Author Topic: Pod defensive coloration (Caterpillar Mimicry) in the genus Pisum  (Read 490 times)

Andrew Barney

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https://www.researchgate.net/publication/275414737_Pod_and_seed_defensive_coloration_camouflage_and_mimicry_in_the_genus_Pisum

https://link.springer.com/chapter/10.1007/978-3-319-42096-7_56


Interesting pod coloration in peas. I discovered this article with interesting caterpillar mimicry on pea pods after i learned that Pisum elatius and Pisum humile are conspecific with Pisum sativum. This may mean that crosses between P. sativum and these other two species may be relatively easy. With the new discovery that these species have interesting pod colors / patterns I am now highly interested in doing some crossing experiments with them.

Quote
Ben-Ze'ev and Zohary (1973)  who concluded that P. elatius and P. humile were conspecific with
 P. sativum. P. fulvum produced shrivelled hybrid seed with P. sativum while the
 reciprocal cross produced stunted and abnormal seedlings. Gritton and Wierz-
 bicka (1975) have carried out an embryological study of the intergeneric cross
 Pisum sativum x Vicia faba.

Andrew Barney

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So far I have not had luck with contact of the articles authors as they no longer had seed and they were not from a seed bank but instead were collected from the wild.

However the JIC SeedStor had several germplasm accessions which mention pod anthocyanin spots or stripes on top of green pod color.

JI1075
JI1794
JI1795
JI1854
JI2115
JI2695
JI2698
JI3149
JI3151
JI3155

Garrett Schantz

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Another note in there as well: "The mature pods of P. fulvum are also defended in many inflorescences by degenerated flowers that develop into sharp thorns. It seems that this species is still in the process of evolving this mechanical defense as the response to millennia of strong grazing pressure." Interesting trait...
 From what I can tell, the crosses between these species can be diffucult depending on the accession. Fertility and vigor can be pretty low as well in the F1s.
 Some nice information on breeding between the wild species. https://link.springer.com/article/10.1007/s10722-018-0714-6
 There are even more by the same publisher here https://link.springer.com/search?dc.creator=%22O.%20E.+Kosterin%22
 JI1794 seems like a good one to attempt crosses with the other species, one of the articles mentioned F1 offspring from it did pretty well. Searching the accession online, it has been used quite a bit for breeding purposes.
 Not everything seems to agree on these being subspecies like the JIC Seedstor has some listed as. Lowered fertility in crosses, to me would say that these may not be subspecies as well. Being in the same genus they just probably cross relatively easily.
 Another fun link here. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6265838/
 Good luck with the breeding. 
 Pisum elatius and Pisum humile in particular are odd. Some are closely related to sativum, and some have difficulties crossing.
« Last Edit: 2020-10-14, 12:20:24 AM by Garrett Schantz »

Andrew Barney

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Thanks Garret. Yeah, from what a few have told me Pisum fulvum are very hard to cross with Pisum sativum (at least maintaining fertility). Pisum Elatius and Pisum humile are much closer related, and while there still may be some variable fertility issues possibly they both should still be more easily crossed than fulvum. From what i'm told Pisum humile is the closest relative. It seems from this tree Pisum elatius is both close and far, which i find interesting.

I now have a few seeds for the accessions i mentioned above. I requested them from the JIC and imported them using a proper USDA small seed lots permit. I also received some seeds from the professor in Israel, most notably a gift F2 hybrid between "Alaska" pea and Pisum elatius.

He had this to say about the seeds he sent me:
Quote
Two (red paper) bags contain seeds that were harvested from wild pea plants at two sites in northern Israel as follows:
1] Keziv creek (western Galilee)
2] Amud creek (eastern Galilee)

The third (brown paper) bag contains F2 seeds harvested from an F1 plant between cv. Alaska and a wild P. elatius accession. Not sure about the fertility level you will observe. I suppose that the two parents differ in a reciprocal translocation and therefore are expected to show a range of pollen (and egg cells) viability level.
« Last Edit: 2020-12-03, 09:03:18 PM by Andrew Barney »

Garrett Schantz

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Wonder if the F2 would be good breeding material for crossing todifferent species.

Andrew Barney

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Wonder if the F2 would be good breeding material for crossing todifferent species.

Maybe.

It also might be worth growing out in its own right. Anyone interested in [cultivated pea  x Pisum elatius] hybrids? Joseph, interested in possible weevil resistance?

If I remember correctly one idea for the ones with defensive mimicry may have nothing to do with Caterpillar mimicry but with weevil damage mimicry to escape weevil eggs. But there may be other weevil resistance strategies.
« Last Edit: 2020-12-05, 11:42:55 AM by Andrew Barney »

Klaus Brugger

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Very cool thread, thank you Andrew!

I wonder if the astriatus trait (Astr) conferring "short purple-violet longitudinal stripes" (http://data.jic.ac.uk/pgene/Default.asp?ID=64) is basically what we see on the pictures B and C of Pisum fulvum here.
Accession PIS 7608 of IPK Gatersleben that has "Astr" specified is a P. fulvum mutant (https://gbis.ipk-gatersleben.de/gbis2i/faces/pages/detail.jsf?akzessionId=26408).

Andrew Barney

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Very cool thread, thank you Andrew!

I wonder if the astriatus trait (Astr) conferring "short purple-violet longitudinal stripes" (http://data.jic.ac.uk/pgene/Default.asp?ID=64) is basically what we see on the pictures B and C of Pisum fulvum here.
Accession PIS 7608 of IPK Gatersleben that has "Astr" specified is a P. fulvum mutant (https://gbis.ipk-gatersleben.de/gbis2i/faces/pages/detail.jsf?akzessionId=26408).

Thanks Klaus,

I suspect that it is. I was thinking the exact same thing when I saw it. Though I've never actually seen it on Pisum fulvum, I suspect it is the same (or very similar).

Gene Tyle

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Just some stray comments...
I know Siamese cat pigmentation has a lot to do with heat loss (darker / tail & ears).
I saw some colorations that may be thermally influenced in the seed-pod pictures.
Any time you can make the pod distinctive from the foliage you make it easier for YOU to find and PICK.
I haven't a clue if would help the plant on its own or if our involvement is needed in the mix of things.

Steph S

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Interesting that the spots function as defense.
I grew Swedish Red this year, and they have caterpillar-like pods.  Also as the peas mature and the pods turn straw colored, the red of the seeds shows through because the pods are very thin.  Even I saw some pods that bursted slightly from the growing peas.  I guess the 'defensive' thing would be the color showing through.   I went through my photos which are not very good unfortunately and I don't seem to have gotten a pic of that.   My pic of harvested pods was indoors at night so they just look dark, but you can see how caterpillar-like they become as the seeds swell.   In my notes I called this "crinkly pod" but have no idea what the proper name of the trait would be.  ? Any idea?
I was pretty fascinated by the difference in pod traits of three 'drying peas' I grew this year.   Amplissimo had 'ordinary' pods with an average shape and average investment in structure.  Moose took a big chomp out of them.   Swedish Red seemed to make the most minimal investment in pod.  Very thin wall, and as you can see, the seeds bulge it out and make these caterpillar-like shapes as they mature.   Bulroyd Bean was the latest one, and the biggest investment in pod structure.  Very thick juicy pods, which you could tell held enough nutrients and moisture to continue to nourish the peas if cut off from the plant source.   I actually had to pick them green-mature to dry down, because some animal was getting to them as soon as they were fully ripe on the vine, and leaving the torn pods empty.  I was amazed how hardy these were, continuing to grow their last pods right into november and through a number of frosts.  I don't know if Swedish Red appearance did deter predators, but it was the one of three in this bed that had no trouble with any.



Andrew Barney

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Re: Pod defensive coloration (Caterpillar Mimicry) in the genus Pisum
« Reply #10 on: 2021-01-02, 03:13:07 PM »
Interesting that the spots function as defense.
I grew Swedish Red this year, and they have caterpillar-like pods.  Also as the peas mature and the pods turn straw colored, the red of the seeds shows through because the pods are very thin.  Even I saw some pods that bursted slightly from the growing peas.  I guess the 'defensive' thing would be the color showing through.   I went through my photos which are not very good unfortunately and I don't seem to have gotten a pic of that.   My pic of harvested pods was indoors at night so they just look dark, but you can see how caterpillar-like they become as the seeds swell.   In my notes I called this "crinkly pod" but have no idea what the proper name of the trait would be.  ? Any idea?
I was pretty fascinated by the difference in pod traits of three 'drying peas' I grew this year.   Amplissimo had 'ordinary' pods with an average shape and average investment in structure.  Moose took a big chomp out of them.   Swedish Red seemed to make the most minimal investment in pod.  Very thin wall, and as you can see, the seeds bulge it out and make these caterpillar-like shapes as they mature.   Bulroyd Bean was the latest one, and the biggest investment in pod structure.  Very thick juicy pods, which you could tell held enough nutrients and moisture to continue to nourish the peas if cut off from the plant source.   I actually had to pick them green-mature to dry down, because some animal was getting to them as soon as they were fully ripe on the vine, and leaving the torn pods empty.  I was amazed how hardy these were, continuing to grow their last pods right into november and through a number of frosts.  I don't know if Swedish Red appearance did deter predators, but it was the one of three in this bed that had no trouble with any.

'Biskopens Graert' (Bishop's Greypea) (Aka. 'Sweedish Red') is indeed an interesting variety. It's funny you mention it, because from memory i seem to recall it having very leathery pods (or at least a strong string), but now that you mention it, it does seem to often have what i just call the "constricted pod gene". If that is true, then perhaps it has either "n" or "v", one of the two genes that confer low-fiber edible pods (and better if you have both). I guess i never found them tasty as Biskopens is such a starchy pea (not even a good soup pea) that one would probably never want to eat them in the pod. I tried a few years ago to make greypea soup with them and even that failed (I suspect i needed to soak them much much longer). This is the recipie i tried to use from Toad / Soren: https://toads.wordpress.com/2008/10/28/grey-peas/

I actually have many Biskopens (Sweedish Red) Hybrids now that I would like grown out. I believe many of them are Umbellatum / Crown Pea types with purple pods. I was hoping many years ago to combine the unique red seed coat color with a more tasty edible pea. I think one the most wrinkled seed i got back from Canada was a cross between biskopens and Dwarf Grey Sugar (a selection of Dwarf Grey Sugar that i had selected for the constricted pod gene already).

Often the ones with constricted pods also have what Joseph likes to call the "pulverize to dust" trait which i believe signifies they have both the n and v genes for low-fibre. These are the ones that make the best snow peas in my opinion. Dwarf Grey Sugar (my selection), and Green Beauty are a few of my favorites that i think also have this trait.



"large podded" (either Green Beauty, Carouby de Maussane, or Bijou)



next 3 are Biskopens Graert (Aka. Sweedish Red):








Golden Sweet:

« Last Edit: 2021-01-02, 03:31:57 PM by Andrew Barney »

Andrew Barney

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Re: Pod defensive coloration (Caterpillar Mimicry) in the genus Pisum
« Reply #11 on: 2021-01-02, 03:22:50 PM »
Interesting that the spots function as defense.
I grew Swedish Red this year, and they have caterpillar-like pods.  Also as the peas mature and the pods turn straw colored, the red of the seeds shows through because the pods are very thin.  Even I saw some pods that bursted slightly from the growing peas.  I guess the 'defensive' thing would be the color showing through.   I went through my photos which are not very good unfortunately and I don't seem to have gotten a pic of that.   My pic of harvested pods was indoors at night so they just look dark, but you can see how caterpillar-like they become as the seeds swell.   In my notes I called this "crinkly pod" but have no idea what the proper name of the trait would be.  ? Any idea?
I was pretty fascinated by the difference in pod traits of three 'drying peas' I grew this year.   Amplissimo had 'ordinary' pods with an average shape and average investment in structure.  Moose took a big chomp out of them.   Swedish Red seemed to make the most minimal investment in pod.  Very thin wall, and as you can see, the seeds bulge it out and make these caterpillar-like shapes as they mature.   Bulroyd Bean was the latest one, and the biggest investment in pod structure.  Very thick juicy pods, which you could tell held enough nutrients and moisture to continue to nourish the peas if cut off from the plant source.   I actually had to pick them green-mature to dry down, because some animal was getting to them as soon as they were fully ripe on the vine, and leaving the torn pods empty.  I was amazed how hardy these were, continuing to grow their last pods right into november and through a number of frosts.  I don't know if Swedish Red appearance did deter predators, but it was the one of three in this bed that had no trouble with any.

Yeah, i'm not sure if the pod spots are actually defensive or if that was just a "best guess". It is possible they have not helped them survive at all and it is just random mutation. But i do think it would be very cool if it did help them either not get eaten by goats or eggs from pea weevils.

I have seen the red color of the peas of Biskopens (Sweedish Red) like you have mentioned, but i think that is just coincidence. I have seen a pod with light pink spots like in the paper once from my crossed lines, but it was very faint and hardly noticeable and faded as the season progressed with the heat (as anthocyanins often do). Still would be cool to fix as a trait in domesticated peas just for fun though. Bonus points if it helps deter weevils or deer.

Many have argued that Sugar Magnolia is not a true snap pea as it does not have the thick juicy pods like you described in that one shelling pea line. I also do not think it is a true snap pea, but more of a half-snap. So it is very interesting that pods can have all sorts of different traits.

I suspect the starchiness of the Sweedish Red peas is what deterred the animals which preferred juicy more sugary and tasty peas.

Andrew Barney

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Re: Pod defensive coloration (Caterpillar Mimicry) in the genus Pisum
« Reply #12 on: 2021-01-02, 03:28:47 PM »
and since we have now ventured into pea genetics in regard to pods for good snow / snap peas for the n and v genes, here is a nice photo that shows how to identify what genes your pea lines have or don't have. I think Templeton from AU said you can use a blue stain to show where the fiber is.

https://openwetware.org/wiki/Pea_Database_Collaboration_Project/Pea_Genetics


Andrew Barney

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Re: Pod defensive coloration (Caterpillar Mimicry) in the genus Pisum
« Reply #13 on: 2021-01-02, 03:36:00 PM »
Just some stray comments...
I know Siamese cat pigmentation has a lot to do with heat loss (darker / tail & ears).
I saw some colorations that may be thermally influenced in the seed-pod pictures.
Any time you can make the pod distinctive from the foliage you make it easier for YOU to find and PICK.
I haven't a clue if would help the plant on its own or if our involvement is needed in the mix of things.

Thanks Gene, Yes when it comes time to eat or save seeds it is sooo much easier having pea pods that are NOT green. Yellow is my favorite for standing out, but often the yellow color fades as the season ends, so purple pods are often easier for seed saving and eating. The downside is that it might make them easier to find for predators or animals as well.

Steph S

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Re: Pod defensive coloration (Caterpillar Mimicry) in the genus Pisum
« Reply #14 on: 2021-01-02, 05:16:38 PM »
Very helpful information about the traits, Andrew.  Thanks!
I did have a few Amplissimo with the 'constricted pod' trait but ordinary yellow peas - I wondered if it was a cross with the Swedish Red since they were from the same source. But it makes no sense genetically, for the constricted pod to show up with a yellow pea - unless they were crossed generations back.
Good to know about the starch test as well - that is potassium iodide I believe.  I saw the graphic for the traits at your website but did not understand that the dark spots were starch areas associated with the genes.  Very cool! 
I'll be disappointed if Swedish Red turns out not to make a good winter pea.   Are there other 'soup peas' that you like, or not a fan of it?