Breeding for shoot vigour modifies below-ground architecture and weed competitiveness in wheat (Triticum aestivum L.)

Abstract

Weeds represent a serious and ongoing problem to wheat production in Australia. The increasing cost of weed infestation and the rise of herbicide resistance suggest the critical need for an integrated approach to weed management. One strategy is to develop more vigorous wheat cultivars that can better compete with weeds for light above ground and water and nutrients below-ground. Root traits that help plants explore more soil and extract its resources include root length, root depth, branching pattern, root angles and root hair length. To evaluate the relationship between shoot vigour and below-ground competitiveness in wheat, we measured several root traits in a set of CSIRO pre- breeding lines selected for high early shoot vigour and compared them with commercial and historic wheat cultivars and a triticale cultivar. Root biomass, total root length and root depth of the high vigour lines were greater than the commercial cultivars. We conclude that the selection for increased early shoot vigour also modified many major root traits potentially associated with below-ground competitiveness.