19 Jan 2016
You might not think of gardening as science. But home gardeners have long been enthusiasts for experimentation of all kinds, and gardens have often doubled as experimental laboratories.
In a beautifully constructed lecture organised by SCI's Cambridge and Great Eastern Group on 3 December 2015, Helen Anne Curry, Department of History and Philosophy of Science at Cambridge University, described the efforts of amateur gardeners to create their own new varieties of flowers, fruits, and vegetables throughout the twentieth century, many of them using techniques taken straight from the then-latest findings in genetics research. The approaches embraced by amateurs ranged from fairly straightforward methods such as selection and hybridisation to more unusual techniques such as X-raying seeds, spraying shoots with toxic chemicals, and exposing flower buds to radioisotopes.
The lecture started with a discussion of plant breeding at the turn of the twentieth century. Plant breeding first became a truly professionalized activity around this period, and also attracted a great deal of public attention. The place of plant breeding in the American imagination at this time is best illustrated by the attention given to the horticultural entrepreneur Luther Burbank, who was regarded by the American public as an inventive genius on a par with Henry Ford and Thomas Edison. Burbank’s breeding methods, which included selective breeding, grafting trees and hybridisation, were described in numerous publications for the general public. Many gardeners and other amateurs were in turn inspired to try their own hand at “burbanking” flowers following these descriptions.
The talk then moved to the less familiar topic of the use of X-ray irradiation in plant breeding. This technique was applied in the 1920s and 1930s, soon after it was found that exposure to X-rays could cause genetic mutation. Because genetic mutations were assumed to be the source of heritable variations that differentiated one plant variety from another (and indeed one species from another), many breeders assumed that induced mutation would provide a way to speed up their breeding efforts by creating many variations on demand. Where professionals went, amateurs followed. Adventurous amateur gardeners sought out X-ray sources in universities and hospitals to see what new varieties they could create. There were precious few successes generated by those who attempted this approach, whether professional or amateur, but the transient popularity was an indication of public enthusiasm for new genetic technologies.
A more successful approach to generating heritable variations 'on demand' in plants was achieved in 1937 through the application of colchicine, a compound that leads to chromosome doubling when applied to many plant species. Chromosome doubling had long been of interest to breeders because it sometimes resulted in the doubling of fruit or flower size, which of course could be highly desirable for commercial producers, and was thought to enable the creation of new hybrid types as well. Because colchicine was already widely available (it had long been a treatment for gout) it was very quickly taken up by amateurs who were eager to see whether they could create giant plants and fabulous new hybrids in their own gardens.
After World War II, plant breeders again took up experimentation with radiation-only this time the emphasis was not on x-rays but on radioisotopes and other radiation sources made available in the Atomic Age. Even with so exclusive a technology as nuclear energy, adventurous amateurs were eager to try new breeding approaches for themselves. For example, the self-taught breeder John James induced mutation by scraping radium-containing paint from watch dials and applying this onto budding roses. Those who were unwilling to expose seeds to radiation themselves simply purchased irradiated seeds-and then compared their results through organizations such as the 'Atomic Gardening Society,' a UK-based group.
As Curry pointed out in conclusion, many observers describe the current trend of 'Do-It-Yourself Biology' - in which the tools of contemporary molecular biology are wielded by science enthusiasts in their own homes or self-organized clubs - as an unprecedented engagement of amateurs with genetic science and technology. Yet it is clear that amateurs have long been inspired to tinker with genes and chromosomes, making DIY Bio only the most recent iteration of a long-standing trend.
Andrew Howe
Treasurer, SCI Cambridge and Great Eastern Committee
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