Wednesday, 18 March 2009

Pea: Luna Trick

Last year's F2 plant which became the prototype for Luna Trick

I have at least three or four plant breeding projects which will be ready for naming in 2009.

This is the first ... a new mangetout (snow) pea called Luna Trick.

Named in honour of my friend and music collaborator Daniel Staniforth, a shining inspiration who plays cello for me along with a seemingly endless range of other instruments; Daniel releases his own alt-rock music under the name of Luna Trick, so this beautiful moon-like pea is for him.

Prototype, photographed 2008

Luna Trick was bred from a cross of Golden Sweet x Sugar Ann. It was one of the obvious stand-out phenotypes in the F2 generation in 2008, producing a beautiful and abundant plant, though its greatest asset is its outstanding flavour (which must be carefully selected for in future generations). This is what the variety should look like when it's stabilised:

Growing vigorously to 6ft, it has distinctive yellow-green stems, and bears single rounded moon-white flowers on pale yellow stems so curvy they sometimes turn right over and bloom upside-down. The calyx is cream when young but at maturity turns moon-white with green mottling. Pods are pale yellow, quite large and succulent. As they mature they take on a porcelain-like translucence and the small peas can be seen inside, 8 or 9 per pod. Being a mangetout type, Luna Trick is completely fibreless and the pods are edible at all stages. The absence of fibre helps give it its translucence but it also means that the pod cannot keep its flat shape at maturity ... the peas bulge through and the pod buckles and twists, taking on a crescent shape. The really special feature is the pod flavour, which is exquisitely sweet, and a major improvement on its yellow-podded parent. The flavour has a full and rounded character as well as being sweet, and the thickish pod walls are unusually juicy. Even at a large size they can be eaten straight off the plant with no trace of bitterness. The peas themselves are not huge but very abundant, and sweet enough to be worth eating in their own right, raising the possibility of this being a dual-purpose variety. The one fault the peas have is a tendency for the skins to split if watered too heavily or erratically (either by me or the English weather).

The absence of any fibre inside the pod makes it impossible for it to stay flat. It's a bit weird-looking, but I rather like it. The pods also turn porcelain-translucent as they mature, so you can see the peas inside.

Although this pea has got its name this year, that doesn't mean it's ready for general release ... it will probably need at least another year's work. The basic format of a breeding project goes like this: two varieties are crossed together to make an F1 hybrid. The F1 seeds are all mixed together and don't get a name or a number ... there's no point, as they all look pretty much the same. The only purpose of the F1 generation is to provide as much F2 seed as possible. The F2 generation is where the magic happens ... as all the genes in the lottery get re-shuffled randomly and create enormous differences between siblings. So I treat each F2 seed as a unique individual and give it its own identifying number. Once I've decided which of the resulting F2 phenotypes are worth pursuing, the number is then applied to all subsequent generations so I can keep track of its lineage. In this instance, the plant I wanted to keep was one called YSS 25 - quite simply plant number 25 in my Yellow Sugar Snap project (which so far has produced just about every imaginable phenotype except a yellow sugar snap, but never mind). So at the end of last season I collected all the seeds from YSS 25, and these are now F3 seeds. Although they will display a certain amount of variability they should mostly follow the blueprint set in the previous generation, so they don't get their own individual numbers ... they are collectively labelled YSS 25 F3, and are now the basis for a new variety. It needs to keep its number so I don't lose track of its pedigree, but you can see why I prefer to call it Luna Trick.

2009: new seedlings just starting to sprout. This is the F3 generation

It's still early days on this project, but I'm hopeful that Luna Trick will be among the first of the new pea varieties to be released. Why? Because most of its desirable traits are made by recessive genes. Recessives are the joy of a plant breeder's life because they are so easy to stabilise. For example, the yellow pods are made by a recessive gene called gp (golden pod). I can deduce that the Luna Trick prototype carried a perfect matched pair of gp genes ... because if it didn't it wouldn't be able to express yellow pods. If it had only one copy of gp it would default to green pods, with the yellows just showing up in a proportion of its offspring. The fact that it was yellow-podded means I can be fairly confident that all its offspring will be yellow-podded, because it has only gp genes to pass on. The same is true of many of its other traits ... it has matched pairs of recessive genes for fibreless pods (two genes), white flowers (one gene) and for sweet flavour (two or more genes), so I can expect it to have high levels of stability for all these traits. These characteristics are joyfully easy to predict.

Some of the variability is also predictable. Tallness is a dominant trait in peas, made by a gene called Le. The original Luna Trick plant was tall, but it was bred from a cross between a tall pea and a dwarf one so I don't yet know whether it has one copy of the Le gene or two. If it has inherited two, it will breed true for tallness. If it has only inherited one (which is statistically more likely) then I can expect to see the recessive dwarf gene show up in a quarter of the offspring, and I will have to keep selecting the tall ones for several generations until the dwarves stop showing up.

Fortunately with peas you can recognise tall and dwarf phenotypes very early on, while they're still young seedlings. This is because the difference between a tall pea and a short one is simply down to internode length ... the amount of stem it makes between each set of leaves ... which starts to show itself when the plants are only a few days old. Thus I should be able to "rogue out" any shorties before I even plant them in the garden. Though I will probably plant them separately from the others and keep some seed from them, just in case I ever want to create a short version of the variety. (My breeding work focuses on tall peas as they are wonderful and deserve a renaissance after being woefully neglected for the last 100 years, but some people do like dwarf peas so I'll keep the options open.)

You can also see from this picture that it has variability in the seed colour, and comes in cream or green. The colour of a pea seed is made by the cotyledons (seed leaves) hidden inside. The dominant cotyledon colour in peas is yellow/cream ... and clearly Luna Trick has inherited this ... but it has also inherited a recessive gene catchily called i, which produces green cotyledons. (Put into technical terms, it's heterozygous at the i locus.) I could select one colour or the other ... the green ones, being recessive, will breed true for greenness, while the dominant cream ones may be hiding recessives within them and will show some further variability. But I'm actually not fussed either way ... the seed colour is not especially relevant in this project, so I'm planting them all without selection. If I was a commercial plant breeder I would probably want to select more rigorously to get a uniform product ... but I'm not, so I'm more interested in maintaining a healthy bit of genetic diversity.

Having made all these predictions, "expect the unexpected" is the mantra of any gene-reshuffling endeavour. It's likely that I'll find some unforeseen variability in the twenty-five or so plants I'm growing in this generation. Some will be caused by hidden recessives making their presence felt, and some will be caused by pleiotropy (genes which have more than one function) and unexpected synergies between newly combined genes. But that's OK ... for me it's one of life's greatest joys to see these new plants emerge into the world, each one subtly unique, and see what gifts they have to offer.

More information about pea genetics can be found in the JIC Pisum Gene Database.


Maggie said...

As always, a great read. Thanks for including the link at the end. I was going to ask for a reference to a pea breeders bible that might provide more illumination on known recessive/dominant traits. I credit your blog with substantially increasing my interest in plant breeding. Thanks for that!

Anonymous said...

Very cool pea. Congratulations!

Anonymous said...

that is a beautiful looking plant.

Owen Bridge said...

Wow, that's an amazing sounding pea! After reading about your projects I'm really keen on experimenting with pea breeding myself this year, so thanks for the inspiration!

Celia Hart said...

Good to have an update on you pea breeding experiments.

Here's to a good growing season!


Kath said...

What a lovely looking pea. I've only got an F1 generation to grow out this year but you are keeping me going!

Garden Girl said...

Glad to get your update. Always fascinating to read about your projects. Looking forward to a wonderful growing season, and to updates about your red (!) peas too.

Happy Spring!

timx said...

Absolutely fascinating, as ever - to be both technical and readable is an achievement on its own, and to produce a new plant as well...

Anonymous said...

Nice work! Glad to hear someone else championing tall legumes. They're really so well adapted for home gardeners, especially in cool and wet climates, like mine and yours. The yields for a given amount of garden space is so much greater than for short types, and they dry a lot better being further away from the ground. Well worth the effort of providing support, I think...

chaiselongue said...

This is fascinating! Thanks for explaining it all. It seems a miracle always when a plant grows from a seed, but when it's a variety you've created yourself it must be a hundred times more exciting.

Anonymous said...

Good to have you back Rebsie!

That looks like a really beautiful pea. I know I owe you some bean seed but I've lost your address (computer woes)!

Anonymous said...

Was beginning to worry about you. Glad to see you back!

Anonymous said...

Looks wonderful Rebsie. We cannot import pea seeds into Australia, or any legume seeds for that matter, so I'll just have to try my hand at creating something similar.
How does one go about distinguishing snows from snaps from shellies? Is it a case of eating them at various stages to see if a fibre layer develops?

Rebsie Fairholm said...

Thank you very much everyone. Much appreciated.

Ray, you can usually recognise different pod types without eating them. You can see from the picture here what happens to fibreless pods ... they don't always buckle as extremely as this, but at the very least they will tend to shrink around the peas so the peas stand out very prominently. A pod that keeps its smooth shape at maturity is most likely fibrous.

The difference between snows and snaps is less obvious, because it's the thickness of the pod wall that makes a snap ... but snaps tend to produce more slender pods (I guess there's a trade off between width and thickness) and you can often spot them because they just "look" like snaps.

Alternatively, you can harvest and dry the pods and then look for the fibre layer when you're shelling out the seeds. Fibre-free pods go leathery and shrink around the seeds. Fibrous ones have a smooth shiny layer inside, and sometimes spring open as you shell them.

Anonymous said...

You have an award! It's on my blog

Ottawa Gardener said...

Well, I'm definitely going to be keeping an eye on this pea because of its obvious beauty and your appraisal of its taste and because it bares the name of my daughter! She'd get a kick out of a pea named Luna.

Degringolade said...

Thank you for the blog. I was just starting out on my pea patch this year and was writing about my thoughts on cross-breeding some tomatoes. I ran across your blog and I am more than pleased when I found out that I like both your gardening primers and your music.

You are definitely going onto my "gotta read these folks" list. Thank you again for the blog


Robbiegirl said...

Golden Sweet X Sugar Ann is on my to-do list of crosses for this year, thought I'd try for a yellow sugarsnap.

Also planning Golden Sweet X Purple Podded, hopefully to get my own red pea!

Steelanger said...

You have to go at least until f6, but it is highly reccomendend to go up to f7 in order to obtain a homogene line.

Of course after every generation you have to select the plants that display de characters you want.

Commonweeder said...

Fascinating. I can't imagine the thought and patience that goes into hybridizing. Your interests and skills are certainly broad. Beautiful blog.

Stan Gibbs said...

Just wanted to know if you would be open to selling advertising on your blog to related gardening sites. If yes, please get in touch with me as I would be interested in buying an ad. I could not find an email address on your blog which is why I am commenting here. Please feel free to delete this comment. Thank you!

Unknown said...

Nice blog..very nice indeed. I planted two raised beds this year. I cannot wait for the production to begin.

I am very impressed with your pea breeding.

Robert Brenchley said...

Please keep the blog going! It's too good to let it die out, and I want to know what happens to the umbellifer peas you were trying out.

Sendacow said...

Lovely pics, well done! Love the blog :-) You may be interested in the work of Send a Cow - - We are based in Bath, but work with rural community groups in nine countries in Africa, providing small-scale farmers with the skills and means to feed their families and earn an income. It's all about helping to develop sustainable farming methods!

Madeline McKeever said...

It is very quiet in 'pealand'. I would like to here how you got on this year. I would especially like news of the red peas.

Sue Garrett said...

Sorry that this is probably not the best place for this but I couldn't find a contact address.
Also apologies if I have posted about this before but I can be a bit overenthusiastic in my attempts to raise awareness of this topic.

I'm sure you must be aware of the problems experienced by allotment holders last year due to the use of manure contaminated by a persistent herbicide called aminopyralid. Information has been collated about this problem from the links on this page
Just to update on the latest re aminopyralid contamination in case you would like to provide updates on your website or to allotment holders in your area.

The latest information re manure contamination is posted on my website here
I have also sent out a email for circulation by everyone I know that has been affected which is here which you may find useful to circulate to allotment holders in your area.

It is particularly important that gardeners be aware of the need for caution when obtaining manure in light of the fact that the government are now considering reinstating the licence that was temporarily suspended last year. As this is a concern to many gardeners you may wish to publicise an a epetition that has been started here

I am posting updates as I get them on my blog just on case you want to keep a watching brief.

barkingdog said...

Are you okay Rebsie? You are very quiet?

thpt said...

I've been an avid follower of your blog. It's a beautiful and educational thing of wonder.

I hope that your absence is due to business with other wonderful projects. In which case, YEAY YOU!

If not, fake it anyway. We'll never know, and will just be glad you're back. :)

Anonymous said...

Good Day Cevenol

wish to be read

I am Elizah Leigh , co-owner of the website and a green enthusiast.
We are trying to spread organic farming / gardening in order to create a more self-sufficient world by writing guides about these issues.
Our point is not to be as academic as possible, our belief is that too much information only scares the aspiring gardeners so we try to remain understandable while being accurate.
As of now, our website is really new but we're trying to upload content as much as we can, this is usually an article of about 400 words every 24 hours because of our situation as students.
I only as that you visit and take a look, tell us how to improve ourselves and perhaps if you're willing; give a LINK to us or REVIEW our website, so we can get some recognition. Granted, we'll probably never be able to become as popular as some other websites on this subject, but I think we deserve a bit more traffic with the work we're putting into this.
I am looking forward to hearing your advice and impression for our humble beginning. I'm sure you won't miss the opportunity to help youngsters out.

sarah said...

Rebsie, I guess you are done blogging. It happens. Hope you are happy and all the breeding projects worked out. Thanks for all the inspiration and all the best.
Thanks again,

Anonymous said...

pity! would dearly love to know how the pea breeding progressed in 2009

Dirty Girl Gardening said...

what a gorgeous little pea.. lovely color.

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This comment has been removed by a blog administrator.
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AMIT said...
This comment has been removed by a blog administrator.
JackieB said...

It's been a year. I still come back occasionally to see if there are updates. I miss your blog a lot. Your enthusiasm and knowledge were greatly appreciated.

Hope you are doing well and just too busy to write. Best wishes with your future endeavors.

Storymaker said...

I've noticed you sometimes complain about problems with slugs. I live in Newfoundland, Canada, with a damp climate where the slugs can easily grow to six inches in length and I garden organically. We've had great success with copper mesh, which comes in rolls at Lee Valley ( As long as it's in contact with the soil, it sets up a mild electrical current that repels slugs. It must be kept weed-free, but I can now produce cosmetically perfect organic lettuces, where once I grew disgusting slug-filled things that were not fit to eat.
Just thought you might find that useful for your peas.