes were inoculated on to hosts highly susceptible to all types used. These experiments demonstrated that some aggressive pathotypes could displace other less aggressive ones; there was a kind of peck order.

The resistance of Eureka (see above) to race 126 was due to a gene Sr6. Eureka became susceptible because a mutation occurred at a pathogenicity locus in the pathogen whereby an avirulence allele was converted to a different, or inactive, state. Gabo owed its resistance to a different gene, Sr11, and a different mutational event in the pathogen caused it to become rusted in 1948. Waterhouse and Watson were able to demonstrate that the new pathotypes were identical with the earlier predominant form except for their separate abilities to infect the previously resistant cultivars and other genotypes possessing the same genes. In 1957 Watson reported experiments in which he selected single step variants in the greenhouse. He attributed the pathogenic changes that he found to mutation. In the U.S.A., whilst on sabbatical leave, he repeated experiments demonstrating that new variants could arise from mixed infections with certain contrasting pathotypes and concluded that the mechanism involved was more complex than mutation or simple nuclear exchange in a dicaryon with two mating types. The phenomenon, later designated somatic hybridisation, was considered to be similar to that observed in Aspergillus and given the name parasexuality by Pontecorvo.(3)

Local variability, caused by mutation and somatic hybridisation, was apparently superimposed upon occasional introductions of inoculum from outside the Australasian region. One group of putative introductions, occurring in 1968 was examined in detail. The evidence indicated that the pathotypes involved had been wind-borne from the African continent, where identical pathotypes were known to occur. These introductions became established in Australia where they or their derivatives are now the predominant pathotypes. This introduction by distance dispersal contrasts with that for Puccinia striiformis f. sp. tritici (the wheat stripe rust pathogen) in 1979, which is considered to have been carried from Europe by man.(4)

Further variation observed in the stem rust pathogen was attributed to 'progressive increases in virulence'. In detailed studies involving host lines known to possess single genes for resistance and infected with a range of pathotypes, it was shown that several distinctive phenotypes could be obtained. Genetic studies showed that the same host genes were involved. Whereas three phenotypes might be explained on the basis of homozygosity and heterozygosity for corresponding pathogenicity alleles, no simple mechanism could be postulated to account for the greater range of variation in the pathogen.

Puccinia graminis tritici and P. graminis secalis

In 1956 Watson was joined by N.H. Luig, who was appointed as a research assistant and later as a research fellow, initially seconded from the New South Wales Department of Agriculture but later employed on funds provided by the Wheat Industry Research Council. This association continued until Watson's retirement and was highly productive. Watson and Luig extended the experimental work on somatic hybridisation to involve members of different form species. Over a period of twenty years they collaborated in the presentation of twenty-five papers, seven of which also had a third author. Early in their collaboration they demonstrated that new pathotypes could be obtained either by mutation or by somatic hybridization and their work largely concentrated on the two formae speciales, P. graminis tritici and P. graminis secalis.

In the 1950s, P. graminis secalis was the predominant rust type occurring on barberry plants in New South Wales tableland areas and in Tasmania. This forma specialis was well adapted to some grass species, including Agropyron repens and A. scabrum, but rust on wheat was rarely found in the vicinity of barberry plants. Watson and Luig showed that P. graminis tritici and P. graminis secalis could undergo a somatic hybridisation to produce forms intermediate between the two types. They concluded that P. graminis secalis could be considered to be a non-pathogenic or very weakly pathogenic form of P. graminis tritici with respect to wheat as a host. They warned of a possibility that wheat rust forms might derive virulence genes from P. graminis secalis enabling them to overcome particular resistance genes present in important wheat cultivars.

Increased pathogenicity on wheat was obtained following self-fertilisation of P. graminis secalis on barberry. Conversely, from hybrid populations it was found possible to select wheats with increased susceptibility to P. graminis secalis. Additionally, when wheat genes giving resistance to P. graminis tritici were added to wheats previously selected for susceptibility to P. graminis secalis, it was possible to demonstrate that P. graminis secalis may carry virulence genes matching well known wheat genes for resistance to P. graminis tritici. Later studies showed that similar genetic manipulations could be carried out with rye in relation to its responses to P. graminis tritici. The two formae speciales thus actually represent a single species with a continuous spectrum of genetic variability.

From laboratory studies, Watson concluded that one evolutionary pathway of variation in P. graminis tritici resulted from hybridization between the pathotype present in 1938 and a putative exotic pathotype that entered Australia about the year 1950. Watson and Luig demonstrated that rust hybrids selected from mixed infections of hosts with P. graminis tritici and P. graminis secalis were similar to forms frequently isolated from Agropyron scabrum and from barley. It was concluded that the latter were of somatic hybrid origin following the introduction of P. graminis secalis into Australia in the early 1950s. Watson's and Luig's conclusions relating to the role of somatic hybridisation in the evolutionary diversification of the stem rust pathogen were supported by results from isozyme studies made by D.R. Marshall and J.J. Burdon at the C.S.I.R.O. laboratories in Canberra.(5)

Axenic culture of P. graminis tritici

The successful axenic culture of P. graminis tritici at Sydney University by K.J. Scott and P.G. Williams and their colleagues(6) in 1966 was timely. Watson believed that this work would permit the development of experiments leading to a better understanding of the nature and mechanism of somatic hybridisation in the rust fungi. However, although mononucleate diploid cultures were obtained, no further results bearing on the asexual recombination process ensued.

Pathotype surveys and pathotype designations

Annual pathotype surveys commenced by Waterhouse were continued by Watson and his successors. These surveys have been a feature of the Sydney University rust programme for over sixty years. Rust samples were collected by field officers of the Departments of Agriculture in all Australian States and in New Zealand, and by many farmers, school teachers and other interested people in the wheat growing areas. These samples were forwarded to Sydney for pathotyping, and for this purpose Watson developed an extended series of indicator wheat testers. The information accumulated in this way permitted the recording and plotting over time of the origins and/or migrations of new and distinctive rust pathotypes. Although meaningful patterns were not observable in eastern Australia, regular movements from Western Australia to the east and from Australia to New Zealand were evident, as might be expected from prevailing weather patterns. Pathotypes first recorded in the west reached the eastern wheat areas quickly, and then appeared in New Zealand. Long distance east-to-west dispersals have been rare, although some pathotypes first occurring in the east have eventually appeared in Western Australia.

During the 1950s it became evident that early methods for the designation of pathotypes were inadequate because the host resistance testers being used were genetically different from those used as parents in breeding programmes and thus were not relevant to breeding needs. The number of differential tester stocks being used in the surveys was therefore extended to include the sources of resistance actually involved in the breeding work. Watson always favoured the use of as many indicator host genotypes as possible. He retained the old 'international race' designations, his laboratory being one of the few that continued to use them. With surveys based on genes relevant to the breeding programme together with others of minimal or no value, there resulted a clearer understanding of pathotype changes caused by direct selection on previously resistant cultivars in comparison with those resulting from apparent non-selective influences. Watson and Luig introduced new systems for pathotype designation for Puccinia recondita f. sp. tritici in 1961 and for P. graminis tritici in 1963. Both systems were open ended, and additions were made as knowledge expanded and as breeding needs required.

Strategies in breeding

In a letter to the editor of Nature in 1948, Watson outlined a long-term plan of breeding strategies to establish rust resistance in wheat cultivars, and he was committed to this plan for the remainder of his career. The strategies were not static but could be, and were, modified and developed with the passage of time.

The host/parasite interaction involves a two-sided battle. On the pathogen side, there is the battle against natural and artificial selection for resistance in the host. On the other side, the wheat plants, with the breeder's help, are battling against the ability of the pathogen to develop new virulence by sexual and parasexual genetic recombination and by mutation. For the development of sound breeding strategies, the wheat breeder must understand the genetic system and competence not only of the host, but also of the pathogen. Watson understood this situation, and relevant studies of the rust pathogens, made in collaboration with Luig, have been outlined.

In his graduate work at Minnesota Watson studied the inheritance of stem rust resistance in two Kenyan wheats and proved that a different resistance gene was present in each. He continued to be involved in host genetic analysis and realised the value of having near-isogenic lines carrying single genes for resistance. Using such lines, a team of collaborators was able to show that some resistance genes previously thought to be identical were in fact distinct alleles separable by their differential responses to the pathogen.

Watson supported E.P. Baker and colleagues in their work on wheat cytogenetics. In the early 1950s, aneuploid stocks developed by E.R. Sears in the U.S.A. were obtained and were used in the work. A cytogeneticist, Lucinda Wyndham, was appointed to collaborate in the work, funds for this purpose being made available by the C.S.I.R.O. Division of Plant Industry. With the adoption of the Wheat Industry Research Act and the imposition of compulsory research levies on farmers and matching grants provided by the Australian government, support for both the cytogeneticist position and Luig's position was provided by the Wheat Industry Research Council. The cytogeneticist position was subsequently occupied by C.J. Driscoll, B.A. Barlow and, since 1960, R.A. McIntosh. By the 1970s a significant number of genes for stem rust and leaf rust resistance were genetically mapped, chromosomally located, and formally described.

Watson was firmly convinced that the production of stable and durable resistance in wheat cultivars requires the use of many distinct resistance genes. Students of plant and animal evolution have long realised that the existence of an empty or inefficiently exploited niche offers an opportunity for episodic evolution. The diversification of the finches of the Galapagos Islands, as described by Lack,(7) provides a striking example of the importance of ecological opportunity. Watson himself realised that when a wheat cultivar, resistant to the available pathotypes, is widely grown, it provides just such an empty niche, and he appreciated that a resistance due to many genes would require the rust pathogen to acquire complex genetical recombinations or many separate mutations more or less simultaneously in order to break through to that empty niche.

Watson and his colleagues made genetical analyses of wheats exhibiting resistance from widely distributed locations throughout the world. Such cultivars often possessed combinations of genes determining both seedling and adult plant resistance. Genetical studies were also made of resistance in rye to both Puccinia graminis secalis and P. graminis tritici, and in barley to P. anomala.

It has been noted already that the resistances of Eureka and Gabo were short-lived. This was also true of Gamenya and Mengavi. In all four of these wheats, resistance was based on single genes, Sr6 in the case of Eureka and Sr11 in Gabo and its derivatives. Later cultivars, notably Gamut, Gatcher and Timgalen, each had several resistance genes, and all three had more durable resistance and extended useful lives as worthwhile cultivars.

There exist problems in the synthesis of cultivars with many resistance genes. The genes must be found by world-wide varietal surveys, or must be discovered in nature in wheat relatives, and then must be transferred to locally adapted types. Such genes, or the chromosome regions in which they occur, must be neither allelic nor closely linked in repulsion, and each must be separately monitored to ensure its retention in selected breeding lines. Watson's team developed a range of new tester stocks capable of distinguishing a wide range of pathotypes, using both seedling tests in a greenhouse environment and maturing plants under field conditions. By the use of carefully chosen pathotypes in the laboratory, the desired gene combinations were assembled.

Another strategy conceived by Watson for the production of complex resistance has had partial success. This was based on the availability of a detailed knowledge of rust pathotype variation on a global scale. Lines of wheat selected on a national basis were proposed to be sent to geographical locations predicted to have the most suitable pathotypes for confirming the presence of the desired gene combinations, or for distinguishing host genotypes that could not be determined locally. In order to obtain the basic information for such a programme, Watson assembled and distributed a collection of host tester stocks to many centres interested in wheat stem rust. The collection was sent out each year over the three-year period 1968-1970. Data were returned but it was not until 1983 that the results of the survey were finally processed and published in a monograph written by N. H. Luig.(8) Up to the present time, the information has not been applied in the way originally intended.

Still more ambitious was Watson's realisation that it was possible to develop new generations of resistant cultivars prior to the breakdown of the currently resistant ones in extensive cultivation. Songlen and Sunkota were selected in greenhouse tests against an induced mutant rust culture virulent on Timgalen seedlings at a time when that cultivar remained highly resistant in the field to the currently dominant rust pathotypes. Watson appreciated that success in such a strategy would require a combination of a detailed knowledge of the genetics of host resistance and adequate rust survey information for the prediction of likely changes in host/pathogen interactions.

It has been the adoption of these various strategies that has kept the northern wheat growing areas of eastern Australia free of stem rust for over 35 years.

Administrative achievements

Irvine Watson was a precise and humorous speaker, could capture an audience, and was a born negotiator and diplomat. A gifted meticulous investigator, he had a clear vision of his goals and a total dedication to his work. He was an organiser and a first-rate committee member. Important committees on which he served included the Wheat Industry Research Committee of N.S.W. (1966-1977), the N.S.W. Standing Committee on Wheat, the N.S.W. Wheat Improvement Committee, and the Commonwealth Wheat Industry Research Council (1967-1977), the last being a national body. He took part in the work of the International Centre for the Improvement of Wheat and Maize (CIMMYT) in Mexico, was editor of The Australian Plant Breeding and Genetics Newsletter, and was on the advisory committee of the Australian Journal of Agricultural Research. He was also instrumental in involving the University Plant Breeding Institute in the formation and management of the National Wheat Rust Control Programme.

The development of field stations

W. L. Waterhouse, working at the University of Sydney, and S. L. Macindoe, at the N.S.W. Department of Agriculture Experiment Station, Glen Innes, were both concerned with the wheat rust problem in north-western New South Wales. Both, independently, appreciated the need for field stations in that region if they were to have success in their rust resistance breeding programmes. Waterhouse at first used Hawkesbury Agricultural College for rust testing, and depended on farmer friends for the increase of breeding lines and for field performance testing. In 1945 he was able to establish a station at Curlewis, near Gunnedah, but was prevented by ill-health from active field work, which became the responsibility of Irvine Watson. This Curlewis station was the forerunner of the Narrabri station.

The Castle Hill Research Station

With the expansion of the wheat breeding programme following the Second World War, and the increased effort to incorporate and maintain resistance to stem rust, it became apparent that additional facilities were needed in order to conduct research and to rust-test breeding populations. The Curlewis station was too remote for the necessary research work, and Watson required a station close to Sydney. The University administration was not co-operative and suggested that the work could be done at an existing University farm at Badgerys Creek, despite evidence of unsuitable soils and the lack of a water supply necessary for the induction of regular rust infections. When Watson eventually located a suitable area of land, of about 10 hectares, at Castle Hill, the Vice-Chancellor and the University Finance Committee refused to purchase it. In desperation, Watson purchased the land himself and negotiated an arrangement whereby the University would rent the property for a period of ten years at a nominal rental of £1.

The University agreed to build a shed-cum-seedstore-cum-laboratory, to provide a small manager's fee, and to meet council and water rates. The first wheat plots were planted at the new farm in 1947. For many years the International Harvester Company provided a tractor and other farm implements on a rent-free basis. In his account of the development of the Plant Breeding Institute, Watson has described the various problems, including the control of rabbits, that confronted him during those early years.

In order to supplement the field work and to produce the inoculum required for field rust infection, Irvine Watson, his father and his field staff erected a series of small greenhouses. They provided their own labour, mixed the concrete and laid the floors, and assembled the timber frames. No doubt Irvine's youth spent on his father's farm equipped him for this kind of work. The glass exteriors for the greenhouse consisted of steel-framed windows that had been discarded during alterations to the University medical school, and the internal partitions were home-made plastic-covered fly screens. Such was the scarcity of funds for agricultural research!

With the retirement of Professor W. L. Waterhouse in 1952, the N.S.W. Flour Mill Owners Association sought a means of acknowledging his work and accepted a suggestion that they purchase and donate the Castle Hill property to the University. Voluntary collections from 47 New South Wales mills enabled the purchase of the property for £5,350 and also provided a research fund of £3,000. The actual area of land donated by the Flour Mill Owners Association was 19 acres, 2 roods and 25.75 perches. In later years the University purchased additional adjoining blocks.

In its early years, the Castle Hill Research Station was used mainly as a field testing site for the induction of rust infection, with four technical staff members contributing to the work programme. In the late 1950s a large water storage dam was constructed in order to overcome chronic water rationing frequently imposed at that time by the Sydney Water Board. The first stage of an office block was constructed in 1963, and an Officer-in-Charge (J.D. Oates) was appointed in 1964. Then the research staff, N.H. Luig and R.A. McIntosh and their technical assistants, were transferred from the University campus. McIntosh gained his Ph.D. with E.P. Baker in 1968. In subsequent years there were additions to the office building and expansions of the greenhouse facilities. More recent notable events were the introduction of the National Wheat Rust Control Programme in 1975, the appointment of Dante The as its Coordinator, and the advent of wheat stripe rust in Australia in 1979. From 1964 until his retirement, Watson kept almost daily contact with the station. Living nearby, he frequently visited and briefed the staff before leaving for the University campus.

The Castle Hill Research Station has now become too small for its vastly expanded rust testing and research functions. The encroachment of the rapidly growing metropolis of Sydney and soaring land values have precluded the purchase of additional land. Consequently a decision was made in 1983 to prepare for the eventual removal of the station to a new site at Cobbitty. Watson was saddened by this projected development, and discussed possibilities of using the existing facilities in conjunction with a separate field-testing site - an issue he had had to address more than thirty years earlier. Nevertheless, it was the foresight and entrepreneurial spirit shown by Watson in setting up the station just after the Second World War that has made the anticipated transfer to a larger and more modern complex financially feasible.

The I.A. Watson Research Centre, Narrabri

At a wheat breeding conference held in Wagga Wagga in 1956, it was resolved that more effort should be devoted to rust research. The N.S.W. Department of Agriculture agreed to appoint two staff members to assist the University programme, led by I.A. Watson, in the northern part of the State. This group was requested to concentrate on the production of high quality hard-grained rust resistant wheats of the Gabo type. A second group, in the State Department of Agriculture and led by A.T. Pugsley at Wagga Wagga, was to breed softer, high yielding wheats of the Javelin type. Both programmes were to be co-ordinated by the N.S.W. State Wheat Improvement Committee, which continues to function. The N.S.W. Department scientific officers joining the northern programme were E.M. Matheson and N.H. Luig, Matheson first being stationed at Narrabri.

With the passing of the Commonwealth's Wheat Industry Research Act in 1957, the N.S.W. State Wheat Research Committee was inaugurated to administer and allocate funds from a levy on New South Wales wheat growers. This committee comprised government, university and farmer representatives. An early decision was made by the committee to establish an Institute on the black soil plains of northern New South Wales and a site was selected for this purpose, 7 km north of Narrabri.

The Northwest Wheat Research Institute commenced operations in 1961, and three lines of research were initially pursued - wheat agronomy, pasture agronomy and wheat breeding. N.F. Derera was appointed as wheat breeder. In 1971, increased operating costs caused the Institute's activities to be restricted to the wheat breeding programme, with Derera as officer-in-charge. In the following years two additional wheat breeders (G.M. Bhatt and F.W. Ellison) and a cereal chemist, J. Noll (later replaced by D. Mares), were appointed, and an integrated breeding programme involving the Castle Hill and Narrabri groups was developed. J. Gyarfas was responsible for the day-to-day breeding activities at Castle Hill. The modus operandi and the working relationship between the two groups later served as a model for the service testing and germplasm enhancement components of the National Wheat Rust Control Programme.

On Watson's retirement in 1977, the Northwest Wheat Research Institute was renamed the I. A. Watson Wheat Research Centre in honour of his contribution to wheat improvement in Australia.

The Plant Breeding Institute

In 1973, the integration of the Castle Hill and Narrabri groups was reinforced by the establishment of the Plant Breeding Institute. In order to permit this, arrangements were made for the University to have a long-term lease of the Narrabri property, and the University accepted a long-term commitment to wheat breeding and wheat rust research that would extend beyond Watson's approaching retirement. The arrangement provided increased security to Institute staff, many of whom were employed on annually renewable industry grants, and increased the capacity of the University to attract further outside funding for its wheat programme. With the decision of the University to accept the invitation to administer the Institute, the N.S.W. Department of Agriculture decided to discontinue the previous co-operative programme and to commence an independent breeding effort at Tamworth. E. M. Matheson was transferred to Tamworth, but Luig was confirmed in his appointment to the rust programme at Sydney and Castle Hill.

The National Wheat Rust Control Programme

The damaging wheat stem rust epidemic in 1973-74 seriously affected the southern wheat areas of New South Wales as well as those in Victoria and South Australia. Perhaps this was partly a consequence of the decision of the N.S.W. Department of Agriculture in 1956 that the southern wheat breeding programme, led by A.T. Pugsley, should concentrate on the breeding of softer wheats with high yield, with rust resistance as a secondary consideration. The northern wheat areas of the State and those in Queensland were relatively unaffected by the epidemic, even though thay did receive high levels of rust inoculum from the south. The epidemic apparently resulted from a build-up of rust, especially in South Australia and southern New South Wales, during the previous, unseasonably wet summer. These high levels of inoculum combined with continuing above average rainfall in the 1973 wheat season and the growing of susceptible cultivars, provided the essential elements for the epidemic.

The aftermath of this epidemic was the introduction of a National Wheat Rust Control Programme funded by the Wheat Industry Research Council. This funding enabled the extension of the host screening and breeding work conducted by the Castle Hill Research Station to all wheat breeding programmes in Australia. The programme, which began in 1975, was organised to provide information and rust testing services on wheat materials submitted by breeding organisations Australia-wide. In addition, it undertook to add resistance genes, by backcrossing, to wheats nominated by breeders. This programme is now widely accepted by the Australian wheat industry as a model for interstate co-operation, although it has not yet fully achieved its initial objective, which was to have New South Wales completely protected from rust by 1980 and Australia so protected by 1985. The unexpected appearance of wheat stripe rust in 1979 has had a delaying effect on the original timetable.

Family life and retirement

In 1942, Irvine Watson married Loloma Deane, who had been a contemporary student in the Faculty of Science at the University of Sydney. They first met in the first-year botany laboratory in 1933.

In the later years of his professional career and in his retirement, Watson was troubled by heart problems, and his retirement for health reasons came two years before it was required by University regulations. In 1984 he underwent a multiple by-pass operation that sustained him for some time, but he died early in 1986. He is survived by his wife, two daughters, one son, and eight grandchildren.

Watson was a modest person. To his non-professional contacts he was known as 'Mr Watson' or 'Irvine' and many were unaware of his academic status. In retirement, his life centered around his family and the large garden surrounding his home. His delightful and unique humour was greatly appreciated by both his family and extended family contacts including close professional colleagues. As hobbies, he enjoyed both woodwork and metal work. He was fond of classical music, and he maintained an interest in the historical development of farming and farming families in New South Wales.

Irvine Watson continued a keen interest in the University's wheat rust and breeding programmes For some years he participated in rust testing and selection activities at Castle Hill, and at the time of his death he was conducting a small winter wheat breeding programme in his home garden. At all times he welcomed visits from colleagues and discussions of matters involving the wheat programme and the wheat industry. During his retirement he also did some writing; his account of the development of the Plant Breeding Institute was included in the Institute's 1985 annual report, and with F.C. Butler he published an account of national conferences in Australia and of other initiatives and developments relating to wheat rusts and rust research in Australia and elsewhere.

In conclusion, we can do no better than to quote Dr. Butler: 'Based on his outstanding record of achievement, Irvine Watson has rightly found, and I believe will ever retain, a widespread recognition as a world leader in the study and breeding of rust resistance in wheat'.(9)

Honours and awards

Irvine Watson was awarded medals and honours befitting his status and his contributions to human welfare. These included:

  • The Farrer Memorial Medal (1958). The medal was named after Australia's first great wheat breeder.
  • The E.C. Stakman Medal of the University of Minnesota (1966). Given for outstanding individual contributions to wheat improvement on a world-wide basis. Only one other Australian has received this award.
  • The Commemorative Medal of the International Wheat and Maize Improvement Centre, Mexico (1971).
  • The James Cook Medal of the Royal Society of New South Wales (1975), for contributions to human welfare.

Watson was appointed a Visiting Professor of the University of Minnesota in 1955, and was awarded the degree of Doctor of Science in Agriculture (honoris causa) by the University of Sydney in 1979. This was only the second time the award had been given. Additionally, he was affiliated with several learned Societies. His fellowships included:

  • Fellow of the Australian Institute of Agricultural Science (1964).
  • Foreign Member of the Soviet Academy of Agricultural Sciences (1972).
  • Fellow of the Australian Academy of Science (1975).
  • Foundation Fellow of the Australian Academy of Technological Sciences (1975).
  • In the New Year Honours List for 1977, for services rendered, Watson was named a Commander of the Most Excellent Order of the British Empire (C.B.E.).

About this memoir

This memoir was originally published in Historical Records of Australian Science, vol.7, no.4, 1989. It was written by R.A. McIntosh, Director of Rust Research, University of Sydney Plant Breeding Institute; and S. Smith-White, Emeritus Professor of the University of Sydney.


For the preparation of this memoir we wish to acknowledge the assistance of Mrs. Loloma Watson and of Irvine's career associates, Dr. F.C. Butler, N.F. Derera, Professor B.J. Deverall, Dr. N.H. Luig, and Dr. K.S. McWhirter. We also received information from Dr. E.P. Baker and from Professor N.H. White.


  • (1) C.R. Wharton, Jr., 'The Green Revolution: Cornucopia or Pandora's Box', Foreign Affairs, 47 (April 1969)
  • (2) Waterhouse, W.L., 'Australian rust studies. I', Proc. Linn. Soc. of N.S.W., 54 (1929), 615-680.
  • (3) Pontecorvo, G., and Kafer, E., 'Genetic analysis based on mitotic recombination', Advances in Genetics, 9 (1958), 71-104.
  • (4) Wellings, C.R., McIntosh, R.A. and Walker, J., 'Puccinia striiformis f.sp. triciti in eastern Australia - possible means of entry and implications for plant quarantine', Plant Pathology, 36 (1987), 239-241.
  • (5) Burdon, J.J., Marshall, D.R. and Luig, N.H., 'Isozyme analysis indicates that a virulent cereal rust pathogen is a somatic hybrid', Nature, 293 (1981), 565-566.
  • (6) Williams, P.G., Scott, K.J. and Kuhl, J.L., 'Vegetative growth of Puccinia graminis f. sp. triciti in vitro', Phytopathology, 56 (1966), 1418-1419; Williams, P.G., Scott, K.J., Kuhl, J.L. and Maclean, D.J., 'Sporulation and pathogenicity of Puccinia graminis f. sp. tritici grown on artificial medium', Phytopathology, 57 (1967), 326-327.
  • (7) Lack, D.L., Darwin's Finches (Cambridge, 1947)
  • (8) Luig, N.H., 'A survey of virulence genes in wheat stem rust, Puccinia graminis f. sp. triciti', Advances in Plant Breeding, 11 (1983); supplement to Plant Breeding, 198pp.
  • (9) Butler, F.C., 'A tribute to the late Professor Irvine Armstrong Watson', North West and Hunter Valley Magazine, 14 (No.47) (1986).

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