Keeping sweet pea seeds

This year I have kept a lot of sweet pea seeds and planted them in pots at the end of October.  They have all germinated well. My assumption was that they would not breed true because of cross pollination between varieties that were grown quite close to each other.

However, it seems that  sweet peas are normally self pollinated.  While this may suggest that all sweet pea seeds will breed true, there is some doubt whether this is always the case.  My sweet pea plants were not protected from cross pollination - they were "open pollinated".

Now I had always thought that a bumble bee landing on the keel petals of the flower would make the stamen pop out and coat the underside of the bee with pollen which would then be taken to the next flower.  The fact that the stamen and stigma are protected by the keel petals seems to give the flower more chance of self pollination.  When the flower has gone over, pollen has been shed and fallen on the stigma which does not normally protrude from the petals giving a self pollinated flower.

If the sweet pea is self pollinated then it should be quite easy to keep varieties pure because they would only change by mutation. This might give the opportunity for saving seed with some reliability that doing so would produce the same variety as the parents.

Stamens and stigma of sweet pea Lathyrus odoratus (FCIT)

I'm not so sure and will carefully examine  flowers next year to see if this is true.  Unfortunately, I mixed up all the seeds that I gathered this year so I will get a mixture of colours when I plant them out next year.