The claim regarding the emergence of bread wheat around 8,000 years ago in the South Caucasus via natural hybridization is mentioned in the context of the research (web search results 1 and 2), but the evidence provided is insufficient to confirm this specific claim across multiple independent sources. The evidence is heavily focused on the research findings, making it difficult to corroborate the specific details (8,000 years ago, natural hybridization) from multiple distinct, non-related sources.

The claim that the findings were published in PNAS and based on archaeological work by the Georgian National Museum at Gadachrili Gora and Shulaveris Gora is supported by multiple web search results referencing the study. However, the evidence provided does not include cross-references from multiple independent news organizations confirming this specific publication and institutional link, limiting the verdict to 'single_source' based on the provided evidence structure.

The specific detail that samples show evidence of early domesticated wheat crossing with *Aegilops tauschii* is a core finding of the research discussed in the web search results. While multiple sources reference the study, they do not independently corroborate this specific scientific finding (the crossing with *Aegilops tauschii*).