The Brittle Rachis Trait in Species Belonging to the Triticeae and Its Controlling Genes and .

In many non-cultivated angiosperm species, seed dispersal is facilitated by the shattering of the seed head at maturity; in the Triticeae tribe, to which several of the world's most important cereals belong, shattering takes the form of a disarticulation of the rachis. The products of the genes and are both required for disarticulation to occur above the rachis nodes within the genera (barley) and (wheat). Here, it has been shown that both and are specific to the Triticeae tribe, although likely paralogs ( and ) are carried by the family Poaceae including Triticeae (the donor of the bread wheat D genome) lacks a copy of and disarticulation in this species occurs below, rather than above the rachis node; thus, the product of appears to be required for disarticulation to occur above the rachis node.