We are told that the first part of the process is to select the very smallest seeds from the smallest plants, which is not at all unlikely, but I cannot speak to the fact from my own observation.

fortuniana also serves as a valuable rootstock in Australia and the southern regions of the United States. By Robert Fortune. 2012.

Robert Fortune (16 September 1812 – 13 April 1880) was a Scottish botanist plant hunter and traveller best known for introducing tea plants from China to India.