Parthenocarpy !

[veggiechicken]

I need some help with big words that I don't understand, please!

Apparently, some courgettes, cucumbers, tomatoes are "parthenocarpic" - they set fruit without the need for pollination. Any seeds produced are infertile.
(For ease I'm abbreviating "parthenocarpic" to P)

P varieties can be all-female (gynoecious) or produce male & female flowers (monoecious).

Can anyone tell me how a P, all-female, cucumber/courgette can produce seeds for sale?

They're not all F1s either as Real seeds sell "Legend" tomato which also doesn't need pollination

Sorry if this doesn't make any sense. I'm totally bamboozled by the idea. Need someone intelligent to help me please

[Thelma Sanders]

I'm no scientist, but from 5 years of growing Partenon courgette, I think that the flowers are capable of setting fruit whether they are pollinated or not.

The pollinated ones can grow quite long, get fat and turn a paler colour after a while, and get seedy - whereas the non-pollinated ones seem to stay slimmer and a darker green.

So you can get viable seed, but only from the pollinated ones

[Penellype]

I've noticed this with Shirley tomatoes grown indoors. Some of the tomatoes develop but are much smaller than the others and contain no seeds at all. I think Thelma is right that they do not need to be pollinated, but if they are pollinated they will make seeds which can then be grown.

[veggiechicken]

Thanks Both. I'm finding this really interesting - and confusing
Both Partenon and Shirley are F1s. Has anyone tried growing either of them from saved seeds.
Shirley doesn't claim to be P - maybe its partially P, if you're finding seedless tomatoes, Penellype.

[alldigging]

I assume they 'can' set seed but don't have to be pollinated to make fruit.

Maybe they're self-infertile? So they need another plant to provide the pollen - that's basic incompatibility which apples do - so they need another type to pollinate (Although then you don't get the f1 guarantee... so to f1 guarantee they must be pollinated by a boy plant of the same type... and so anyone producing seeds needs some boy plants and some girl plants)


Dioecious plants is how it's referred to in module 2 of the bbka stuff.

https://en.wikipedia.org/wiki/Categoryioecious_plants

We look at it from a cross pollination point of view - and most plants like to cross pollinate.
Being monoecious, or dioecious, or exhibiting protandry or protogny are ways plants ensure they are cross pollinated rather than self pollinated. (And there are all sorts of bizarre things flowers do to make sure pollen gets spread about - some spiral plants I think I read about in an Attenborough book.

[Thelma Sanders]

Inside the plant ovary there are lots of potential seed, not all need to be fertilised for a fruit to set - that's why you ferment out tomato seeds for saving. The non-viable (unfertilised) seeds float up in the scum for removal, good ones sink for drying.

If you start with an f1 you'd not get the same thing if you did grow seeds from it - so doubt the seed would be worth saving.

[Penellype]

Not tried growing Shirley from saved seeds because being F1 the one thing you would not get is Shirley!

[Bigmallly]

Real seeds sell Legend Tomatoes which apparently are parthonocarpic sooooooooo, if they don't produce seeds, how can they sell them?..........

[Zelenina]

Real seeds sell Legend Tomatoes which apparently are parthonocarpic sooooooooo, if they don't produce seeds, how can they sell them?..........

This seems to be the explanation, Mallly

"Early, high quality, richly flavored, fruits are round, red, and seedless. Only at the end of the growing season does this shy seeder produce seeded fruits."

which I found here: https://www.nicholsgardennursery.com...ic-pid922.html

[Bill HH]

I have wondered the same thing about seedless grapes and pipless oranges.

[marchogaeth]

Hurray a really interesting thread - made me realise how much I've forgotten (again). I found this slide show really informative. It's rubbish as a slide show! Imagine all that info on a slide - might as well read a book!

Before anyone throws up there hands in horror at the comment about tomatoes, I think this is referring to the difficulty many producers in large glass houses have in getting good fertilization without insects (or through stimulation with brushes by hand), apparently tomato yields are higher and more tasty if the fruit are pollinated by insects (yes even though they are self-fertile). This is what has lead to the use of "boxes of bees" in these places and all the concerns they have caused our native species. However, feel free to educate me further if you know more.

[Zelenina]

I think the problem with tomatoes, marchogaeth, is more to do with very high summer temperatures that interfere with pollination, as explained here:

“Tomato plants can tolerate extreme temperatures for short periods, but several days or nights with temperatures above 90oF (daytime) or 72 oF (nighttime) will cause the plant to abort flowers and fruit (Fig. 2). At these temperatures the pollen can become sticky and nonviable, preventing pollination from occurring and causing the blossom to dry and drop. The relative humidity also plays a role in pollination, high levels (>80% RH) (which we had and will have this week) during pollen shed will cause the pollen not to be released properly resulting in poor or incomplete pollination.”

That’s an extract from an article by Jerry Brust, IPM Vegetable Specialist, University of Maryland. Read the full article here High Temperatures Could Mean Poor Fruit Set in Tomatoes | Weekly Crop Update – Cooperative Extension in Delaware

My runner beans last year had the same problem. Lots of flowers all summer but no beans set until the weather turned cooler and wetter in the middle of August. I've seen new varieties of runners advertised as being able to set beans without pollination to overcome this problem.

But I guess that might not be such a big problem in Wales

[Jungle Jane]

I don't know much about seed breeding etc but legend tomato was developed by Jim Myers and James Baggett,so they can make seeds have some blight resistance & do things to make it infertile maybe? So not involving a hybrid,it's not an f1. But careful breeding can produce what they want. If you go to the biography on Jims page he says "I have developed and released 13 dry bean, one green bean, and two tomato cultivars. One tomato cultivar (co-released with Dr. J.R. Baggett) is ‘Legend’, an early, large fruited, parthenocarpic, determinate slicer with late blight resistance."

Jim Myers | Department of Horticulture | Oregon State University

.

[marchogaeth]

Interesting Zelina. You could be correct or maybe it's another reason why parthenocarpy in tomatoes could be useful. Dave Gouloson mentions the whole glass house tomato thing in his book on bees which is where I picked it up. He was especially focusing on Australia I think which presumably could have the problems you are writing about. I was just extrapolating because I though people might be thinking "but tomatoes are self- fertile".

[veggiechicken]

Thanks for all your replies!
Why am I trying to found out more about P?
Here goes - please tell me if my theory is flawed

If my first sowing of toms, cucumbers and courgettes next year is P varieties, they should produce earlier than non-P because they don't need pollination so aren't reliant on bees/warmer weather. Also, if those P varieties are all-female, they won't even produce male flowers (which always seem to come first).
Similarly, if I do a late sowing of these seeds, I may be able to catch a late crop and extend the season.
So my vague plan is to sow P seeds in Feb/March followed by normal seeds in April/May; then back to P seeds in August.
Will it work, O wise ones?