Genetic Analyses of the Heteromorphic Self-Incompatibility (S) Locus in Buckwheat

Abstract Understanding the molecular mechanism of heteromorphic self-incompatibility (SI) is essential to control the mating behavior in breeding and is useful for future development and improvement of self-compatible (SC) lines in buckwheat. In this chapter, we briefly summarize genetic analyses of the heteromorphic SI as well as the developments of SC lines and update recent progress on genomic characterization of the S -locus or S supergene complex regulating the heteromorphic SI. After an introduction of SI systems in buckwheat and other plants, an establishment of buckwheat SC line Kyukei SC2 and its physiological feature are described with its implication on the genomic structure of the S supergene complex. Then, we overview the latest studies on identification of genes present in the S -locus and introduce its potential application to understand the evolutionary history of buckwheat cultivation.