Modern varieties have mostly been bred post-World War II. Most modern varieties can also be described as commercial varieties, bred by seed companies and for commercial growers. They include most F1 hybrids (a few were created pre-WWII) and all genetically modified (GM) varieties.

Most modern varieties were bred through a scientific process involving knowledge of plant genetics and measurements of yield etc during selection.

F1 hybrids are the first generation (F1) progenies resulting from crossing carefully-selected, closely-inbred parental lines. Crops of F1 hybrids are very uniform in growth and generally vigorous with a high yield. A few are heirloom varieties, bred pre-World War II; these are rare, not least because the closely-inbred parental lines lose viability. F1 hybrid can also be organics, depending on how they are grown.

GM varieties are not sold to UK and EU gardeners at present but ones that are precisely engineered seem likely to be allowed in the near future, at least in the UK.

Heirloom, sometimes called heritage, varieties are usually considered to be ones bred pre-World War II and passed from one generation to the next (as other heirloom objects are). A few may date from even the medieval period.

They were mostly bred by gardeners and smallholders; some were chance seedlings. They were selected empirically (by observation of growth habit, yield, taste etc) generally in gardens and smallholdings and without modern pesticides and fertilizers. This gives them a general ‘fitness for purpose’, the main reason for their popularity.

Heirloom varieties generally remain true-to-type over the generations and, as such, their seeds are easy to produce in the open field and as such are open-pollinated. This property makes them fit for the purposes of even small seed multipliers so the seed is usually relatively cheap.

Established varieties are modern varieties which have stood the test of time (at least 20-30 years) as gardeners’ favourites.

Participatory plant breeding (PPB) involves the users of the new varieties, for the purposes of this website gardeners, working with modern plant breeders and sometimes also other scientists to breed new varieties suited to their conditions.

Participatory varietal selection (PVS) similarly involves the users of the new varieties (again gardeners for the purposes of this website) working together to identify the best varieties for their conditions, often with scientists aiding the process.

Citizen science involves public participation and collaboration in scientific research generally. Participatory varietal selection and participatory plant breeding thus come under its broad umbrella.

Evolutionary plant breeding (EPB) emphasizes the creation of varieties containing sufficient genetic diversity such that the different environments each crop finds itself in is able to select improved forms for that environment. EPB can be conflated with PPB, perhaps because both are favoured by the organic movement.