Evolution and origin of bread wheat.

Area of Science:

• Plant genetics
• Evolutionary biology
• Agricultural science

Background:

• Bread wheat (Triticum aestivum) is a young hexaploid species, approximately 8,500-9,000 years old.
• It originated from hybridization between a tetraploid progenitor (BBAA) and Aegilops tauschii (D subgenome donor).
• Rapid global expansion followed its formation, establishing it as a human staple food.

Purpose of the Study:

• To discuss the origin of bread wheat's diploid and tetraploid progenitors.
• To explore conflicting evidence regarding its formation location and tetraploid progenitor.
• To highlight the role of allopolyploidy in wheat's adaptation and expansion.

Main Methods:

• Analysis of new genome sequences to identify the B subgenome donor.
• Review of genetic and archaeological evidence concerning wheat's origin.
• Discussion of evolutionary adaptations to environmental changes.

Main Results:

• New genome data suggest the B subgenome donor is a distinct, possibly extinct, species.
• Evidence on the exact origin and tetraploid progenitor remains debated.
• Allopolyploidy likely facilitated rapid adaptation, trait acquisition, and mutation buffering.

Conclusions:

• Conserving the diverse gene pool of wheat is essential for future food security.
• Further research is needed to resolve progenitor origins and understand adaptation mechanisms.
• Wheat's evolutionary history provides insights into adapting to current climate change.