A barley breeding programme based on an ideotype

SUMMARY An attempt has been made to produce barley lines in accordance with an ideotype designed in 1968. Current lines are early maturing, uniculm, six-row barleys, of medium height, high harvest index, and moderate resistance to lodging. However, they have lax leaves of medium length, in contrast to the short, erect leaves of the ideotype. When sown in narrow rows at a rate three times that of tillered lines, they have given grain yields greater than the two- and six-row tillered controls, especially in favourable seasons, but less so in dry years. The quality of the grain has not been examined. In the absence of plasticity in number of tillers, uniculm lines show increased plasticity in number of grains per ear and weight per grain. It is possible that the uniculm habit, apart from effects on morphology and maturity, may permit more exacting selection of high-yielding plants than is possible among plants each comprising many mutually competing culms.