Allohexaploids in the Genus<i>Brassica</i>

Abstract

Allohexaploid Brassica hybrids (2n = AABBCC) have been the subject of plant breeding and research for many years, both to increase our understanding of polyploid plant evolution and to benefit plant breeding. This review summarizes and evaluates the different approaches to producing these hybrids using the six interrelated crop species (three diploids and three allotetraploids) of the famous “U’s Triangle” as starting material. Special emphasis is given to cytogenetic and marker-based analysis of abundant non-homologous chromosome recombination events, and their implications for plant fertility. We discuss mechanisms by which allohexaploid Brassica hybrids could stabilize meiosis and give future perspectives on the establishment of a new allohexaploid Brassica crop.