modern seed breeding making varieties that can't form symbiotic relationships with mycorrhizal fungi

I was listening to Gabe Brown when he threw out there that modern crop breeding is unwittingly producing seed varieties that have lost the ability to connect with mycorrhizal fungi...uggh.  When you think about how plants are grown and selected it makes sense that this would happen.  If plants are grown in environmental conditions that don't allow the microbial food web to function well then the cost of carrying an ability with no benefit will be selected against by the breeder over time as plants that don't bear that cost will do better and be selected for.  

This was discovered by soil scientist Dr. Wendy Taheri when looking at one corn variety's roots under a microscope.  She has since found other varieties of crops that can't do it either.  

Just throwing this out there as a cautionary tale.  This is another good thing to keep in mind when creating your landraces or when trying a method like no till.  

You definitely get what you select for. If you select for crops that only thrive when fertilized, or sprayed with chemicals, you might very well end up with crops that can't grow without fertilizers and poisons.

Joseph Lofthouse wrote:
You definitely get what you select for. If you select for crops that only thrive when fertilized, or sprayed with chemicals, you might very well end up with crops that can't grow without fertilizers and poisons.

This is especially true with fruit trees. It doesn't make sense that after decades of breeding, we still don't have Apples and Peaches that are not prone to diseases. There actually *are* some varieties that have natural immunity to disease. For example,  Frost, Indian Free, Muir, and Q-1-8 are all resistant to Peach Leaf Curl *. Yet, the majority of Peach varieties grown are still vulnerable to this disease... if a new peach variety gets peach leaf curl during the breeding, they just spray it with fungicides and carry on with the breeding program as if it's a non issue. Disease resistance usually comes at a cost in productivity, so they are actually breeding for disease prone trees when they do this and selecting against disease resistance.

* Source http://ipm.ucanr.edu/PMG/PESTNOTES/pn7426.html

Here's a link to an abstract of a research study that showed a big difference in resistance of sweet chestnut to ink disease when inoculated with mycorrhizae, versus no inoculation. It's not the same thing as breeding the connectivity out of the trees, but does demonstrate that the connection enhances the health of the tree (in addition to enhancing uptake of nutrients and water, and improving general soil condition, which I think are benefits that most people would already acknowledge - or at least people on this forum).

Effect of mycorrhizal fungi on chestnut ink disease

I think about this when large scale producers complain about heirloom seeds being poor performing. These producers are too used to growing plants that have been bread for what they see as an ideal condition more than what the plant may see as an ideal condition. It is scary to think about since large scale producers are moving the most seed around.

Hi Greg, that is really interesting... and a little disturbing. Do you have a link to the information about seed varieties that no longer connect to mycorrhizal fungi? I would love to read more about this issue.

Gilligan Caisse wrote:Hi Greg, that is really interesting... and a little disturbing. Do you have a link to the information about seed varieties that no longer connect to mycorrhizal fungi? I would love to read more about this issue.

I was hoping to find the same!  The searching I did didn't bring up a variety list.  It seems that Dr. Taheri was trying to offer her services to do testing for folks and that maybe that didn't work out as a business model.  My assumption is that the plant breeders that breed under conditions that generate such plants have a world view that doesn't allow them to appreciate this service.  Sadness.