I originally wrote this story in August 2021 after a friend and former colleague, Dr Glenn Bryan¹ posted a link on his Facebook page to a story—Treasure trove could hold secrets to potato problems—that had just appeared in the online edition of Dundee’s The Courier.

It was about the Commonwealth Potato Collection (CPC) that is held at The James Hutton Institute (JHI) at Invergowrie, just west of Dundee.

Until a couple of years ago (when he retired) Glenn led the Potato Genetics and Breeding Group at JHI, with Gaynor McKenzie as the CPC curator, a position she still occupies.

The Commonwealth Potato Collection has a long and distinguished history, going back more than 80 years. It is one of a handful of potato germplasm collections around the world in which breeders have identified disease and pest resistance genes to enhance the productivity of cultivated varieties. The CPC is particularly important from a plant quarantine perspective because the collection has been routinely tested and cleaned for various pathogens, particularly seed-borne pathogens.

It is a collection with which Steph and I have both a personal and professional connection, from the 1970s and 80s. It’s also the legacy of one man, Professor Jack Hawkes (1915-2007) with whom I had the privilege of studying for both my MSc and PhD degrees.

Let me tell that story.

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In December 1938, a young botanist—just 23 years old the previous June—set off from Liverpool, headed to Lima, Peru to join the British Empire Potato Collecting Expedition to South America, the adventure of a lifetime.

John ‘Jack’ Gregory Hawkes, a Christ’s College, Cambridge graduate, was destined to become one of the world’s leading potato experts and a champion of the conservation and use of plant genetic resources for food and agriculture.

He was the taxonomic botanist on the 1939 expedition, which was led by experienced plant collector Edwards Kent Balls (1892-1984). Medical doctor and amateur botanist William ‘Bill’ Balfour Gourlay (1879-1966) was the third member of the expedition. Balls and Gourlay had been collecting plants in Mexico (including some potatoes) in 1938 before moving on to Peru for the ‘Empire’ expedition.

The expedition had originally been scheduled to start in 1937, but had to be delayed because of ill health of the original expedition leader, Dr PS Hudson, Director of the Empire Bureau of Plant Breeding and Genetics in Cambridge. Jack had been hired as his assistant.

Whilst waiting for the expedition to get underway, Jack took the opportunity—in August 1938—to visit Leningrad to pick the brains of Russian botanists, Drs SM Bukasov, VS Juzepczuk, and VS Lechnovicz who had already collected potatoes in South America. Jack openly acknowledged that ‘as a raw recently graduated student, [he] knew very little about potatoes’.

Not only did Jack receive useful advice from these knowledgeable botanists, but he also met with the great geneticist and ‘Father of Plant Genetic Resources’ Nikolai Vavilov on several occasions during his visit to Leningrad and Moscow, ‘an experience that changed [his] life in many ways’. Vavilov had a profound effect on Jack’s subsequent career as an academic botanist and genetic resources pioneer. Alas there do not appear to be any surviving photos of Jack with Vavilov.

In Leningrad, Jack took this photo (right) of a wild potato species that had been described as Solanum vavilovii by Juzepczuk and Bukasov in 1937. Sadly that name is no longer taxonomically valid, and vavilovii is now considered simply as a variant of the species Solanum wittmackii that had been described by the German botanist Friedrich August Georg Bitter in 1913.

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The Empire expedition lasted eight months from January 1939, covering northern Argentina, Bolivia, Peru, Ecuador, and ending in Colombia (a country where Jack was to reside for three years from 1948 when he was seconded to establish a national potato research station near Bogota).

More than 1150 samples of cultivated and wild potatoes were collected in these five countries as well as a further 46 samples collected by Balls and Gourlay in Mexico in 1938.

Here is a small selection of photographs taken during the expedition (and a link to an album of photos).

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By the time the expedition ended in early September 1939, war with Germany had already been declared, and Jack’s return to the UK by ship convoy from Halifax, Newfoundland was not as comfortable as the outbound voyage nine months earlier, docking in Liverpool early in November.

Jack published an official expedition report in March 1941. Then, in 2003, he published an interesting and lengthy memoir of the expedition, Hunting the Wild Potato in the South American Andes.

In December 2021, my friend Dr Abigail Amey and I published a website (with permission of the Hawkes family) about Jack’s experiences of the 1938-39 expedition, as well as others to the USA, Mexico, and Central America in 1958, and Bolivia in 1971. Just click on the red box below (and others) to open the links.

The website also has several of Jack’s original 16mm films (which we were able to digitise through a special grant from the Crop Wild Relatives Project at Kew and the Crop Trust).

Potato tubers (and presumably seeds) were shipped back to the UK, and after a quarantine inspection, were planted out in a glasshouse at the Potato Virus Research Station, Cambridge whose director was the renowned botanist (and originally a medical doctor) Redcliffe Nathan Salaman, author of the seminal work on potatoes, The History and Social Influence of the Potato, first published in 1949 and reprinted with a new introduction by Hawkes in 1985. I jealously guard the signed copy that Jack gave me.

On his return to the UK in 1939 Jack began to study the collected germplasm, describing several new species, and completing his PhD thesis (supervised by Salaman) at the University of Cambridge in 1941.

Among the species identified in the course of Jack’s dissertation research was Solanum ballsii from northern Argentina, which he dedicated to EK Balls in a formal description in 1944. However, in his 1963 revised taxonomy of the tuber-bearing Solanums (potatoes), Jack (with his Danish colleague Jens Peter Hjerting, 1917-2012) recognized Solanum ballsii simply as a subspecies of Solanum vernei, a species which has since provided many important sources of resistance to the potato cyst nematode.

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The 1939 germplasm was the foundation of the Empire Potato Collection. When the collection curator Dr Kenneth S Dodds was appointed Director of the John Innes Institute in Bayfordbury in 1954, the collection moved with him, and was renamed the Commonwealth Potato Collection.

By the end of the decade (or early 1960s) the CPC was on the move again. This time to the Scottish Plant Breeding Station (SPBS) at Pentlandfield just south of Edinburgh when Dr Norman W Simmonds moved there in 1959. He rose through the ranks to become the station’s Director.

Dodds and his colleague Dr GJ Paxman traveled through South America during 1959-60, and their research on the genetics of diploid potatoes was based on some of the material collected. Dodds and Simmonds also collected potatoes in early 1963.

But that was not the end of the CPC’s peripatetic existence. It remained at the SPBS until the early 1980s, when the SPBS amalgamated with the Scottish Horticultural Research Institute (which became the Scottish Crop Research Institute or SCRI, and now known as the James Hutton Institute), and the collection moved to its present site near Dundee.

Today, the CPC comprises some 1500 samples or accessions of about 80 wild and cultivated potato species. And over two-thirds were collected by Hawkes himself. Another 9% of the collection were collected by Dodds and his colleagues, as mentioned earlier. The remainder represent donations over the years from various individuals and institutions.

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I am not sure how much the CPC grew in the intervening years, but there was a significant boost to the size and importance of the collection around 1987. Let me explain.

As I already mentioned, Jack spent three years in Colombia from 1948, returning to the UK in 1951 when he was appointed Lecturer in Taxonomy in the Department of Botany at the University of Birmingham. He was given a personal chair as Professor of Taxonomic Botany in April 1961, and became Head of Department and Mason Professor of Botany in July 1967. He remained at Birmingham until retirement in September 1982.

It was during his Birmingham years that Jack’s work on the tuber-bearing Solanums expanded significantly with several important monographs and taxonomic revisions published, based on his own field work over the years and experimental studies back at Birmingham on the potato samples he brought back to the UK and which formed an important collection in its own right. Because of the quarantine threat from these seeds (particularly of sexually-transmitted pathogens or new variants of potato viruses already present in the UK), Jack had a special quarantine licence from the then Ministry of Agriculture, Fisheries and Food (MAFF, now DEFRA) to maintain his collection at Birmingham.

In 1958, with Peter Hjerting and young research assistant Richard Lester (who later joined the Department of Botany as a Lecturer), Jack made a six month expedition to the USA , Mexico, and Central America.

Here is another account of that trip from the University of Birmingham Gazette. Besides potatoes, many other species were made for other institutions and botanic gardens.

Just three months after I arrived at Birmingham in September 1970 to enrol on the MSc course on plant genetic resources, Jack was off on his travels once again, this time to Bolivia accompanied by Peter Hjerting once again, his research assistant Phil Cribb and, in South America by Zósimo Huamán from the International Potato Center (CIP) and Moisés Zavaleta and others from Bolivia.

This is the official trip report. Here are some images from the 1971 expedition, courtesy of Phil Cribb.

Jack and Peter made another trip to Bolivia in 1974 (with research assistant Dave Astley), and another in 1980. They published their monograph of The Potatoes of Bolivia in 1989.

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In September 1971, Zósimo Huamán and Moisés Zavaleta came to Birmingham to study on the genetic resources MSc course. In that same cohort was a young botanist, Stephanie Tribble, recently graduated from the University of Wales – Swansea (now Swansea University). During the summer of 1972, Steph and I became ‘an item’, so-to-speak. However, by then I was already making plans to leave the UK and join CIP in Lima by January 1973, and on graduation, Steph was keen to find a position to use the experiences and skills she had gained on the course.

Just at that time, a Scientific Officer position opened at the SPBS, as assistant to Dalton Glendinning who was the curator of the CPC. Steph duly applied and was appointed from about October that year. Jack must have supported her application. Coincidentally, the MSc course external examiner was no other that Norman Simmonds who met Steph during his course assessment.

I moved to Peru in January 1973, and within a few days discovered that Jack had mentioned Steph to CIP’s Director General, Richard Sawyer. Well, to cut a long story short, Steph was offered a position as Assistant Geneticist at CIP, to support management of CIP’s large potato collection, similar to the role she’d had at Pentlandfield. She resigned from the SPBS and joined me in Lima in July that year. We married there in October, remaining with CIP in Peru and Central America for another eight years.

In April 1981 I was appointed Lecturer in Plant Biology at Birmingham, 18 months before Jack’s retirement, the aim being that I would assume Jack’s teaching commitments on the MSc course. When I also took over the Hawkes potato collection in 1982, I had high hopes of identifying funding for biosystematics and pre-breeding research, and continuing the Birmingham focus on potatoes.

That was not the case, and as the collection needed a dedicated glasshouse and technician I could not justify (nor financially support) holding on to such valuable research space. And, in any case, continuing with the Hawkes collection was actually blocking the opportunities for other potato research because of the MAFF-imposed restrictions.

So, with some regret but also acknowledging that Jack’s collection would be better placed elsewhere, I contacted my colleagues at the CPC to see if they would be interested to receive it—lock, stock, and barrel. And that indeed was what happened. I’m sure many new potato lines were added to the CPC. The germplasm was placed in quarantine in the first instance, and has passed through various stages of testing before being added officially to the CPC. Throughout the 80s and 90s Jack would visit the CPC from time-to-time, and look through the materials, helping with the correct identification of species and the like.

Jack’s interest in and contributions to potato science remained with him almost up to his death in 2007. By then he had become increasingly frail, and had moved into a care home, his wife Barbara having passed away some years previously. By then, Jack’s reputation and legacy was sealed. Not only has his scientific output contributed to the conservation and use of potato genetic resources worldwide, embodied in the CPC that he helped establish all those decades earlier, but through the MSc course that he founded in 1969, hundreds of professionals worldwide have continued to carry the genetic conservation torch. A fine legacy, indeed!

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¹ Glenn and I go back almost 30 years when, as a young scientist at the John Innes Centre (JIC) in Norwich, he was a member of a rice research project, funded by the British government, that brought together staff at the International Rice Research Institute (IRRI) in the Philippines where I was Head of the Genetic Resources Center, the University of Birmingham (where I had been a faculty member for a decade from 1981), and the JIC to use molecular markers to study IRRI’s large and globally-important germplasm collection conserved in its International Rice Genebank.

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• Originally published on 24 August 2021.