Tuesday, April 17, 2012

Purple Pea Flowers: Cross Pollinating With Purple Peas

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It's getting dangerously close to the end of my second apprenticeship here at Stone Barns Center.  I have seen and worked on incredible projects from my first days with Matt as a green volunteer, still believing that carrots grew in the back of a supermarket, to the Captain handing me the keys to the greenhouse back in December.  Relationships with the space, the plants, myself and others. Exploring internally, emotionally pushing myself through false walls and expanding into a capacity I never realized I had both physically and mentally.  This journey has been one of unlearning and learning, hiding from demons and slaying them face to face.  I hold each one of these experiences close to my heart.  Experimenting with these beautiful pea varieties has definitely been one of the more all-encompassing learning experiences on the farm.  I propagated them, built the trellis, transplanted them and have watched them grow.  Over the last few weeks, they finally began to flower and that means it's time for us to cross pollinate the two purple varieties (Caruthers pea and Sugar Magnolia pea) with the green Oregon Giant snow pea. In this process, we select a host or female flower, which will remain attached to the plant we would like to produce a seed pod.  The male flower will be plucked off of another plant and used solely for its pollen.  Peas have what is known as a "perfect flower" which means it has...



both male (stamen) and female (pistil) parts.  A perfect flower will pollinate itself if left unattended, which will produce a seed pod, so timing is a major part of the pea breeding process.  This makes cross pollinating even more interesting because we end up developing an eye for finding ripe male flowers and immature female flowers that have yet to produce pollen.  Below are some good examples of mature flowers that can be selected to play the role of male.  We are looking for something ripe with pollen, but not too old that it has already opened and pollinated itself.   As for the female,



we are looking for an immature flower that hasn't created pollen yet. The line is extremely thin, but after a few trials it's amazing how clear it becomes.

Here is a flower to play the role of female as it's still immature.



As a reference, this one below is a little too mature to be the female.  When we open this flower, we find that the pollen has already matured and pollinated the stamen.  A good trick is to check the outer leaf petals, if they are overextended, as they are below, than it has most likely already been pollinated.  



This young purple flower where the outer petals haven't opened is ideal.


We then peel back each layer and pinch off this tiny outer casing that covers the pistil (female) and the stamen (male).


Unlocking this case we see that the pollen is not mature, which is the right time to pinch off the yellow stamens so that there is no chance of any pollination.  



Once the female is exposed and ready for pollen, the semi-mature male flower is selected and pinched directly off of the plant since it will not be needed after pollination.


In the same way the purple flower was opened, we reveal the dusty, golden pollen from this white Oregon Giant flower.




Then we put the pair together.

Warning: The following image may be inappropriate for children under the age of 18

And there it is...


Once the pistil is fully coated with pollen from the chosen male flower, feel free to eat the male.  Pea flowers are delicious by the way.


Because we are running this experiment in the greenhouse where there are very few pollinating insects i.e. bees or butterflies, at this time of year, we don't need to cover the pistil after we are done.  If this was done out in the field, it may be a good idea to use a gel capsule or other cover to prevent any further cross pollination that can occur from insects, wind or other external factors that may be out of our control.


Finally, we label the plant to make it easy for us to identify the correct pea seed pods.  Interestingly enough, the visual representation of the pea pods wil be unaffected by this procedure.  Purple flowers will produce purple pods and green will produce green, but within the pods, the seeds will contain a variety of genetic permutations from the two different parents.



Now we wait.  Eventually, we will select the most visually appealing varieties from there and continue on three or four more times until we can identify and stabilize the variety we are hoping to find, a sweet, tender, purple, snow pea similar to the taste and texture of the Oregon Giant, but with the deep purple color of either Caruthers or Sugar Magnolia.


Follow the story of the Stone Barns Center purple pea project here:


5 comments:

  1. Interesting, Jason!! Very interesting!
    By the way, I like the blog!!!
    Smiles from Rio de Janeiro! :)

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    1. Thanks! It's great to hear from you. Hope all is well in Brazil!

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  2. I really appreciate the time you took to share this. The dialogue and pictures are great! Thank you.

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    1. Thank you for the comment, please come back and join us. If you have any questions about sustainable ag, farming, food or anything else that may be of interest, let us know.

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    2. Jason,
      Great pictures of the pollination process, well done! I've been working on several lines of coloured snows and snaps, you might like to check out my progress at http://templetonsmedelania.blogspot.com.au/. One problem we've been discussing at homegrowngoodness is getting a good flavoured snow from a purple parent - the flavour genes are a bit harder to work with than the colours!
      cheers, and best of luck with your progress.
      T

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