Blue podded sweet pea

[imgrimmer]

I found some sweet and tender tasting blue podded peas among a blue podded shelling variety 2 years ago.
pods were still sweet and tender in the second generation but only a few pods appeared and plants grew very tall around 1m until the first flower.

What would you suggest to increase harvest and dwarfing the plant? Shall i cross or select (all plants are still very tall this year, means not possible this year) ?

I would like to stabilize it as a blue podded sweet and tender tasting variety with medium height.


Where can I start?

[keen101 (Biolumo / Andrew B.)]

cool project. I would say start with whatever trait you would want most. In your case it sounds like height is the trait you want most and the one you should focus on first. Next would be to find and select a good variety to breed with that has as many of the other traits that you alsos want. For example find a good pea that is the height you want and preferably already has sweet and/or tender pods. Then cross the two and save seeds from every generation if you can an grow out many F2's. By crossing two varieties that both have sweet and tender pods you theoretically should retain good sweet/tender pods in the F1. Then from there you only really need to select for height which you might be able to do even in the seedling stage of the F2's.

Then perhaps you could focus on increased harvest and/or doing more crosses later on. That's my two cents. Pea breeding can take a few years if not many or not long at all depending on how many traits you want to combine and whether the ones you start with already have more than one trait.

[templeton]

imgrimmer,
are you talking about sweet tasting pods, or sweet tasting green peas? I'll assume the latter.
Your blue pods require 3 dominant genes. height is determined by a number of different genes, each of which reduce height by varying degrees. These tend to interact, so multiple short internode genes will give very short plants. Yield is most likely a relatively complex set of genetic interactions, driven by plant vigour to give plenty of metabolites, and flower number to give lots of pods. Numbers of seed per pod might also have something to do with it.
Flavour is complex, sweetness is associated with recessive gene 'r' which delays sugar to starch conversion in the peas, which causes wrinkling of the seed coat as the pea dries. (I suspect eating characteristics are a bit more complex than this, but let's go with the 'official' line)
crossing your blue pod to a green pod will result in 3/4 X 3/4 X 3/4 = 27/64 blue podded peas in the F2, so a bit less than half of the F2s will be blue.
Tall crossed to a short (one gene) will give 1/4 chance in the F2
So 27/256 chance of a short purple podded in the F2 if you cross yours to a short green podded parent. That's about 1 in 10 of the F2s will be short blue podded.
I assume you will cross your nice tasting pea with an equally nice tasting short pea. They should both have the sweetness gene, so all the offspring will also be sweet.
If you grow around 100 F2 plants, you might expect 10 short blue podded peas. but 2/3 of these will not be stable for blue pods - heterozygous.
But there a few shortcuts that allow you to select early.
Cross your pea to a nice sweet short pea - there are lots of varieties available. Choose a parent with purple flowers if you can - this means it will be carrying the A gene, which you want. Grow out a few F1s aiming for a few hundred seeds off these F1 plants.
Next season, sow 200 F2 seeds. Short internodes show up after about 2 or 3 leaf sets - you can cull any seedlings that look tall, and just grow the short ones. Out of 200 you could expect around 50 short plants. I sow into little individual peat pots, so i can plant out the seedlings that have the characteristics I want, without wasting row space.

Many blue podded peas have a purple splash in the leaf axil, so you can select for this as well. You might be rejecting some useful plants if you use this tactic, but any you do select will at least be carrying the A gene that turns on the ability to make anthocyanin.
[Can anyone else remember if axil colour is always present in plants with A gene? I can't recall...]
So using this approach all your F2s will be sweet, all will be short, and all will be carrying at least one of the blue podded genes. So you will now have 3/4 X 3/4 = 9/16 chance of getting the other two purple-podded genes in your plants. Just under two thirds of your short sweet selections should have blue pods. Grow 50 plants and around 28 of them will have purple pods - nice odds.
Hope this isn't too complex a discussion

Stabilising these traits is another discussion. I've gone on long enough.
Thi is a relatively short explanation - have a look at Rebsie Fairholm's 'Daughter of the Soil' blog for a great explantation and photos.
T

[imgrimmer]

Thank you for your answers. Meanwhile I could taste the first pods and found some variation. I will stay on selection for this year, I am too busy to make crossings. Next year I think is a better time for that.