Plant Breeding

Most food plants brought from Europe to the United States in the seventeenth century failed to prosper widely. Some could not be grown successfully anywhere, because they could not adapt to the climate, or were susceptible to newly-encountered pests or diseases. At the beginning of the nineteenth century, the range of varieties available for any given plant was extremely limited. Apples, however, were an exception. This fruit crop had benefited from a number of chance varieties such as the Newtown Pippin (about 1700), the Baldwin (1742), and the Jonathan (1829). However, it was in the more typical context of low diversity that Thomas Jefferson said "the greatest service that can be rendered any country is to add a useful plant to its culture."

The Rural Visiter, a periodical published in Burlington, Vermont, in 1810, ran a series of extracts from Knight's "Treatise on the Culture of the Apple and Pear." Knight's grafting methods were further described by James Thatcher in his American Orchardist in 1822. In this way the principles behind Knight's work became understood in the United States.

The first variety of a fruit tree to be bred in the United States was a pear produced by William Prince, around 1806. He crossed St. Germain with White Doyenne (the pollen donor), and from the seed selected a variety known as Prince's St. Germain. Later, further improvements of the pear were made by the discovery of natural hybrids between the European pear (binomial) and the introduced Chinese sand-pear (binomial). The Kiefer, Le Conte, and Garber pears all arose in this fashion, and allowed pear cultivation to extend beyond California into the eastern and southern states.