Project 01

Pollen, controlled crosses & RGS

Connect the best large survivors, then let field data and genomic prediction help identify exceptional offspring.

Controlled pollination

Make the cross that nature cannot.

Large surviving American chestnuts are often miles apart. By collecting pollen and applying it to selected trees at Matthews, we can create families that would never form naturally.

We work with a network of chestnut enthusiasts who collect pollen from large survivors, and we collect pollen ourselves. Each sample is labeled, dried, stored, and used for carefully documented controlled pollinations at the Matthews orchard. The result is seed from exceptional survivors that may be separated by many miles or even by mountain ranges.

Why controlled pollination? It gives every nut a known mother and father. That pedigree lets researchers connect family performance and DNA profiles back to the parent trees.
Volunteer on a ladder making a controlled pollination in an American chestnut crown
Pollen source trees

Survivors worth connecting.

These large survivors contribute distinct American chestnut genetics to the breeding network. Pollen collection lets us connect them with selected orchard trees while preserving the identity of each parent.

Floyd 4 large surviving chestnut

Floyd 4

Large surviving American chestnut and pollen source.

Carrie Blaire 1 large surviving chestnut

Carrie Blaire 1

Large surviving American chestnut and pollen source.

Deane 1 large surviving chestnut

Deane 1

Another large survivor contributing to the wider network of breeding material.

Where the nuts go next

We support TACF's RGS program.

The nuts from each cross we create enter The American Chestnut Foundation’s recurrent genomic selection program. RGS links DNA profiles with measured disease responses so TACF can predict which related seedlings are most likely to carry superior resistance, then improve those predictions with each new round of field data.

Preserve the pedigree

Keep every nut tied to its known mother and pollen parent.

Grow the offspring

Germinate the controlled-cross nuts and collect tissue from the resulting seedlings.

Profile the DNA

Use genomic relationships to compare seedlings with trees whose disease responses have already been measured.

Predict resistance

Rank related seedlings for their likelihood of carrying stronger blight resistance.

Test and improve

Plant field trials, measure disease response, and feed the new results back into the model.

A vial of pollen can connect trees separated by mountains.

Collection, labeling, drying, shipment, and controlled pollination are all jobs where trained volunteers can make a direct scientific contribution.