In many cases, MAS provides an important
alternative to phenotypic selection. However,
the success of markers depends on their reliabil-
ity in predicting phenotype. Many key stresses
associated with rapid environment changes, no-
tably drought and salinity tolerance, are com-
plex and highly variable. For these types of
traits, it is necessary to dissect tolerance into
component contributory traits and to identify
genetic regions encoding the traits, rather than
overall plant tolerance (6, 15, 16). However, this
genetic approach requires high-throughput phe-
notyping (phenomics) (17) (Box 1). Phenomics
also allows screening of populations for par-
ticular traits and will facilitate the introgression
of novel variation from wild germplasm. Phe-
nomics will enable tighter definition of the prop-
erties of molecular markers, allowing introgression
of appropriate combinations of tolerance traits
into commercial varieties for particular target
environments.