Red-podded peas: the 'Roma' mangetout

Creating red-podded peas is quite easy. Pretty much any cross between a yellow-podded and a purple-podded pea should do it. But the somewhat more elusive element is the flavour.

These are my Roma peas, which have been a long time in the making. They are a cross between Golden Sweet, a yellow-podded heritage pea which is still available commercially, and Carruthers' Purple Podded, a rare heirloom from Northern Ireland which I obtained from the Heritage Seed Library many years ago (and no longer have).

The original red-podded result from that cross was stunning and a complete surprise, but it also had some flaws. It was a normal shelling-type pea, like its dad. So I got to enjoy the beauty of the pods in the garden but they had to be grown to full maturity and then the peas shelled out (discarding the beautiful pods) and used like normal peas. Except that they were pretty starchy and bland, which kind of defeated the point. I spent many years trying to select slightly sweeter variants from that original line, but to no avail.

It would make much more sense to breed a mangetout or snap pea with red pods, so that you could actually eat the whole pods and enjoy their beauty on the plate instead of chucking them in the compost. I spent some years making crosses of my original red-podder to various yellow mangetouts from my own breeding projects (which were themselves derived from Golden Sweet). But again the results weren't to my liking. They looked lovely, but the pods always had a soapy bitterness to them. This to me is no good. It would make the variety a novelty, and nothing more. Something you might grow in the garden once as a curiosity and then not bother with again because it didn't taste good enough. We've all grown veg that looks stunning in the garden but is meh on the dinnerplate, and that's not a hall of shame I want to add to.

Then, a breakthrough. In 2019 I grew out some purple-podded mangetout peas that were from exactly the same original cross, with the same genetics, but which had evolved in a different direction. These peas, which I named Barcarolle, were very much purple, and they were also very handsome with a lovely sweet and rich flavour. None of the bitter or soapy flavours that afflicted their red-podded cousins. Well, among this particular batch were a few which were not true to the Barcarolle type. They had red pods. This wasn't entirely surprising as they were from the same original cross and there was always the possibility that they had the recessive gene lurking in their genepool which would express red pods in a small minority of offspring. I tasted a couple of sample pods and was thrilled to find that they had a delicious sweet flavour. So my job then was to save as many seeds from them as possible and then grow out a whole batch of them, hoping the gorgeous flavour would persist.

And here they are. Named Roma, after my dearly loved and much missed mum. Once again I'm growing them primarily for seed, so I've only tasted a few samples. But they were absolutely bloody delicious. I still don't want to get too far ahead of myself and declare that I've found the holy grail I've been seeking all this time, but I am now very very optimistic.

You can read about the development of this project in many previous posts on this blog. But for now I'm just going to bombard you with beautiful pictures. I also made a short video in the garden last night, which I hope will help to illustrate how lovely these are. They have been an absolute joy to me all through their creation (yes, even the frustrating bits) and it feels like the best bit is only just beginning.

Pea breeding projects are go!

What do we have here? 100% germination from 7-year-old pea seeds, that's what!

These are red-podded mangetout peas which represent my best hope of developing a really good, tasty red podded pea. They're a cross between two heritage varieties, Golden Sweet x Carruthers' Purple Podded. These are an F5, so they're five generations removed from the original cross I made. Most of them are the offspring of one particular plant which was exceptional, but I also sowed a few from a couple of other plants which were also very good. I'm expecting most of them to have red pods, but there may be a few yellows, because of the possibility of a recessive gene lurking in their genepool which switches off anthocyanin production. If I'm really lucky they might not be carrying this gene, in which case they should all be red. But I can already see, even when they're just a few days old, that a few of the seedlings look completely green, while the majority have a red blush on the stem. The absence of a red blush may be an indicator that they can't produce anthocyanin, the pigment responsible for red/purple/pink colours in peas. If the anthocyanin switch-off gene is in there, then I would expect it to show up in roughly a quarter of the plants – a simple Mendelian ratio. We will see – it will become more apparent as the seedlings grow, and it's likely that I'll be able to deduce the pod colour without having to wait for them to produce pods.

This project has been languishing for a few years as I've struggled through my bereavements, but fortunately I'm able to pick it up where I left off. I sowed 56 peas in this tray (two in each cell) and they all popped up within 4 to 6 days, with no duds. The seeds were from a crop I harvested in 2019, and no I didn't have special facilities to conserve them – as is my wont, they were stored in grip-seal baggies in a cat food box on top of a bookcase.

I'm all for challenging myths in gardening, of which there are so many. The books on my shelf (just below the cat food boxes) claim that pea seeds have an expected lifespan of 1-2 years. Older than that and they won't germinate, or if they do then they'll make weak plants. I know from experience that this is nonsense. In a previous iteration of this breeding project I germinated 9-year-old pea seeds without any problems at all and the plants were vigorous and healthy. There are limits, of course. I recently experimented with trying to germinate 18-year-old tomato seeds, and it didn't work, despite my best efforts with a heatpad and some home-made gibberellic acid. But whatever the received wisdom says, there's always hope, and it's always worth a try.

I'm thrilled with 100% germination, and very excited to see how they develop.

Meanwhile, here's some I prepared earlier.

I had 98% germination from this batch, which were also 7 years old and from the same cat food box. These are from my pink-flowered pea project, Alderman x Salmon-Flowered, which is aiming to produce beautiful tall delicious shelling peas, but with two-tone pink flowers instead of the standard white. If you've read previous posts on this blog about my pea projects, you'll know that white flowers in peas are caused by the gene which switches off anthocyanin production. Almost all modern peas have it (and many heritage varieties do too) but if it wasn't there, peas would naturally produce PURPLE flowers, and have purple colouring in the leaf axils, peas and pods. As all my projects are concerned with making lovely colours, I aim always to eliminate the "anthocyanin off" gene, which is recessive, so the little bugger pops up in later generations where you didn't know it was there. 

The pink flowers in this project are (I believe) the result of a modifier gene which deletes one of the pigments responsible for purple flowers, giving them a paler, pinker hue.

The photo above shows them when they were in the greenhouse waiting to be planted out. Note that I DON'T advocate leaving them quite this long. If allowed to grow much bigger than this, they'll start grabbing each other with their tendrils and then it becomes really difficult to disentangle them without damaging them. However, the weather forced my hand on this occasion. I was about to plant them out when I saw that a blustery storm was forecast a few days away, and peas really don't like blustery windy weather. So I decided that leaving them in the greenhouse for a bit longer was the lesser evil. As it turned out, I was still able to plant them out before they reached the nightmare tangly tendril stage.

Here they are in their new home, and I'll be writing another post about the swanky new pea frame which I've set up for them.

Red-podded pea update: the F6 crop and beyond

Ever since I first had a red-podded pea turn up (completely unexpectedly) in a breeding project in 2008, I’ve had a bit of a frustrating time trying to get it into a form which is worth releasing into the world. Not that I’ve been trying continually, because I haven’t been able to maintain the garden every year during the last few years, but it has had me scratching my head trying to come up with a way of producing edible pods with this rich crimson colour. Finally, in 2019, I had a significant breakthrough.

The original red-podded pea plant, numbered GSC 15 in my breeding project, was an F2 from a cross between Golden Sweet and Carruthers’ Purple Podded. The purpose of the cross was to breed a new purple mangetout pea for Ben Gabel at Real Seeds, but neither Ben or I had any idea that crossing a yellow pea with a purple one would result in a red colour. It was only this one plant which produced red pods, and it happened because it was a yellow-podded pea with a solid layer of purple pigment on top. The pigment is translucent, so the yellow shining through from under the purple creates a beautiful glowing red, like stained glass.

This breeding line, which is currently somewhere around an F6 or an F7, is now a stable, true-breeding variety. It’s reliable and consistent for all its traits, except one: it still turns up a small minority of offspring whose pods are not fully red. It doesn’t tend to throw any plain yellows any more, at least not in the growouts I’ve done, but it will produce some semi-red plants which look like the red pigment has just been sprayed around the edge, and some which have a jagged, flamed pattern of solid red on a yellow background. I think these are caused when one or other of the two dominant genes for purple pods is unable to express itself. But WHY it can’t express itself I don’t really know. All I know is that it happens often enough to be a thing, and on that basis I don’t think the semi-reds will cease appearing no matter how many years are spent trying to rogue them out. They just have to be accepted as the nature of the beast, and besides, I had one semi-red this year which I liked enough to want to keep it, if I can persuade it to become a variety in its own right.

One of the semi-red phenotypes. I believe it's probably caused by co-dominance between purple and non-purple genes. Because of that, no amount of 'roguing out' will eradicate these oddities, which show up in a small minority of offspring.

But anyway, having reached the F6 generation this stable red-podded variety still has a problem, and the problem is not going to go away. It doesn’t taste good, either as a shelling pea or a mangetout. It has a gristly layer of fibre inside the pod which makes it unsuitable for eating even when it’s small, and if you shell out the peas to eat fresh they are starchy as hell, with a bitter aftertaste. The genes controlling flavour in peas are complicated, but the situation here is very simple – it is true-breeding for crap flavour.

It does, however, look truly stunning.

It’s possible that it will find a use as a soup pea, maybe becoming edible when it’s dried and then boiled for ages. The jury’s still out on that one. But in its current form it’s not suitable for unleashing on the world, and will have to be considered a breeding line. To that end, I grew out a batch of seeds in 2019 which had been in storage for 4 or 5 years, just to replenish my stock of seed. I saved seeds from the best ones (which was most of them, as it’s certainly a fine-looking variety) and saved the rest for taste-testing in the kitchen, some time when I can be arsed to boil up a vat of pease pudding.

So, what to do? I need red-podded peas with edible pods. And ones which taste nice.

When I did my initial report on the edible-pods frustration nearly ten years ago, I said there were five things I could do about it. Here they are again, with the results of my efforts.

1. Stand in the middle of the garden and shout "BOLLOCKS!" in a really loud voice. Yep, done that.

2. Grow out the remaining F2 seeds (about 20 left) in the hope of finding another red-podded phenotype but with edible pods. This didn’t provide what I was looking for, but I did find an extremely nice purple mangetout (the whole point of the breeding project in the first place) which I selected and re-selected in the F3 and named Barcarolle.

3. Grow out the remaining F1 seeds to get more F2 seed. I tried this, as part of a belt and braces approach. Growing out more of the F1 took a year but it yielded plenty of seed. I grew a batch of F2s in 2019 and some of them were quite nice but no, I didn’t get the tasty-edible-red-podder I wanted.

4. Switch to another line of F3 seed, even though none of them are proper red-podders. This was always a good bet, because some of the necessary traits for red mangetout pods are recessive genes which may be hiding in the DNA of a plant which isn’t showing it. For example, yellow is the base colour for red pods and you can’t get red pods without the recessive ‘golden pod’ gene known as gp. The laws of probability suggest that two out of three of the F3 lines should carry the gp gene, even though they don’t themselves have yellow pods. Also, the two genes which produce edible (fibreless) pods are both recessive, so a goodly proportion of inedble-podded lines could produce edible-podded offspring.

Although only one of my original batch had properly red pods, I did get a couple of peachy-coloured or semi-red mangetout lines. My efforts revolved around these, as they were so “nearly there” – they had sweet-flavoured edible pods and a beautiful fiery blush. But sadly the fully red colour didn’t show up in their offspring either.

But although I didn’t get anywhere with the ‘peachy’ F3 lines, it was another F3 line which gave me my breakthrough in 2019, in a completely unexpected place: my Barcarolle purple mangetouts.

5. Grow more of the original red-podded F2 and cross it with something else. I tried a lot of this as well, but it's the most time-consuming option and I don't have many results yet, so I’ll report on it another time.

Barcarolle purple mangetout

Right then, this is what happened with the breakthrough. Alongside my growout of red-podded peas this year, I planted 16 seeds of my newly developed purple mangetout. Sixteen plants is not very many, but I’m doing all my breeding work on a very small scale in my back garden, so that’s all I have room for.

Barcarolle is a very promising variety which originated from the same cross as the red podders – Golden Sweet x Carruthers’ Purple Podded. I selected an F2 plant a few years ago which had beautiful dark velvety purple pods – a really solid dark purple, which is not something you get all that often in peas. As the peas start to swell inside the pod, they bulge through the pod wall and look like a row of little blackcurrants. The reason this happens is because there’s no fibrous membrane inside the pod, like you’d get with a shelling pea. It takes two recessive genes to get the pod walls completely fibreless like this, and it’s a desirable trait to have because it means the pods are fully edible at all stages of development – they don’t go coarse and gristly. I also got lucky with the flavour, as the pods tasted sweet and juicy and were pretty much stringless. Again, this is an uncommon thing to find in a purple-podded pea, because the purple colour is often associated with a slightly bitter flavour. It’s not that the pigment itself is bitter tasting, but there’s some kind of gene linkage going on which means that the purple pod genes are usually inherited alongside some less-desirable flavour genes. This was by far the best purple podded pea I’d ever tasted so I was well chuffed with this plant.

The following year I grew out the F3 generation, and to my delight, it came almost completely true to type. I had expected a few unwanted recessives to show up, but they didn’t. The F3 plants were as uniformly purple and bobbly and sweet and juicy as the previous year’s plant. I don’t always name my breeding projects at this relatively early stage, but it seemed like it was going to be quick and easy to make it into a stabilised variety so I gave it the name Barcarolle. (In case you’re wondering, I play the piano and I’m a big fan of Chopin.)

So then I grew out this batch of F4 plants in 2019, and, well, to say they began to segregate is an understatement. They segregated like buggery. Fortunately they all had the bobbly edible pods (a recessive feature), but they varied in size, flavour, number of pods per node, and most of all they varied for pod colour. In my batch of 16 plants, I ended up with four different pod colours – purple, green, yellow and red!

My 2019 crop of Barcarolle F4 purple mangetouts, segregating for four different pod colours ... aaargh!

I must admit I don’t quite know why this happened. It doesn’t make sense for a variety which is true-to-type in the F3 to suddenly start segregating like mad in the F4. The most likely explanation, I think, is that I happened to grow out (by chance) only seeds which were heterozygous for pod colour in the F3 generation, so they all showed the dominant purple colour but they still had the recessive genes squirrelled away in their genome. Given that I work with such small sample sizes, this is entirely possible. But anyway, who cares – the thing that matters is that I ended up with no less than four red-podded plants, all of them with lovely juicy edible pods. This is such a holy grail for me, some 13 years after I made the original cross, that I spent an awful lot of time just standing in the garden gawping at it.

The purple pods on the left are what Barcarolle is supposed to look like, but it came out with these red podded variants as well.

In some ways I probably shouldn’t be surprised to be getting red pods segregating out from Barcarolle. The only difference between red pods and purple pods is the base colour of the pod – green for purple-podders and yellow for red-podders. Barcarolle is derived from a yellow-podded parent, so the presence of the recessive gp (golden pod) gene shouldn’t be a surprise. I might have saved myself some grief if I’d tried looking for it here earlier.

As well as being exactly what I’ve been looking for for the last decade, the Barcarolle red-podders have some other advantages over my original red-podded pea. The red colour itself is a bit brighter – more scarlet than crimson. Both colours are equally nice when the pods are young, but one slight flaw in the original variety is that the red tends to darken as the pod matures, until they start to look purple rather than red. The reason for this is not a change in the pigment itself, it’s because of the natural darkening of the base colour of the pod. As yellow pods age, they tend to go more green – a trait seen in the parent variety Golden Sweet – and a greener pod means the pigment appears more purple. In the Barcarolle-derived red-podders, the pods stay yellow right through to maturity, and so the pigment continues to look red for a lot longer. I don’t know what subtle genes are responsible for this difference, but it was consistent across all four of the plants in this batch.

The best of them was the plant known as BRC 16 (above), which was hugely productive. It grew to around 7ft tall and not only produced two pods per node, it also developed fully productive sideshoots – a rare thing in peas – and bore good quality pods on those as well. It also did very well in the looks department, having beautiful colour-changing flowers borne on stems with a lot of bright scarlet colour and pretty pink mottling on the calyx. BRC 14 and BRC 06 were both very similar but not quite as vigorous. The best one for flavour was BRC 11 which had a fantastic juicy raw flavour, like apples! 

I do want to develop a red-podded pea which tastes good raw, because the colour is spoiled by cooking. With any red-podded or purple-podded pea, if you cook it any way other than the lightest steaming, the colour just disappears into the cooking water. No amount of careful breeding is going to resolve this, because it’s in the nature of the pigment itself – anthocyanin, which is water-soluble, and that’s just the way it is. So the only thing a plant breeder can do to get around this is to develop varieties which taste so good raw you won’t need to cook them.

Now, of course, I will have to wait until next year before I can grow out the offspring and see how they look. But I’m very optimistic. And I still have the purple-podded Barcarolle line which, once I’ve stabilised it, will be a wonderful variety in its own right. The red-podded line is not named yet, but I have another year or two to think about it.

The Barcarolle-derived red peas have beautiful bicolour flowers which turn blue as they fade, like these on BRC 16.

Please universe, may I have some edible red podded peas?

Golden Sweet x Carruthers' Purple Podded F2. First one to flower.

Today has been a perfect day for hand-pollinating peas. Warm and dry but not too sunny - which creates just the right conditions for pollen to spill its abundance and for stigmatic goo to be in the right mood to receive it. Even more usefully, it was completely breezeless with not so much as a leaf blade stirring. The bitter lessons of trying to hand-pollinate flowers that are thrashing about in the wind, not to mention walking across the garden with a precious blob of pollen on the end of a scalpel, have taught me that pollinations on breezy days are the stuff of futility. All the more so for those of us with waist-length hair, which is guaranteed to flap across your face at the very moment you were trying to deposit a miniscule dab of pollen onto a particularly wobbly and elusive stigma.

As the weather was so perfect for it, I was really hoping to get some useful pollinations done for my red podded pea project. Only trouble is, most of the flowers I want aren't ready. The true red podders aren't even producing buds yet, and my semi-red mangetout line, which I'm hoping to cross with the Luna Trick sugarsnap for some peachy-red snap pods, didn't want to play either. I found a prime pollen-bearing bud on it that was well past the usual stage for self-fertilisation but when I cut it open I found it stubbornly refusing to dehisce.


An F4 plant from my semi-red podded mangetout line, currently struggling under the temporary working name of Peachy, getting ready for some blossom action (but not yet).

So instead I did some pollinations I didn't really need using the flowers I had available. It is worth pointing out that my beloved Luna Trick pea is the result of just such a casual union, in which I used up the last of some Sugar Ann flowers to pollinate a few buds of Golden Sweet just because I was bored. It turned out to be an inspired combination. Today's efforts mostly involved Sugar Snap flowers as females, pollinated with some of my purple F2 plants which may or may not turn out to be any good. I used the opportunity to take some close-up photographs of the pollination process. It's my fourth attempt to take such pictures. Thing is, you really need three hands for it, or an assistant who knows what they're doing. I have neither, so Plan B was to stick the camera on a tripod and use the self-timer for some very cumbersome hands-free photography, which resolved the three-hands issue but gave me some more challenges in trying to get it to focus in the right place when there's negligible depth of field. Anyway, if any of them are any good I'll add them to my previous pea-breeding tutorial.

The hand pollinations are just one aspect of what I'm doing on this crimson seeking project. Since my pièce de résistance in the red podded pea department stubbornly refused to yield me any fibre-free pods, I've been looking at alternative ways of getting them. Which now involves several simultaneous endeavours.

Growing out the rest of the F2 seed from whence the original came. This is the biggest hope. The particular combination of genes I need are a minority class which will only show up in a small proportion of the F2 offspring. I need the yellow pod gene (recessive), two purple pod genes (both dominant) and two fibre-thwarting genes (both recessive). I can't be arsed to look up in a Punnett Square what the actual chances are and calculate the number of plants I need for 95% probability … I'm content to know that it may take a lot of plants in order to deliver the holy grail. This year it's down to luck anyway, as I have only a small amount of F2 seed left and so I can't grow lots of plants. Even the seed I do have is of poor quality because it was grown from a late summer crop (I used to have this trick of growing two consecutive generations in one season to double the speed of my breeding work, but have since stopped doing it because the second crop yields weak seed at best, and at worst yields nothing and just wastes valuable breeding material). So I have about fifteen, maybe twenty plants, and they may or may not offer any red pods. The moment of truth is approaching, as the F2 plants have got flower buds.





They're very pretty buds, with the mauve blush that promises bicolour flowers. Both parent varieties had bicolour flowers, so I'm expecting to see it in all the offspring. The ones shown above are fairly typical and there are others similar, with more or less purple sploshing on the stems and leaves. But I can already categorically rule out any red pods from these two plants or any of the others currently budding. The reason? Green calyx.

Green calyx means green pods. I've noticed from my work with yellow podded peas that there is a direct correlation between the calyx colour and the pod colour. Yellow podded peas are always preceded by pale cream buds which turn into a cream calyx. Sometimes it has green mottling, and pink dapples, but the base colour is always cream. (Have a look at the picture of Peachy above and see how cream the calyx is compared to these F2 buds). I suspect the cream calyx/yellow pod may actually be coded by the same gene. If they are separate genes, they are certainly slapped together pretty tightly on the chromosome, and inherit together. It's not affected by flower colour - you can get white flowers or purple bicolour flowers on a yellow-podded pea, it's just the calyx and pod colour that are inseparable from each other.

When I say that green calyx means green pods, it may also mean purple pods … or partial purple. That's because purple podded peas are in fact green podded. I know that sounds weird, and I've had to explain it so many times on plant breeding forums it's obviously something a lot of people find hard to follow. If you look closely at a purple pod, the very tip where it attaches onto the plant is green. Break it open and it will be green inside. The purple pigment, no matter how intense it looks, is merely on the surface, and the base colour of the pod is green. This is also the reason why all purple podded peas turn green when cooked. The water-soluble anthocyanin pigment is just sitting on the surface and is washed away in hot water.

I admit it did take me a while to work this out. The first time I grew F2 seeds from this cross, it produced red, green, yellow and purple pods in varying proportions. I couldn't understand why a cross between a purple podder and a yellow podder yielded so many offspring with green pods. Neither of the parents appeared to have green pods so where did they come from? The simple answer is that the purple parent is green podded, with the green hidden under the layer of purple. In the great gene reshuffle, some of the offspring end up with green pods without the genes for purple overlay, and so they stay green.

The same principle applies to red pods. They are simply yellow-podded peas with a purple overlay, which combines visually to make deep red. It's not possible to have red pods unless the base colour of the pod is yellow. That's how I know the two buds shown above are not going to give me red pods. A red-podder bud will invariably have a cream calyx, not a green one.

While I shouldn't condone the practice of peeking inside unopened leaf clusters to look at bud colours, I naturally can't resist it. And it's been very encouraging. Because two of the upcoming F2 plants which are not ready to blossom yet are showing cream buds among distinctly yellowy foliage. Even when they're tiny, the cream colour is unmistakable. The cream buds don't necessarily result in red pods, some will just stay yellow, it depends whether the genes for purple overlay are also present. But they do open up the likelihood of it. Also, one of the cream buds is showing a speck of pink colour on the calyx. While I don't have a genetic explanation for it, I have noticed a strong correlation between pink markings on the calyx and red pods. So I'm feeling lucky with this one.


Maybe it's not very clear in this photo, but this developing bud has a cream calyx - ergo yellow pods. Also a tiny pink spot on the calyx which is a good sign.

It's still pot luck whether any of the plants in this small sample will give me exactly what I want, but the solution is in there if only I can grow enough F2 plants. Which brings me on to my convenient back-up plan …


Growing out more F1 plants to make new F2 seed. I still have a number of F1 seeds saved from when I made the original cross. The seeds are good, healthy mature ones too. I started off a batch of about ten F1 plants this year. The beauty of peas and their efficient self-pollination is that you don't need to do anything except grow the F1 plants and save seed from them. They are veritable F2 seed machines. Every pea they produce has a unique individual genome, its own personal reshuffling of all those genetic goodies. Somewhere among the reshuffles is bound to be the specific five-gene combination I'm looking for.


F1 hybrid of Golden Sweet x Carruthers' Purple Podded. Flowering like billy-o and hopefully making lots of nice F2 seeds for me.

What's interesting about these F1 plants is that they are showing massive hybrid vigour, or heterosis. It's a phenomenon brought about by having a mixed up genome, a by-product of heterozygosity. Its cause has always been something of a mystery, though I'm told that some recent research has put it down to an enhanced ability for photosynthesis. Whatever the reason for it, my own observation is that it only happens in certain crosses - though there are degrees of it. And it's for one generation only - you don't tend to see it in F2 plants. This has been especially marked in my current crop, because I sowed the F1 and F2 seeds from the same cross side by side in the same rootrainer tray, and they are now growing side by side out in the garden. And from the moment of germination, the F1 plants rocketed away from their F2 nephews. They grew faster, had thicker stems, established themselves in the outdoors quicker, produced substantially bigger leaves and grew taller. They were also earlier to flower - and still having a burst of surplus energy to get shot of, have thrown out a lot of sideshoots too. Pea sideshoots are usually feeble, spindly things, if they ever get going at all. These are nothing of the sort. They are full-size, chunky, vigorous new branches which look set to flower and make pods.

Something else peculiar about the F1 plants, or one of them at least. I've been writing about the leaf aberrations in my peas this year, which I'm beginning to conclude are probably weather related. I mentioned the fasciation (thickening of the stem) in one of my other hybrids, despite the fact that it's a trait caused by recessive genes. Well, now some spontaneous fasciation has occurred in one of these F1 plants. To my knowledge, there are no fasciation genes in this hybrid, which is not related to the other one - they are completely separate breeding lines. Which leads me to assume that pea fasciation is not solely genetic, and can arise as an environmental reaction. What's even more weird is that the plant in question managed to unfasciate itself by splitting into two stems. A single stem with a well developed sideshoot is one thing, but this is a pair of twin stems growing at the same rate in different directions, equal and opposite.


This F1 pea developed spontaneous fasciation (stem widening) and then split into two separate but equal growing tips. This is not normal for peas!

Edit: I've just done some homework on fasciation, following a link from Rhizowen's wonderful blog, and it seems that spontaneous fasciation from environmental stress is a well known phenomenon - actually more common than genetic fasciation. It's caused by damage to the growing tip by virus, bacteria, insect nibbling or frost - and a reversion back to normal growth is also common. In this case, frost is almost certainly the culprit.

Other avenues. I had just eight seeds left from my original red podded pea. I sowed them, and three fell victim to marauding gastropods. The five survivors are doing well though, and although there will be no edible pods among them, they will enable me to make some crosses. The priority will be to cross them with my two Luna Trick lines, which are genetically similar, being derived from the same original parent variety, but represent a superior form of it with good-flavoured and fully edible yellow pods. Another batch of twenty or so are on the go, thanks to my big haired friend Graham, who grew some last year and gave me back some seeds from the best of them. Again, they won't have edible pods, but they will be priceless for making crosses and might also make the basis for a red-podded shelling pea. Also of course there's the Peachy line which has edible pods which are part-red. That might turn into a variety in its own right, and will certainly be useful for making crosses with the pure red (if it ever gives me any pollen).

Red-podded pea update: the F3 crop

The unexpected discovery of the 'formula' for red-podded peas was the most exciting thing to happen in the garden in 2008. Without even meaning to, I'd created something unique and special and was very excited about what it might evolve into. Following all this excitement and expectation, its progress in 2009 was frustrating to say the least.

To recap briefly: I was working with two crosses, both involving a purple shelling pea with a golden yellow mangetout, with the aim of breeding a new purple mangetout variety for The Real Seed Catalogue. One of these crosses was Golden Sweet x Carruthers' Purple Podded, and among the F2 plants (the generation where all the genetic recombination happens) I found one single plant with deepest, richest blood red pods.



Beauty is not enough though, as spectacular as it is. Commercial seed catalogues are already rife with things which look good but don't taste particularly special. So much so, you could be forgiven for assuming there is a tradeoff between beauty and flavour (which there isn't) and that pretty vegetables will inevitably taste rubbish. I don't want that to happen with my red-podder. I want it to taste as good as it looks, otherwise there really is little point in it.

The original red-podded F2 plant was, unfortunately, a normal shelling pea with a fibrous membrane inside the pod. What I need is an edible podded version - which means a pod which doesn't produce a gristly inner membrane. The absence of fibre is actually achieved by the combination of two unrelated genes, both recessive. Golden Sweet, the 'mother' of red-podder, is a mangetout and has at least one of these genes, if not both. So even though red-podder itself had fibrous pods, there was a pretty good chance that it would be heterozygous at that locus - carrying a hidden recessive gene for edible pods. In fact, by the rule of Mendelian segregation it had a two in three chance of producing some edible pods, and only a one in three chance of being all gristly and inedible. Until I grew the next generation, I had no way of knowing whether it was heterozygous for that trait (carrying some variability) or homozygous (true breeding).



So in 2009 I grew the F3 plants. As the red-podded phenotype was only really asserted in one plant in my F2 crop, my F3 crop was based solely on the offspring from that one plant. The plants were absolutely stunningly gorgeous. Most of them had deep red pods, though some were coming out as plain yellows, and they all had wonderful rich colouring on the stems and tendrils, and attractive calyx markings. When the sun shines through the red pods they are out of this world.

Alas, growing the F3 revealed that red-podder is homozygous for gristly pods. In other words, it cannot produce edible pods. Homozygosity is a blessing for stabilising the traits you want. But when a trait you don't want is homozygous, you're stuffed. I could grow the offspring of my red pea for the next 100 years and probably never see an edible pod among them. The genes for edible pods are not there. It has only the genes which breed true for solid, yukky, gristly fibre.

There are five things I can do about this:

1. Stand in the middle of the garden and shout "BOLLOCKS!" in a really loud voice.

2. Go back to the F2 generation and grow out the rest of the seeds (I have about 20 left) in the hope of finding another red-podded phenotype but with edible pods.

3. Go back to an earlier generation still, the F1 seeds, and grow out some more of those. These plants will all look the same, all boring, with no red pods. But they will produce a fresh abundance of F2 seed, which I will be able to sow next year and that will give me a much better chance of an edible red-podded phenotype in the event that option 2 above doesn't yield anything.

4. I can switch to another line of F3 seed, even though none of them are proper red-podders. For example, I do have an F3 which is edible podded and produces yellow pods with a red blush. It's possible that if I grow out enough of its offspring I might get something with a stronger red. It should at least breed true for edible pods, which is half the battle. Even if it doesn't produce a decent red, it might make a nice variety in its own right - kind of peachy auburn!

5. I can grow my remaining seed from the red-podded F2 and cross it with something else. To retain the red pods I would need to cross it only with yellow podded peas - and mangetout ones at that. The most obvious thing would be a backcross to Golden Sweet, but I can go one better than that. My Luna Trick line, although not yet stabilised, is bred from Golden Sweet but is a huge improvement on it. A cross with that would give me an excellent chance of improving red podder's flavour as well as its pod structure. The other obvious cross to make is with option 4 above, which already has most of the right genes.



Apart from option 1, they will all take some time - at least a year and probably more - to get the results I want. But no matter, I have got all of them underway now. We'll see what 2010 brings.

Red-podded pea update

All together now ... oooooooooooh!!

The red-podded peas have now completed their life cycle, and in fact have started a new one, because I've already sown a batch of their F3 offspring.

Red-podded peas were an unexpected gift from my Purple Mangetout Project, which I'm doing on behalf of The Real Seed Catalogue. I really have to thank Ben of Real Seeds for making it happen. He sent me the Golden Sweet seeds to experiment with and I don't think I would have thought of crossing Golden Sweet with a purple podded pea if he hadn't suggested it. It was a good choice ... I think there's a distinct lack of genetic diversity in peas generally, and as I'm discovering in this and other projects, Golden Sweet is something really different and brings a heck of a lot of useful genetic material into the mix.

Among my F2 plants there is just one, known as GSC15, which has pure deep red pods. GSC stands for "Golden Sweet x Carruthers", followed by a number. It's just my own little code for identifying individual plants.

Here's what GSC15 looked like at various stages.

Ooooooh ....

Aaaaaah ...

Yeah ...

This plant always looked special and highly coloured, and in fact I posted a couple of photographs of it when it was just a seedling, because it was the most beautiful of the seedlings. It's turned into an amazingly beautiful mature plant. It has a whole range of candy colours as well as the spectacular crimson pods, even producing two-tone pink and yellow tendrils. It's an improvement on Golden Sweet, the parent it inherited its colours from. It grew vigorously and elegantly, and also had the grace to produce two pods per node. It really is a winner. There has to be something imperfect about it though, and I think that might be in the pods themselves. It's clearly not a true mangetout because it has some fibre and leatheriness in the pods. But I'm not sure it's cut out to be a sheller either ... the one pea I ate was a little bit starchy. It would be a shame if you couldn't eat the red pods anyway, so I'm looking to develop a fibre-free version.

This is not really a problem. The next generation is likely to show more segregation for hidden recessive traits and there's a good chance, I think, that I'll get something with the same strong colour but a true mangetout, or sweeter peas.

GSC15: the young leaves have a yellow tint to them, and a deep pink blotch in every leaf axil. The flowers are bicolour maroon and mauve, a trait inherited from both parents.

Even the tendrils are beautiful. The stems are peachy pink and the tendrils bright yellow. It's a difficult thing to photograph and this really doesn't do justice to it but you can see the contrast here as it clings to the ordinary green tendril of one of its siblings.

Yellow-podded peas always show a lot of yellow in the young leaves as the plant reaches the flowering stage, and of course red-podded peas ARE yellow-podded, with an extra layer of purple over the top to create the red. So GSC15 shows all the colours you'd expect in a yellow pea, with some additional pinky colours. The calyx (pixie hat) on the flower buds are pale cream but show quite a lot of pink streaking, which is something I haven't seen in any other plants ... but it is a natural enough combination of parental traits ... Golden Sweet is the source of the cream calyx while Carruthers' Purple Podded provides the pink streaks.

GSC15 plant top ... yellow leaves with a very bold, bright pink splodge in the leaf axil and also some strong pink markings on the flower buds.

Although GSC15 is the clear champion of this batch of plants, there were other red-podded peas which were mostly red but maintained some of the underlying yellow. Some more than others. GSC09 is quite promising ... it's a true mangetout, and the one pod I tasted was very nice. The red colour is quite patchy in places though, with only a few showing a dominance of red. The photo at the top of this post shows a GSC09 pod, one of the less yellowy patchy ones. Again, I'm hoping some further segregation in the F3 generation will give me more mangetouts like this but with a stronger colour.

Initially the red podders were all from my Golden Sweet x Carruthers cross, but later a couple showed up in the Golden Sweet x Desiree cross as well. The GSD plants were both dwarf phenotypes with mostly yellow pods and only a spraying of red. They don't look as promising as the GSC ones but it's interesting that this happened at all ... it suggests that any cross between a purple and a yellow podded pea could potentially produce red pods, and it's not an exclusive feature of the Golden Sweet x Carruthers cross.

Flowers on a red-podded Golden Sweet x Desiree hybrid. Again it's a beautiful highly coloured plant with two flowers per node, although it only grows to a foot or two in height.

Depending on what traits show up in future generations, I may develop the semi-red peas into a new variety in their own right. They have a charm of their own, and although they're not as spectacular as the true reds, they are still a unique colour break. Some of them are yellow with just a bit of red edging, others are lightly "sprayed" with red all over, giving a peachy effect.

Bicolour yellow and red pods, one of the Golden Sweet x Desiree plants.

The next stage is to grow the seeds from all the red-podders. Normally in a breeding project you have to cross the F2 plants with each other to produce the F3. As peas are self-pollinating, however, all you have to do is leave them to produce seed naturally. There's still time for me to get another generation grown in 2008 as long as I start them off pretty promptly, so I've been harvesting the pods as soon as they reach maturity and drying them in trays indoors. I judge "maturity" as the time when the calyx starts to dry out and the top of the pod (where it joins on to the plant) starts to look a bit sunken and leathery. I save the seeds from each plant separately, which is a lot of work but enables me to keep track of everything in future generations, and learn from it.

In addition to starting off a batch of F3s, I've sown another lot of F2s as I still had plenty of F2 seeds left. I'm hoping there will be some more red-podders among them which will give me more material to work with and hopefully more genetic combinations.

The first few GSC15 pods drying indoors. The pods go purple as they dry out, and the peas stay green but shrivel to a tiny size. YSS10 is one of the beautiful bicolour-flowered types from my yellow sugarsnap project. I alternate them so they don't get muddled up.

What do you get when you cross a purple-podded pea with a yellow-podded pea?

Well the answer is mostly GREEN podded peas, actually. That's something I hadn't predicted and I don't quite know why it's happening.

You also of course get some yellow podders and purple podders as the genes segregate out. The photo above shows some Golden Sweet x Desiree F2 plants ... these are siblings from the same batch of seeds and have segregated into yellows and purples (as well as greens).

And then this suddenly shows up:


This is one of my Golden Sweet x Carruthers' Purple Podded F2 plants. I noticed it had slightly different colouring from the others when the flower buds appeared. The sepals were cream-coloured which is a sure sign that yellow pods will follow, but they were also liberally flushed with pinky red.

When the first flower died off and the pod emerged, it was indeed yellow. But when it was a day or two old it started to develop a peachy blush down one edge. The colour seemed to be darkening by the hour and I wondered how far it would go. Would it stay peachy and localised, or fill in the whole pod?

The next day it had turned fiery orange.


I mentioned in my Yellow Sugarsnap post (below) that one of the joys of home plant breeding is the unexpected new phenotypes, unique traits created by the great gene lottery. But this is not just a new phenotype, it appears to be a completely new colour break. I don't know of any other peas this colour anywhere in the world. How exciting is that?!

It may be a colour I've never seen before, but it's easy enough to explain how it came about. Purple podded peas start off green, with the purple developing gradually after a few days. Sometimes the purple fills the whole pod, sometimes it retains a bit of the green. But essentially you don't get true purple pods, they're always green pods with a purple overlay. The purple colour is made by a common and naturally occurring plant pigment, anthocyanin. It can create pinks, reds, violets, purples, blues and blacks, in various parts of the plant.

All that's happened here is that the gene for yellow pods has met up and made a harmonious partnership with the gene for anthocyanin-in-the-pods. In other words, it's a normal purple podded pea but instead of having the usual green base, it has a yellow base. And the yellow shines through from underneath and makes it go red instead of purple.

And when I say RED ...


I bloody mean it. No Photoshopping here. These pods are deep, rich, blood red!

I hope this illustrates how incredibly worthwhile garden plant breeding really is. I was put off plant breeding for years because I'd always read that you need to grow thousands of plants to be in with a chance of getting anything useful out of it, and that it takes years and years and years of work. But that's bollocks, as you can see. Carol Deppe changed all that with her radical claim that you can do plant breeding on any scale and it really isn't difficult. She's absolutely right. This amazing pod colour has emerged spontaneously from a project which I started barely 12 months ago. All I did was a single round of hand-pollinations, and saved and grew the seed for two generations (all in the space of a year). And I didn't have to grow thousands of plants ... in fact I only have sixteen.

I've made two previous posts with instructions for hand-pollinating peas, if anyone wants to give it a go ... here and here.

If this doesn't get you reaching for your pollinating scalpel I dunno what will ... !

(Oh, and this pic was taken with the new Nikon.)