Until fairly recently text books about tropical crops written by colonial agriculturists often refereed to native farmers in blatantly racist language, describing ‘conditions of primeval savagery almost beyond imagination’. However, these farmers were often so successful as plant breeders that it is frequently impossible to determine from which wild species their crops were originally derived. In stark contrast, of the few plant species taken into cultivation within the British Isles many are almost indistinguishable from those still growing in the wild state. Good examples of this are the red and black currants and their close relative the gooseberry. The white currant is simply an albino red currant. All three of these species can be found growing wild in Britain in hedges and wooded areas, where they differ so little from the cultivated types that some have questioned their claim to be truly native. The reason for this is two-fold: firstly, birds regularly transport fruit seeds from gardens and allotments and deposit them in the countryside. Once over the garden wall these escapees fraternised with their truly wild neighbours, to the extent that it is now often impossible to distinguish feral plants from those of mixed or wild ancestry. The second reason for wild currants and gooseberries being so similar to those found in gardens is that their domestication is surprisingly recent. Both red and black currants appear not to have been cultivated in Britain before the sixteenth century, although they must have been picked from the wild and used medicinally since at least Roman times. In fact until the eighteenth century black currants were regarded as stinking and loathsome. In contrast gooseberry bushes were being imported from France for Edward I by the thirteenth century.
The greater antiquity of gooseberry cultivation partly explains why it is still possible to purchase in excess of 200 hundred different gooseberry varieties, while there are less than thirty different types of red or black currant available. However, the main reason for this difference is the ‘gooseberry club’ craze, which swept across the north of England from Lancashire in the early nineteenth century. Although the main purpose of these clubs was to compete to produce the largest fruit, they also produced a range of different coloured fruit. The seven hundred plus types of gooseberry that existed at the time not only contained green and red fruited varieties but also, yellow, white, blue and black and even striped ones. Today, although a few gooseberry clubs still survive sadly most of these different gooseberries do not.
One of the very few ways in which domesticated currants and gooseberries differ from those growing in the wild is in their sexual preferences. In their natural condition all three species contain incompatibility mechanisms within their flowers which ensure that if by chance they are self-pollinated then fertilisation and seed production is prevented and the flower fails to produce a fruit. As might be expected this tends to limit the production of fruit and thus this aversion to self-fertilisation has been selected out of cultivated plants. This phenomenon has been repeated many times during the domestication of crops. The loss of their incompatibility mechanism may be responsible for reducing the barrier to crossing between species. Not only are red and black currants able to hybridise with each other and with gooseberries, but this botanical incest also extends to include other family members from the rest of Europe and North America.
Unfortunately the transportation of currants and gooseberries across the Atlantic has had disastrous consequences. Black currants were introduced to America in 1629 and were widely grown until the 1890s. Then it was discovered that they were acting as a reservoir for a fungal disease called white-pine blister-rust, which had devastating effects on local pine trees. As a consequence of this the growing of black currants is illegal in many parts of America. In the reverse direction the importation of the American gooseberry was responsible for the introduction of gooseberry mildew into Britain in 1905. Although the American gooseberry is immune to this fungal disease, the leaves of European species become covered in white powder and the fruit turn into small brown blobs. The commercial cultivation of gooseberries in Britain has never recovered from this infection. The new import from America, although immune to mildew has been unable to supplant the native gooseberry, because as might be expected, it has poor taste. Modern mildew resistant varieties are therefore often hybrids between the American and European species.