Hybridization and Introgression

Abstract

The study of natural hybridization using secondary metabolites, particularly flavonoids, attracted a good deal of attention following the pioneering work of Ralph Alston and his colleagues at the University of Texas. Sorting out the complex patterns in populations of hybridizing Baptisia species by morphological means alone was extremely difficult bordering on impossible. The discovery that flavonoids could be used as markers led to a much deeper understanding of the system than was possible by other means, at least at that time (Alston and Turner, 1963b; McHale and Alston, 1964; Baetcke and Alston, 1968). It was not long before flavonoid analysis was applied to hybridization problems in Asteraceae. Early studies by Torres and Levin (1964) on Zinnia and on Liatris (Levin, 1967), were followed by work from Ownbey’s group at Washington State University on Tragopogon (e.g., Beltzer and Ownbey, 1971)