Some insights into morphophysiological traits associated with cereal yield increases in mediterranean environments

摘要

The lack of identification of appropriate morphophysiological traits has been a major factor preventing progress in improving yield in water-limited environments, as well as the reason why plant breeders have not adopted more analytical approaches for selection. Based on the single framework established by Passioura's identity, the critical traits that currently show substantial potential to improve yield under Mediterranean drought conditions are discussed. Particular emphasis is given to single traits which integrate the function of the crop either at a higher level of organization (i.e. canopy), or according to a part of the plant cycle (e.g. grain filling) or both. The potential uses of carbon isotope discrimination and several substitutive approaches, as well as remote sensing techniques, are discussed. Finally, attention is devoted to the photosynthetic performance of the ear. For cereals under Mediterranean conditions, where terminal drought stresses are common, the ear becomes the main photosynthetic organ during grain filling.