American Chestnut Foundation Abandons Darling 58

The American Chestnut Foundation (TACF) says it will discontinue its development of the Darling 58 American chestnut due to significant performance limitations that, from TACF’s perspective, make it unsuitable as a restoration tree.

Likewise, TACF is also withdrawing its support for several pending regulatory petitions that would authorize distribution of transgenic Darling trees outside permitted research plots.

Throughout 2023, TACF and its partners observed disappointing performance results from broad scale field and greenhouse tests of advanced-generation Darling trees across several different geographic locations at external testing facilities. An analysis indicated striking variability in Darling trees’ blight tolerance, significant losses in growth competitiveness, and increased mortality, according to the foundation.

“Within the past few weeks, academic colleagues brought to our attention their newest findings suggesting a significant identity error in the propagation materials supplied to TACF,” William Pitt, TACF’s President & CEO, said in a statement. “Independent confirmation now shows all pollen and trees used for this research was derived not from Darling 58, but from a different prototype, one which contains a deletion in a known gene.

“That deletion, along with the discouraging field performance collectively renders these trees, in TACF’s opinion, unsuitable as the basis for species restoration. Fortunately, we have newer and better-performing trees ready to test.”

For more, visit tacf.org.