Evolution of wild emmer wheat and crop improvement

Allotetraploid wild emmer wheat, Triticum dicoccoides (TD) 2n = 28, the progenitor of most cultivated bread wheat, is an ecological specialist and excellent model organism for advancing evolutionary theory, wheat evolution, and wheat improvement. The center of origin and diversity of TD is northeastern Upper Galilee and the Golan. Elsewhere in the Fertile Crescent, it occurs in semi-isolated and isolated populations. The genetic structure is generally an "archipelago." Regional and local genetic patterns are partly or largely adaptive at the protein and DNA levels, both at coding and noncoding genomes, correlated with and predictable by environmental abiotic and biotic stresses. TD is a rich, mostly untapped, genetic resource for improving cultivated wheat, harboring drought, salt, mineral, and disease resistances, grain proteins, and with high variation in photosynthetic yield. TD was chromosomally mapped with 549 molecular markers and 70 QTLs for 11 traits of agricultural importance and domestication. Prospects include sequencing its genome; including 80% repeat elements for structural, functional, and regulatory polymorphisms, epigenetics, and genetic resources for wheat improvement. TD is affected by global warming both phenotypically (advancing flowering time) and genotypically (genetic erosion, SSR allelic turn-over, and novel drought resistant alleles). Hence, it should be conserved in situ and ex situ, to safeguard the arguably best source for wheat improvement and future food production in an exploding world population.