A recent international study has revealed how bread wheat played a crucial role in transforming the ancient world, leading to its establishment as a staple crop that now supports a global population of eight billion people. Researchers from the Open Wild Wheat Consortium (OWWC) have found that the genetic diversity of a wild grass called Aegilops tauschii was instrumental in bread wheat’s success. This grass provided the D-genome for bread wheat when it crossed with early cultivated pasta wheat, eventually leading to an agricultural revolution around eight to eleven thousand years ago. The resulting hybridization created a dynamic new crop with high gluten content that allowed for the production of airier, elastic bread dough.
Despite bread wheat’s genetic bottleneck effect and its self-pollinating nature, which should have limited its geographical spread beyond its origins in the Fertile Crescent, it became widely adopted across various regions. To understand how this rapid global expansion occurred, researchers created a diversity panel of 493 unique accessions of Aegilops tauschii, spanning from north-western Turkey to eastern China. By analyzing this genetic diversity, scientists identified that around 75% of the bread wheat D-genome is derived from the lineage originating from the southern Caspian Sea. This influx of genetic material from different lineages of tauschii has been essential in defining the success and adaptability of bread wheat as a globally dominant crop.
Further investigations have revealed a distinct Aegilops tauschii lineage, known as L3, which is geographically limited to present-day Georgia in the Caucasus region. This specific lineage has contributed the best-known gene for dough quality to bread wheat. By analyzing data from CIMMYT wheat landraces, researchers found that landraces collected from the Georgian region contained a higher proportion of L3 introgressions in the genome compared to those collected from the Fertile Crescent. This finding supports the hypothesis of historic introgression events that have influenced the genetic makeup of bread wheat and highlights the importance of different Aegilops tauschii lineages in shaping the success of bread wheat as a global crop.
In addition to addressing biological mysteries related to bread wheat’s genetic origins, the study has also provided valuable resources for researchers and breeders. The newly developed Aegilops tauschii open-source Pangenome and germplasm made available by the OWWC are being utilized worldwide to identify new disease resistance genes and climate-resilient traits that can be incorporated into elite wheat cultivars. These resources enable scientists to develop wheat varieties that are better equipped to combat agricultural challenges such as wheat rust and climate change. The collaboration between research institutions like the John Innes Centre and KAUST highlights the importance of maintaining genetic resources for breeding efforts that can enhance crop resilience and productivity.
By leveraging bioinformatic approaches and genetic analyses, researchers have shed light on the intricate dynamics of genetic introgressions in bread wheat derived from different Aegilops tauschii lineages. This collaborative effort has not only provided insights into the historical migration and hybridization events that shaped the genetic diversity of bread wheat but has also enabled the tracing of gene flow patterns that have contributed to its adaptability and success as a globally important crop. The study underscores the significance of preserving genetic resources and utilizing advanced genomic tools to improve crop breeding strategies and enhance food security in the face of evolving agricultural challenges.
