Monday, July 3, 2017

Request for Ash Samaras for Embryogenic Cultures

Request for Ash Samaras for Embryogenic Cultures
Drs. Scott Merkle and Kamal Gandhi, University of Georgia

Our research team would like to greatly expand our collection of embryogenic cultures from seeds collected from surviving ash trees that have remained alive for at least five years since emerald ash borer (EAB)-induced dieback has been documented in an area.  Below are collection and shipping instructions for cooperators who have identified putatively EAB-tolerant female ash trees from which samaras can be collected.

We would like to get about 50-100 immature samaras per ash tree.  They need to be collected from the tree while they are still immature.  In Athens, Georgia, the stage of green ash seed (not fruit with wing) development that worked best was when seeds were 4-8 mm long and the zygotic embryos inside were 1-3 mm long.  Below are some photos showing the stages of seed and embryo development we tested some years ago.  In the seed photo, the best stages for culture initiation are in the middle of the distribution.  In the embryo photo, the shorter embryos were the best.  The best date for getting those stages here in northeastern Georgia was the third week of August.  The best collection date for white ash seeds in Michigan was the first few weeks of August.  You could dissect some of the samaras to check if the seeds and embryos are near these stages.  Samaras should be stored in zip-lock bags, with the name or code for the tree written on the bag in Sharpie.  Please try to get them into a cooler on cold packs as soon as possible after they are collected and store them in a refrigerator until shipped.  They can be shipped in a cooler on cold packs (cheap Styrofoam cooler in a cardboard box or insulated bag is fine).  FedX or UPS next day delivery would be best (can arrive anytime the next day—it does not need to be here by 10 AM).  We can supply our UPS account number, if needed.  They should be shipped to:

Dr. Scott Merkle
Warnell School of Forestry and Natural Resources
180 E. Green Street
University of Georgia
Athens, GA 30602

When you ship, please email the tracking number to  We have had some problems with UPS, and we don’t want the samaras to sit in some broiling warehouse for a day.  Also, please include information about the collection date(s), tree locations, and time since EAB detection/first report of dieback in the area.  Photographs of the crown of the surviving ash trees will be appreciated.

Green ash seed (left) and zygotic embryo (right) developmental stages.  Bar in each photo is 1 mm.