During the 1960s Bennett worked at the (now-defunct) Scottish Plant Breeding Station, where she studied micro-evolution and the origins of genetic diversity, with a focus on forage and seed crops.
In 1964 she wrote the internationally influential paper “Plant Introduction and Genetic Conservation: Genecological aspects of an urgent world problem”.
In it, she coined the term "genetic resources" to express the idea that genes themselves are a resource - one that has been disappearing rapidly, as diverse traditional peasant seeds have been replaced by uniform modern, elite seeds.
When an elite variety stops giving acceptably high yields due to disease, or some other factor, the plant breeders turn to the traditional varieties, or even to wild relatives, in search of genes that can confer the necessary resistance.
[2][3] In 1982 Bennett resigned from the FAO in protest at the influence of corporate interests in the organisation's decision-making processes.