Drought and salt tolerances in wild relatives for wheat and barley improvement.

Drought and salinity are the major abiotic stresses that dramatically threaten the food supply in the world. Tribe Triticeae, including wheat and barley, possesses tremendous potential for drought and salt tolerance that has been extensively and practically identified, tested, and transferred to wheat cultivars with proven expression of tolerance in experimental trials. Triticum dicoccoides and Hordeum spontaneum, the progenitors of cultivated wheat and barley, have adapted to a broad range of environments and developed rich genetic diversities for drought and salt tolerances. Drought- and salt-tolerant genes and quantitative trait loci (QTLs) have been identified in T. dicoccoides and H. spontaneum and have great potential in wheat and barley improvement. Advanced backcross QTL analysis, the introgression libraries based on wild wheat and wild barley as donors, and positional cloning of natural QTLs will play prevailing roles in elucidating the molecular control of drought and salt tolerance. Combining tolerant genes and QTLs in crop breeding programs aimed at improving tolerance to drought and salinity will be achieved within a multidisciplinary context. Wild genetic resistances to drought and salinity will be shifted in the future from field experiments to the farmer.