Friday 6 June 2008
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.)