nitrogen fixing corn

[jocelyn]

I saw this on Science daily, and thought of you guys.

www.sciencedaily.com/releases/2018/08/180807144941.htm

[walt]

Thanks for posting this link.

I remember, however, back in 1977, In a Applied Plant Breeding course at Kansas State University, Dr. Nickle telling us that a corn breeder in Argentina publishing that she had found N fixation in corn in Argentina.  There was a brief flurry of excitement as USA breeders checked her work, tried to replicate.  They couldn't.
So she sent samples of the bacteria from the roots of the Argentinian corn.  Northern corn breeders tried again to replicate her work, and failed.
So she sent samples of the corn variety she had used.  Sure enough, the bacteria on its roots did fix N from the air.  
Dr Nickle said the same could be found on "un-improved" varieties from the USA, but selection for high yield with high N fertilizer had selected against corn that shed sugar to feed the bacteria that fixed N.
So it has been found again, and breeders are amazed again, and I expect it will be forgotten again.  I wish it wouldn't be, but history repeats.

By the way, Dr. Laura Jackson found N fixation by eastern gama grass back in 1983 or 1984.  Eastern gama grass Tripsacum, is Zea's closest relative

[raymondo]

We are a forgetting species. We may have forgotten already much more than we currently think we know. I’m pretty sure I have, though that’s a different type of forgetting methinks! N fixation, of one form or another, is probably widespread in the plant world. It needn’t be as intimate an arrangement as that between legumes and rhizobia which is what western science became fixated on. Fascinating stuff and I think walt is right. We have bred modern cultivars away from this sort of interaction. A group of local farmers who are exploring multispecies green manures and cover crops have found it better to use much older cultivars to increase soil biological diversity. The modern ones, they have found, just don’t seem interested in interacting with the micro world around them.

[steev]

That would make sense, as the modern cultivars have been bred to be artificially supported, rather than ecologically; it's much the same with many humans.

[jocelyn]

Yah, with high input agriculture, stuff gets lost. There is a metabolic cost to shedding sugars, but in nitrogen poor soils, it works.
I have one potato plant that the beetles don't like. I have let the bugs eat them pretty heavily this year, so it showed up.
Today is pick and squish day, but now I know which plant to mark and save seeds from. It was an accidental discovery, as Hubby rolled his truck,
and I was visiting him in the hospital till he got out. The garden got short shrift. Still, where there is difference, selection is possible, grin.
Hubby is OK now.

[philagardener]

Glad your husband sounds OK and you can get back into the garden!

[nathanp]

This appears to be the originating paper

link

There are several local varieties mentioned, that all have this trait. Rojo, Piedra Blanca, and Llano
It would be interesting to see if other areas also grow those.

[walt]

Nathanp.  Thanks for the link.
This paper discribes N fixing by nitrogen-fixing endophyte.  What was discovered back around 1977 in Argentina was done by rhizosphere bacteria.  So corn is now known to have 2 pathways to N fixation.  Neither have been used by modern breeders.

For those not familiar with the terms, rhizosphere is a mucilage sheath around underground roots.
Endophytes are microorganisms living between cells in plants.  I had first heard of them in fescue grass, where they give fescue resistance to various insects and diseases.  Breeders of lawn and golf course fescue love them.  Breeders of pasture fescue hate them because cattle grazing on fescue with endophytes get "fescue foot" which is very bad.  This paper is the first I've seen mention endophytes fixing N.

I'm going to have to re-read this paper a couple more times and look up the references.  There is more here than I can get from one reading.

Actually I think the comment on endophytes fixing N  was not part of the new research.  Maybe there are 3 ways now known for corn to fix N.  Must re-read.

[nathanp]

I also ran across this article while I was looking for the other one I posted.
link.springer.com/chapter/10.1007/978-94-011-3486-6_58

[steev]

Well, walt, isn't research a wonderful thing?

[walt]

Especially when others are doing it for us.

Don't get me wrong, doing research is fun too.  A couple of times I was present when, after years of work, the data was put into a computer and the statistics were calculated.  Jobs were on the line, though not mine.  But more important egos were on the line, people had made predictions.  It was time to know if something was true or not.  Something that had never been known before would finally be known.  (And maybe later forgotten.)  And I was there! 

And here in this forum, I see the same thing.  Exiting, isn't it!

[reed]

Anyone have any luck tracking down a source for the Sierra Mixe corn?

[nathanp]

Aug 16, 2018 10:16:02 GMT -5 reed said:

Anyone have any luck tracking down a source for the Sierra Mixe corn?

Actually, this trait may be more common than we are assuming, though it probably has been overlooked. I've seen a few pictures on Facebook recently of corn plants showing the aerial roots with mucus like liquids dripping. Joseph Lofthouse was one who went looking for the trait and found it. What would remain to be seen is whether it is fixing nitrogen like the bacteria mentioned in the study.

[Joseph Lofthouse]

Aug 17, 2018 23:24:58 GMT -5 nathanp said:

What would remain to be seen is whether it is fixing nitrogen like the bacteria mentioned in the study.

Hmm... I wonder if the nitrogen in the mucus is of a type and concentration that would show up in a soil test kit that can be bought at most any garden store?

[reed]

A plant helping to provide for it's own nitrogen sounds great but it just occurred to me to wonder, how much extra water might it take to drip that mucus? There are times around here when leaking water would be a very bad thing.