Andrew’s Pea Breeding Tips [2017]

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As homage to my older blog post about pea breeding information, which is an archived copy of my currently defunct website, i wanted to share a few tips and a pea breeding technique that i invented that helps increase the rate of pea crossbreeding success and produces a higher seed per pod ratio than standard “paintbrush” or “scalpel” crossbreeding techniques.

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Standard Pea Crossbreeding technique is one that i call the “paintbrush method”. It works, i guess. But i think I’ve found a better way. In the paintbrush or scalpel crossbreeding method you basically find the two pea flowers you want to use. First you select a closed immature flower as the female parent that you then use with a small pair of scissors (lefthand curved embroidery scissors work well for this) to remove all the pollen anthers before they have a chance to release mature pollen and self pollinate. Second, you then take an open mature pea flower to use as the male flower and use a paintbrush or scalpel to collect pollen and transfer it to the receptive style/stigma.

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Andrew’s Pea Crossing Method:

My method is a bit odd looking at first, but in my experience it works MUCH better. On average from what i can tell you usually get about 1-2 peas per pod with the “paintbrush method”. No more than 4. With my method i’d say you get on average of¬†4-5 peas per pod, with the potential of a whole pod 6-8 peas depending on your variety. So i’d say I’ve at least doubled the success rate, maybe even tripled it.

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First, i’d say get rid of that embroidery scissor. While it works, i find that a combination of pulling off the outer petals with your hands and using a small flat beveled or angled pair of tweezers works fantastically well. Get yourself a pair of tweezers like these. They may be referred to as “eyebrow tweezers”.

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Second, find yourself an immature pea flower to use as the female parent. Rip off all the outer petals and remove the immature anthers before it can self-pollinate. Third, find yourself an open mature flower for the male parent. Just cut or rip the whole flower off of the plant, we will need the whole thing. Fourth, use your tweezers to make a small opening in the bottom of the keel petal. Followed by slipping the flower used as the male over the stigma and style of the flower used as the female parent, making sure that the stigma/style gets covered in pollen at the top of the keel petal shown in the picture above. There is a small reservoir of pollen up there that makes for plenty of pollen to go around. Finally, leave this flower covering on there as long as possible. Sometimes they fall off, it helps to try pollinating the flower again during the next few days if this happens.

Why is this technique more successful?

Well, for me i think it’s a combination of things. First and most importantly it serves as a hood or covering for the flower to keep pollen from drying out or being washed away in the rain. In my climate the air can be quite dry and the high altitude with intense sunlight tends to wick away moisture quite easily. These tiny pea styles are quite delicate and seem to dry out so quickly that they can dry out before pollen has been able to set seed. Second, it provides a LOT of pollen over that whole style. I could be wrong, but i suspect that each of the receptive seed ovules mature at different times. If this is true, then it requires enough good pollen to be available over several days for each seed to be pollinated and grow. And finally, it just seems to mimic everything about how a pea flower would naturally self pollinate. Sometimes it’s best to just imitate nature as sometimes nature knows best.

How do you know what age of pea flower to use?

Good question. Here is a good illustration that should help. You need to catch a pea flower used as the female parent very very early actually. The pea flower second from the left is just about perfect because it is big enough to use but young enough it should not have released pollen and selfed yet. The open flower on the far right is about right for using as a pollen donor. If the pollen is too old or not enough, select a similar one that is slightly younger or try one that looks like the third one from the left.

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And that’s it. If you have any thoughts, please leave a comment. I hope you find it interesting and helpful. Happy Tinkering! ūüôā

http://daughterofthesoil.blogspot.com/2007/05/how-to-breed-your-own-garden-peas.html

8. Pea Breeding by Earl T. Gritton

http://daughterofthesoil.blogspot.com/2006/06/how-to-hybridise-garden-peas.html

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New Watermelon Breeding Project 2018 and Beyond…

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Today i’m sharing about a new plant breeding project i am planning on working on. The Watermelon Landrace project I’ve been developing for Northern Colorado has started to progress quite well and i am very pleased in the direction it is heading. This past summer of 2017 i harvested many that were of decent size, grew in my soil, and tasted excellent. I started to eliminate the ones that still develop blossom end rot and other poor traits such as funky shape or poor flavor. Starting to only save the best seeds.

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I originally added some Colorado Red-seeded Citron melons to my watermelon landrace because i wanted to breed watermelons with red seeds and frost tolerance. Citron Melons are supposed to be pretty damn hardy and supposedly have this desired frost tolerance. The problem? Citron melons aren’t exactly edible. They are not poisonous, just super hard white flesh and bland bland bland. Actually they are a very old heirloom type of watermelon called the Colorado Preserving Melon or the Colorado Red-seeded Citron. Apparently they have lots of natural pectin in them which is useful for making jams and jellies for toast. And did i mention they can breed quite easily with modern watermelons?

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When it comes to the Colorado Red-seeded citron i absolutely love their red seeds. I really want that trait in my watermelon landrace. I guess there are a few red seeded watermelon varieties out there already, but they are few and far between.

So, what happens when you breed a modern red or yellow fleshed watermelon with a citron melon? Well, i don’t exactly know. Yet. This year i planted a few of the red seeds i harvested from the citrons from last year that were mixed in with the landrace. The seeds i got were all still red so i figured they probably self pollinated. Regardless i added them to the landrace watermelon seed i planted this year in hopes that they would grow (not die), cross, and produce viable seed.

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I’m happy to report that so far that part of the project was a success. The top photo above shows what i think are confirmed F1 Citron x Watermelon hybrids. I suppose they could be F2, but i’m just going to assume F1. The seed was harvested from fruits that showed the characteristic “white cloverleaf striped mottling” that Citron Melons have, and from fruits that had hard white bland flesh when all the other watermelons had ripe yellow or red flesh. How do i know these seeds are hybrids? Well because the seeds were not red this time! In fact they were all different kinds of patterns and colors. Some red-black, some pure black, some greyish, some grey-black-mottled, etc.

Looking forward to growing this line of seeds out and reselecting for the traits i want. Red seeds would be awesome, but not necessary. Frost tolerance would be even more awesome, but not necessary. Even without those traits what impresses me most about Colorado Citron Melons is the fact that they grow so darn well in my climate, with my poor soil, and still grow full size melons even when over crowded with other watermelons that don’t do well, and even thrive with relatively low amounts of water. These traits alone are so very desirable to be folded into my watermelon landrace that this project is so exciting even now when i’m just beginning.

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I’ve heard a rumor that way back the Soviet Union (USSR) did lots of plant breeding experiments (maybe because of the breeding genius known as¬†Ivan Vladimirovich Michurin), and part of these experiments involved Wide Hybridization or Distant Hybridization, which means crazy breeding like interspecific, intergeneric, intrageneric, and intraspecific breeding and attempted crosses that most people would never try or attempt. Some of these crosses were successful. What i’m interested in is the Soviets work on Citron-Watermelon hybrids. Apparently they experimented with these long before i have and rumor has it that they were able to recover some nice tasting watermelons that were able to be stored for several months into the winter. Awesome. I will update this blog post when i have more information about this. There are already supposed “Winter Watermelons” that supposedly keep for several months, but i’m sure those can be improved, or i can just breed my own winter watermelon variety. Exciting stuff!

Edit Nov-15-2017:

Okay, so i finally received¬†a copy of the rare book titled “Wide hybridization of plants (Otdalennaya gibridizatsiya rastenii) Proceedings¬†of¬†the Conference on¬†Wide Hybridization of Plants¬†and Animals; collection¬†of¬†reports” from inter-library¬†loan. A mouthful, i know. Thanks to WorldCat to helping me track it down. Not many copies of it left around.

Originally¬†written and published in Russian in the U.S.S.R. in 1958, and Translated into English in Jerusalem Israel in 1962.¬†The Soviet Union was known in those times for great scientific advances including launching the space race, the first cosmonaut in space, Sputnik, and other crazy medical advances like the Skenar and Bacteriophage medicine, to strange sci-fi spy weapons in the Cold War. Apparently they also were advancing in novel plant breeding techniques¬†and programs. Michurin was one of these guy’s. If you’ve never heard of him or his plant breeding techniques¬†and success go look him up. I honestly don’t know much about him myself, but i do know he was an accomplished plant breeder, most notably with wide genetic crosses that noone else thought would work.

Anyway, back to the Interspecific Hybridization of Watermelon work done by the Russians with Citron x Watermelon crosses in 1958. Turns out they did have success with it. The F1 generation¬†was mostly like the wild Citron with bland hard tasteless flesh. F1 and F2 Hybrids with¬†Citrullus colocynthoides are similar to their wild Citron parent genetics. Late-ripening, coarse compact unsweet fruit pulp and a thick rind. Quite unremarkable. But that’s what i was already expecting. One cool note though is that some of these in future segregating generations or backcrosses to domestic watermelons can produce some sweet watermelons that have some storage ability. Meaning they ship well and can store for many months. In fact some of them get sweeter over time whereas¬†domestic watermelons do not. So all in all some cool potential in the project after all! I’m even more excited now!

If you want to read the Soviet’s 1958 watermelon research yourself, i have taken the effort to scan some of the book into a PDF for you. It’s not the whole book, but it has the relevant chapter on Watermelon and Citron crosses.

Here’s the PDF:¬†Wide_hybridization_in_plants_TSITSIN

Improving the Tomato Genome by breeding with wild tomatoes [2017]

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Solanum peruvianum (wild tomato with desert tolerance)

So i haven’t written a blog post in some time. Sorry about that. It has been very hectic this year. That’s not to say that i’m completely dead. And despite my busyness and absence i am still dabbling a little bit in the garden and plant breeding scene. I didn’t have the time, energy, or space to work on my purple Indian Corn or Teosinte this year. I barely made room for beans, peas, tomatoes, and a row of watermelon.

The beans are my special four corners native beans which include, New Mexico Red Appaloosa (aka. Gila River bean), Anasazi, Zuni Gold, Rio Zape, and maybe a few others. The Peas are a large growout of my 17-23 different varieties of genetically unique and rare pea varieties, some of which are segregating crosses that i did two seasons ago. And tough i don’t have many pictures i will post one below of a purple podded umbellatum-type (aka. crown pea) where all the pods come out in a jumble all at once. To have a purple podded one of these is new and kind of cool. I hope to have a yellow and red-podded umbellatum-type pea someday. The watermelon are the result of mine and Joseph Lofthouse’s Watermelon Landrace project. Joseph Lofthouse seems to be world famous now for his widely successful landrace seed varieties and breeding techniques.

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Purple Podded Umbellatum Crown Pea

Anyway, back to the tomatoes. The Tomatoes are a brand new project and sort of an offshoot of one of Joseph’s new landrace breeding projects as well and a few other fellow collaborators and breeders as well. It all started when Joseph was working on wanting to convert tomatoes to a landrace like many of his other successful crops. But there are a number of problems with that and domestic tomatoes in general.

The first problem is that domestic tomatoes are entirely self pollinating and don’t outcross all that much and have tiny closed-up flowers. Another problem is that domestic tomato flowers are not very attractive to pollinators. And the third major problem is that domestic tomatoes went through several genetic bottleneck selection events when they were domesticated that they have a very narrow genetic base. This narrow genetic base means that 1. Most tomatoes are subject to easily succumbing to disease and 2. that when they do outcross there is not much variation anyway. An average bad-tasting disease susceptible red tomato that crosses with another¬†average bad-tasting disease susceptible red tomato means that in the end all you really get is more of the same.

My interest in all of this starts with the basic fact that in my climate here in Northern Colorado with my soil (mostly a dry clayish sandy soil where mostly desert plants grow), and the high altitude with intense sunlight and UV and the dry wind that wicks moisture out of the ground means that most garden varieties of anything don’t do all that well here unless intensely babied. This applies most especially to tomatoes. Even worse when it comes to Heirloom tomatoes. Sure heirloom tomatoes generally taste better, but to have a tomatoe plant produce like ONE good tomato through a whole season… That’s a MAJOR FAILURE in my book.

There are lots of tomato freaks out there that try to tell me that here in Colorado i can grow ANY tomato variety and be successful. And while that might be true if i replaces all my soil with compost or potting mix and provided massive amounts of water, and started them all early and planted them all out perfectly then yes maybe that would be true. But that’s not what i want to do, not should i have to do that. I should be able to just start a tomato plant and plant it where i want and not have to worry about it all that much and have it produce a decent harvest (whatever that happens to be). And not have to worry about disease, or growing slow, or not being adapted to my soil or the intense UV light or whatever. That’s where all this plant breeding comes in.

The goal(s): 

  • To breed a superior tomato variety that does well for me (in dry N. Colorado)
  • To increase the genetic diversity in the tomato genome by using wild tomatoes
  • To create or recreate a tomato that is highly attractive to pollinators
  • To create a population of tomatoes that are highly outcrossing
  • To create a tomato that i actually think tastes good and NOT like cardboard

.

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wild tomato seeds. photo courtesy of Joseph Lofthouse

This project is still in it’s early stage, but it is progressing nicely. On Joseph’s end he is having huge success by using wild tomatoes bred with domestic tomatoes that have large showy flowers with exerted stigmas and have lots of pollen available that make them attractive to bumblebees. He is using mostly Solanum habrochaites but is starting to branch out to other wild tomatoes as well. Others are working on breeding tomatoes that produce a good harvest in under 100 days from being direct seeded and that have frost tolerance.

On my end i am experimenting with as many wild tomatoes that i can. I am evaluating several accessions of wild Galapagos tomatoes which so far are not doing much. The S. habrochaites also are not doing much. The ones i am having excitement from are the Solanum peruvianum which have silvery leaves and desert tolerance (in the roots) and a F1 hybrid between a domestic tomato and Solanum pennellii which has a different form of desert tolerance (in the leaves). I am excited about these genetics since they seem to be growing very well in my garden. The largest of any of my tomatoes is this F1 hybrid of S. pennellii. It is HUGE!!

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F1 hybrid between domestic tomato and Solanum pennellii
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Flowers of an F1 hybrid between domestic tomato and Solanum pennellii
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F2 cross of domestic tomato and Solanum habrochaites

A Teosinte Christmas in Colorado

So, i know I’ve blogged a bit about experimentally growing Teosinte in¬†my post about growing prehistoric corn¬†and also in¬†my post about differences between teosinte species. Both posts have gotten quite a bit of traffic over the years and have brought people to my blog who are interested in Teosinte specifically.

For those of you who don’t know Teosinte is a progenitor to modern Corn (Also known as Maize), which is still able to interbreed with Corn. Some teosinte is annual, while others are perennial (or maybe bi-annual). There are many people who are interested in breeding perennial teosinte with corn to make perennial or bi-annual corn.

The major problem with trying to grow Teosinte in a moderate climate as here in Colorado in the United States is that it is adapted to grow in the climate of mexico and our growing season just isn’t really long enough. Even more so since Teosinte is day-length sensitive and does not even start to tassel, silk, and pollinate until the days get short and the sunlight shifts deeper into the red spectrum. By the time that happens here it is usually around August and often we get snow by September or October. Definitely not enough time for Teosinte or Corn seeds to mature and dry down for saving. …Or is it?!

Well, this year it just happened to turn out just barely long enough. I’m calling it my Christmas miracle! haha. I think it was a combination of it being a La Nina weather year with an unusually warm fall with no snow until here in December. But also with the fact that i dug up my clump of teosinte plants and put them in a pot in the garage. Though they were a bit unhappy in the garage and were touching the ceiling.

Still i was able to keep them in there long enough to hand pollinate them. But to be honest i thought i had again failed to get viable Teosinte seeds. But when the plants were dead i went out and happened to find some! Above is a picture of what i believe to be seeds of ‘Zea mexicana’ teosinte seeds.

If there is one moral of this story that you should take away it is this: Never give up even when everyone else thinks you are crazy or tell you that what you believe is impossible. I learned this in gardening from my friend Joseph Lofthouse of Utah. He has had success with so many of his unusual crops that no one else in his valley of Utah is able to grow. He often starts with many varieties of a plant as possible and grows as many as he can. Often more than 90% of them die or fail to produce seeds. But he only needs a few that do. Once he gets seeds he can start to effort to plant them year after year and adapt them to his climate. If they still fail to thrive he lets them die or culls them off himself. But he has a variety of unusual crops, such as Landrace Watermelon adapted to Utah (and by extension Colorado), Landrace Cantaloupe, Landrace inter-species hybrid squashes, Tomatoes that are self-incompatible and are highly attractive to bees (modern tomatoes are not at all and are highly inbred), and more.

 

On the left here is a photo of one small cob of a teosinte hybrid (zea diploperennis-corn hybrid from the USDA) pollinated with what i believe to be flour or field corn pollen. On the right is the same teosinte-corn hybrid cob line but i believe this one was self pollinated with its own pollen. It seems to have popcorn heritage as the seeds show popcorn / flint corn characteristics.

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Here is another strain of day-length neutral teosinte (decended from Zea mexicana) that a collaborator Joseph Lofthouse of Utah is growing and having success with. I believe he got the seed originally from NativeseedsSEARCH in Arizona. He decided to test if it makes good popcorn.

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Here is my Teosinte clump in the summer of 2016.

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Here is the same spot with snow on it now in winter.

If you’d like to follow the discussion about growing teosinte in places it is not normally supposed to grow (or other unusual crops) then visit the Alan Bishop Homegrown Goodness plant breeding forum here!

Orange, Yellow, and Red-podded peas.. oh my!

Sorry for not posting anything about plant breeding lately. I’ve been rather busy this year. But i still have a few plant breeding projects (mostly from last year) that i dedicated garden space this year ¬†for. These include my Colorado bred / adapted Watermelon Landrace, which did quite well last year (even a racoon thought so and ate one that was overripe). My Wild Pueblo squash from Utah. An attempt at a sweet potato growing / breeding project. A mass tomato growout / trial. Some perennial teosinte-maize hybrids. And my various pea variety growouts which includes: Salmon-flowered pea and crosses, mummy-white and crosses, mummy-pea, Biskopens and hoped crosses, Joseph’s red-podded peas, Joseph’s yellow podded peas, Orange-pod, Virescens Mutante, Sugar Magnolia, Sugaree, Green Beauty, Purple Passion, Dwarf Grey Sugar, Spring Rose, Canoe, Mighty Midget. I also finally made one successful cross this year between Mighty Midget and Purple Passion. That should eventually give me a super dwarf with purple seeds and also improve purple passion to have stronger stems as it’s normally a very spindly plant.

This winter, i think in February i ¬†experimented with making a small cold-frame and using it to plant some of my peas super early. You can see it here where i watered it with snow and then a few weeks later the pea seedlings emerging but it still being rather cold outside. It worked great though. This particular cold frame is more suited for super dwarf or extra dwarf peas or lettuce or something. If i had a greenhouse i’d totally experiment more with growing vegetables in the winter.

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A nice segregating yellow pod from the red-podded breeding line. Very nice.

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A nice yellow and red mottled pea pod. The contrast is what makes this one really stand out! A line to keep an eye on for sure.

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A remnant from Dan Quickert’s purple snow pea project. This is one of the few that didn’t die off a few years back, so this one must have had much better genetics than it’s siblings. A nice example of a purple snow pea, which are still quite rare. This one is called ‘Midnight Snow’.

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And some of the orange-pod gene peas (orp) i’m growing from the Gatersleben gene bank. These have an interesting orange color on the inside of the pod. I hope to use these to make better yellows and better red podded peas in the future.

‘Wild Pueblo’ Squash Variety (2015)

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Wild Pueblo Squash, Loveland Colorado 2012

I feel somewhat bad that i haven’t done much with plant breeding posts or other projects like my homemade Taffy Machine, or chemistry. I had some of those projects listed on my website. Unfortunately my website has been neglected my me and is currently down and redirects here. Perhaps by next year i can work on it again. Until then, i will try my best to diversify my blog and post some of it here.

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This year i was able to grow some squash. In particular i was able to grow a few plants of my ‘Wild Pueblo’ Squash. Cucurbita maxima ‘Wild Pueblo’. Wild Pueblo is the name i have given it after both of our native pueblo ancestry. The woman who was kind enough to give me seeds was originally calling it Wild Hopi. But since i do not know if this is specifically a squash grown by the Hopi i decided to rename it. In any case it seems to be an Ancestral Puebloan variety of squash that is very old.

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Photo by Bobbi HolyOak, 2011, Moab Utah

In the past i never really cared that much about squash. Probably because i always had the attitude that all squash are the same. But, since I’ve been trying to find my own crops that are personal and thrive in my climate (even resorting to breeding some from scratch), I’ve decided that it would be incomplete without my own squash. In fact i think my squash are becoming my favorite thing to grow. I have a feeling that squash are¬†going to be my favorite crop. There is just something special about seeing a squash plant growing from seed. Almost sacred and special. It’s hard to explain. Corn has a similar effect on me, but even more so with squash.

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Wild Pueblo was originally recovered growing in the wild of southeast Utah somewhere around the Monticello area. Close to the famous Newspaper Rock historic site. It was said to be found off the beaten track growing behind an old somewhat hidden pueblo ruin. Next to the ruin was a small stream. Growing next to the stream was a large squash plant with several large ripe squash fruit.¬†I estimate that it is possible that it could have been growing undisturbed in that area for over 150 years! If so, this thing could have some awesome genetics. I’m doing my best to grow out the seed and preserve this variety.

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Wild Pueblo Squash, 2012
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Wild Pueblo Squash, 2012, Loveland Colorado
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Wild Pueblo Squash on the left. Hopi White Squash on the right.

I suspect Wild Pueblo is an older variety of squash which may be related to a landrace which may have been used to breed the variety called “lakota squash”. according to reports…

“The Lakota squash, a mid-1990’s open-pollinated introduction developed at the University of Nebraska by Dr. D. P. Coyne. Dr. Coyne experimented with crosses and selections to assure more uniform pigmentation of this beautiful squash before making it available to the trade.

Lakota squash was developed from seeds obtained by the University from Nebraska’s Fort Robinson, once a prairie Cavalry post, later an agricultural site, now a National Park. The variety it was derived from is no longer in cultivation. It had been grown by Native American peoples along the Missouri Valley for centuries before the arrival of Europeans to the continent. This indigenous squash was also cultivated by the troops stationed at Nebraska’s Forts Atkinson and Robinson, and by early Nebraska settlers.”

Edit: after talking to someone at the University of Nebraska who worked with Dr. Coyne with the original germplasm of the non-hubbard parent landrace of squash i am told the fruits were actually oblong. Still might be worth trying to grow out that accession of seed before it’s no longer viable and available… i will see if i can get some seed…

I have only grown this variety twice, but even so it has some incredible diversity which i find absolutely fascinating. In time i think i can do some great things with it, perhaps even selecting it to grow even better.

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Photo by Bobbi HolyOak, 2011, Moab Utah

This year was a very odd year to grow things. Perhaps the El Nino weather was to blame. I don’t know. All i can say is that my squash took all season to grow anything at all. I only got one plant that grew big and produced a large squash, the rest were small, but contained seeds. Next year i will try to plant more and do better.

Like i said before, it has a LOT of diverse genetics!

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All i can say for now is that it is good to be home.

Pea Breeding Resources

Pea Breeding is actually really awesome. Especially when you can get really neat colors to recombine into new combinations. Punnet Squares to predict the genetics of pea breeding is also very helpful and fun too. This page contains a multitude of information on pea genetics.

(This page was originally hosted on my test website Biolumo.com, but since i am hosting it myself on my own computer it is not exactly a reliable place, and hence i have copied all of the relevant information here to my blog as a permanent place to find it.)

Details of Mendel’s Pea Breeding

Here is a copy of Mendel’s original paper, for those who are interested.

biologyThe Results of Mendel's crosses for seven characters in pea plants

The following pea breeding illustrations were obtained from the Eighth Edition of Biology by Neil A. Campbell. I’ve scanned the relevant illustrations about pea breeding. If you would like to view¬†the genetics section in PDF form instead, then here you go:¬†You can read the whole genetics chapter in a virtual pdf online.

crossing pea plantsF1 Hybrid Pea Plants

Pea Alleles, Locuspeas F2 generation

random combination of the gametes results in the 3:1 ration that Mendel observed in the F2 generationMendel Pea TestcrossMendel Independent Assortment

—————————————————–

Rebsie Fairholm's Red-Podded Pea
Rebsie Fairholm’s Red-Podded Pea

If your still interested in pea breeding, then you might be interested in Rebsie Fairholm’s breeding projects involving peas. Not only is she breeding a very neat yellow sugar snap pea called¬†Luna Trick, but she is also breeding an awesome red-podded pea as well! She not only shares photos and info about her crosses on her blog, but she has also provided 2 excellent tutorials for crossing peas with photos! Many of us amateur plant breeders are attempting and making progress on recreating Rebsie’s red-podded pea success here.

Trying to figure out the gentics for this rare red-podded pea is facinationg! Here are my attemopts to figure it all out with punnett squares below.

Parent Generation (P)
F1 generation if purple-pod parent is homozygous for the purple gene

F1 yp yp
GP GyPp
purple pea
GyPp
purple pea
GP GyPp
purple pea
GyPp
purple pea
OR
F1 generation if purple-pod parent is heterozygous for the purple gene
F1 yp yp
GP GyPp
purple pea
GyPp
purple pea
Gp Gypp
green pea
Gypp
green pea

But as it turns out, Rebsie’s results actually had mostly green pods. And upon doing some research about the genes responsible for the purple-podded trait, we actually find that there may instead be 3 genes needed for the anthocyanins to be present. One gene commonly called “A” is a master swich gene and is epistatic to the other genes coding for anthocyanins. The other two genes are also both required for the pod to have purple-pod’s. If this is correct than that means the punnit squares i completed above are no where close to being accurate. Here is the F1 hypothesis again, and this one as far as i know is correct this time. I have used the letter “A” to represent the on/off gene, along with “P” and “U” to represent the two purple-pod genes. I have left out the yellow podded gene because all offspring will be hetozygous for a base pod color of yellow/green.

Here is the corrected F1 generation hypothesis using the three genes for purple anthocyanin colors. We are ignoring the gene for green/yellow pods for the moment since all offspring in the F1 generation are heterozygous for dominant green and recessive yellow.

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That gives us a ratio of 28 Purple : 36 Green.

So I guess Rebsie was right; in the F1 generation mostly green pods appear.

Here is the F2 Generation Hypothesis using the rule of independent assortment. Now this table is not entirely correct, but represents the “average” offspring collected from the purple-podded plants in the F1 generation. I say the average because in the best case scenario you can get purple-podded plants that be homozygous for ALL of the purple genes. On the other hand, the worst case scenario is that the purple-podded plants in the F1 will be heterozygous for ALL of the purple genes. In most cases though i think that the average purple-podded plant in the F1 will have two homozygous genes and the third gene will be heterozygous. In that case you would only need to worry about two sets of genes in the F2, nameley 1 set for anthocyanin and 1 set for yellow pods underneath.
screenshot-3-1
Which in this “average” scenario results in the typical 9:3:3:1 Phenotypic Ratio.
And in this case the red-podded peas are the recombinant offspring that we are loking for.
If we take that a little furthur, that means that if you plant 50 F2 generation seeds, you should get a ratio of about 43 non-red pods : 7 red-pods.

Inheritance Of The Colors Of Pea Flowers

Mendelian Inheritance Of The Colour OF The Flower In The Culinary Pea

Pea flowers (the edible kind) come in three major colors. They can come in the “wild” form which is a Bicolour Purple, White, or Salmon Pink (pink-and-white). I first encountered this information on Rebsie’s blog, and after doing some research of my own, i found one refrence to the same imformation in a very old book from 1912 (Breeding and the Mendelian discovery by A.D. Darbishire). The purple form is dominant and is a trait mostly common in field peas. The pink form is recessive to the the purple, but is dominant to the white. The white form is recessive to all color, and is commonly associated with modern peas that have been selected for high sugar content. It’s a bit amusing the way the book talks about the purple form in relation to the other two. Apparently if you breed the pink with the white you will get purple in the F1 generation because the pink has the gene that expresses color, but the white is actually hiding the gene for purple flowers. In the book this is talked about as an ancestral trait, a throwback, and the theory of reversion.

In Darwins book, The Origin of Species, Darwin himself encounters something similar with his breeding of pigeons. Darwin bred a pure white pigeon with another white pigeon (with black tail feathers), and was very surprised because in the next generation he got a blue pigeon (which has the same coloring as the wild rock pigeon). But Darwin didn’t know about genetics, so he could only conclude that it was a ancestral throwback phenomenon. We now know that the white one with black stripes had the gene for color (black) and the pure white pidgeon was actually a blue pidgeon but did not have any active color genes. To my knowlwdge the only variety of pea known to have pink flowers is the one called ‘Salmon-flowered’.

Salmon-flowered, pink, pink-and-white pea flower Bicolour Purple pea flower white pea flower