The triangle of U is a theory about the evolution and relationships between members of the plant genus Brassica. The theory states that the genomes of three ancestral species of Brassica combined to create three of the common modern vegetables and oilseed crop species. It has since been confirmed by studies of DNA and proteins.
The theory was first published in 1935 by Woo Jang-choon (Hangeul: 우장춘), a Korean-Japanese botanist who was working in Japan (where his name was Japanized as "Nagaharu U", the Japanese reading of his name). Woo made synthetic hybrids between the diploid and tetraploid species...