Plant Breeding

The genetic discoveries of Gregor Mendel with pea plants, first published in 1866, were revolutionary, although Mendel's work remained obscure until translated from German into English by William Bateson in 1903. Nevertheless, the relationship between pollen lodging on the stigma and subsequent fruit production was realized long before Mendel's work. The first hybrid produced by deliberate pollen transfer is credited to Thomas Fairchild, an eighteenth-century, English gardener. He crossed sweet william with the carnation in 1719, to produce a new horticultural plant.

Towards the end of that century, Thomas Andrew Knight, another Englishman, demonstrated the practical value of cross-pollination on an unprecedented scale. He produced hybrid fruit trees by cross-pollination, and then grafted shoots of their seedlings onto established, compatible root stalks. This had the effect of greatly shortening the time until fruit production, so that the horticultural success of the hybridization could be evaluated. After selecting the best fruit, the hybrid seeds could be planted, and the process of grafting the seedlings and selection could be continued. The best hybrids, which were not necessarily stable through sexual reproduction, could be propagated by grafting. Thomas Knight was also responsible for the first breeding of wrinkled-seeded peas, the kind that provided Mendel with one of his seven key characters (round being dominant, with one allele sufficient for expression; wrinkled being recessive, requiring two copies of the allele for expression).