Following in Mendel’s Footsteps

…and discovering how interesting pea breeding can actually be…

Google’s logo showing a dihybrid cross, but failing to follow the law of independent assortment (yellow pods & yellow seeds are not linked), and also failing to show that yellow seeds are dominant. But, it does show the 3:1 ratio of green:yellow pods in the F2 generation.

After noticing that Google’s logo today was in honor of Gregor Mendel’s 189th Birthday, I decided to make a post about pea breeding. On first thought pea breeding doesn’t sound all that interesting. Even to people who are interested in plant breeding in general. I myself thought that Mendel had already worked with all the interesting traits found in peas out there, but i have found that i was wrong. I’m starting to find that the traits Mendel worked with are actually very neat in person, and the ones he didn’t know about are even more interesting.

The Google logo itself is actually a visual representation of Mendel’s experiment of crossing yellow podded peas (recessive) with that of green podded peas (dominant), but it also shows his other experiment of crossing yellow seeds with green seeds. Unfortunately it looks like Google’s logo is not following the law of independent assortment and is showing linkage between yellow pods and yellow seeds, which is incorrect. Yellow seeds are actually dominant, so Google fails in that regard. But, even so it illustrates the ratio of 3:1. In other words, in the F2 generation 3/4 of the offspring will be green-podded and 1/4 yellow podded.

yellow-poded constricted pea pod
yellow-podded pea also with the constricted pod gene (Golden Sweet)

The picture above shows a variety called “Golden Sweet” which remarkably has both the rare yellow-podded gene, but also the gene for constricted pods. After growing this variety for the first time here in my own garden, i can see why Mendel was so fascinated with pea traits at the time. I personally think his experiments were directly inspired by this unique variety of pea, which is suspected to have become close to extinction in Europe and the rest of the world, until it was accidentally rediscovered recently in a collection of seeds from India. It certainly is a pea with some interesting genetics.

breeding peas

I’ve only just started to experiment with crossing peas this year. While it sounds like it would be hard, it’s actually fairly easy. But, it really does help to have a tiny pair of scissors instead of an exacto knife or scalpel. The only hard part is that pea flowers are self fertile and self pollinating by nature, and you must catch the flowers very early to be able to cut off the immature pollen so you can use pollen from another plant. I really don’t know how Mendel did that in his day in age, but i applaud the man. Here are two links to pea breeding on Rebsie Fairholm’s blog.

How to breed your own garden peas
How to hybridise garden peas 

The Results of Mendel's F1 crosses for Seven Characters in Pea Plants
Mendel worked with several different pea traits, and documented at least seven of those. Yellow-podded vs Green-podded, Yellow-seeded vs Green-seeded, Inflated Pods vs Constricted pods, Round seeds vs Wrinkled seeds, Tall vs Dwarf, flower position, and flower color.
Several Pea Traits I’m Currently Researching (I’m actually researching more than seven)
Here is a neat illustrated table of the various pea traits that I’m currently researching. It shows a more accurate color of the purple pea flowers which is known as Bicolour Purple. It also shows Salmon-Flowered, Terminal flowers (fasciated umbellatum-type peas), red-seeded peas, purple-seeded peas, purple podded peas, red-podded peas, Tendril-less peas, and Hyper-Tendril peas. In reality i am studying more than seven traits, but i put the table together as sort of an ode to Mendel.
Purple-podded snow pea 'Midnight Snow'
‘Midnight Snow’ snow pea (purple-podded mangetout / edible-podded pea)
Some of the most interesting pea traits are the ones that i don’t think Mendel even knew existed. Purple-podded seems to be one of the ones Mendel never seems to have written about. But it is widely reported that the purple-podded varieties of peas originated from the Capuchin monks in the Netherlands.
The Unusual Parsley Pea
The Unusual Parsley Pea
Hyper-Tendril peas! (aka. semi-leafless peas)
Hyper-Tendril peas! (aka. semi-leafless peas)

Alan Kapuler of Oregon discovered a while back that if you outcross a pea called “Parsley Pea” which has an insane amount of leaflets on it’s tendrils, that you can get a pea that has hyper-tendrils and has twice the amount of tendrils and doesn’t require a trellis to support themselves.

Rebsie Fairholm's famous red-podded pea
Rebsie Fairholm’s famous red-podded pea

Rebsie Fairholm from the U.K. discovered just a few years ago (2008) that when you cross a purple-podded pea with a yellow-podded pea you get a red-podded pea! How awesome is that!

Pea, Biskopens
Biskopens (rare red-seeded pea). Photo by Soren.


I’m currently trying collect lots of pea varieties with rare and interesting traits, but one that is uniquely rare though is one called Biskopens. It is the only pea that i know of that has red seeds! Yeah, it’s a red-seeded pea!

Pea, Purple Passion
Purple Passion (rare purple-seeded pea). Photo by Soren.

This is a very rare variety i was lucky (and surprised) to get in a recent trade. I really look forward to growing out this variety next spring. Supposedly it also has purple pods. I have no idea what it’s origin is. I’m curious if it’s the same gene as the red Biskopens pea, but perhaps with a green seed underneath so maybe this one comes out purple? I’m just speculating at this point.

Salmon-flowered pea
Salmon-flowered pea

If you are still interested in all of this, then please feel free to visit my pea_breeding webpage to find out more detailed information about pea genetics and about Mendel’s work with peas (as well as  and Rebsie’s red-podded pea). Or my recently updated webpage about the seven-ish unusual pea traits that i’m currently studying at


10 thoughts on “Following in Mendel’s Footsteps

  1. I just googled to find out what the heck the Google logo was about, and you gave me Mendel’s birthday. Thanks!!

    • Well, in all fairness it’s a somewhat pieced together story, so i’m not sure if it’s a reliable story. Seed Savers simply claims it was collected at a market in India as do most seed companies. My main source i was using was from the Long Island Seed project.

      When Will Bonsall through his “Scatterseed Project” began to grow the peas from the USDA Seed Bank (at that time, listed as accession numbers without description), produce crops to evaluate and distribute seeds for the Seed Savers’s Exchange, suddenly gardeners were reintroduced to some very exciting material. That’s how I first obtained seed of Mendel’s Peas. Oddly, the yellow pea came into the USDA Seed Bank via a collection of peas from India. At USDA it sat in some vault for many years. It may very well have been extinct in America and Europe, except for being obtained by USDA researchers and given an accession number. When I saw those golden pods it was a revelation.

    • In addition i have found a few references to some old varieties which were at one time believed to be the same yellow-podded strain as Mendel used. The first, “Gold von Blocksberg”, can be found mentioned on page 158 in Breeding and the Mendelian Discovery. By A. D. Darbishire, 1911. ( The second, “Wachs Schwert”, can be found mentioned on page 379 in the 1927 edition of American Journal of Botany, Volume 14. ( But i can find no mention of their existence even in seed banks past the 1930’s.

  2. Hello,

    I am finally shelling out all my summer legumes, some of which were a group of unlabeled beans that some friends brought from Bosnia when they came to visit. In with the beans were a few dark red/purple peas which I was told were a winter/field pea. I wasn’t able to grow them last fall, so I planted them this spring and they grew wonderfully.

    Tonight I was searching for similar pictures and found your blog. It seems I have some Biskopens peas! I didn’t have many to start with, so not much genetic variety. I’ll grow out a lot of what I have next spring to get the quantity up, and hopefully have enough to try eating some.

    Do you know anything about uses for this pea? Mainly a soup pea, I take it? We grow fodder for our pigs and chickens, and a sturdy heirloom legume would be a great addition, not to mention keeping this variety alive.


    • Hi Joanna,

      I’m glad my blog helped you out!

      I actually havn’t had a chance to actually eat biskopens in any large quantities, but i will tell you what i do know about the Biskopens variety. Yes, it is described as being a “grey pea” which is a european way of saying “soup pea”. The name Biskopens is a shortened version of the original sweedish which was Biskopens Graert which literally means Bishops Grey. There seems to be one seed company that now has started selling some under the english name of Bishops Grey (looks like

      From my observations of growing it so far it does indeed seem to have a very mealy/starchy flavor and thick consitancy, so it’s best use would probably be in some sort of pea soup. There are some people who are actually seeking old “grey” soup peas since they are so uncommon these days, and i truly think the Biskopens variety would fit this need very well.

      You can read a little more on the Homegrown Goodness gardening and plant breeding forum here:

      Also, “Toad”, a friend of mine, and also another member of the Homegrown Goodness gardening forum has provided a nice and authentic old style european recipe for cooking grey peas on his blog. He is from Denmark.

  3. Hi Andrew,
    I’ve enjoyed looking through your blog, and wanted to know if you had an update on your pea breeding? I’m especially intrigued by the ‘Purple Passion’ pea, as I’ve been unable to find it listed anywhere else.

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