Author Topic: seeds from parthenocarpic fruit  (Read 618 times)

Diane Whitehead

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seeds from parthenocarpic fruit
« on: 2019-12-16, 12:29:43 PM »
Some very early tomatoes are seedless but produce seeds later.

What about cucumbers?  I'm reading the latest Whole Seed Catalog, and Baker Creek is enthusiastic about China Jade cucumber, their best tasting one.

Do they produce fruit with no seeds if they are kept in an insect-free greenhouse, but perhaps have seeds if they are grown outside where they can be pollinated?
Victoria, British Columbia, Canada
cool mediterranean climate  warm dry summers, mild wet winters,  70 cm rain,   sandy soil

Ferdzy

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Re: seeds from parthenocarpic fruit
« Reply #1 on: 2019-12-16, 12:35:49 PM »
Yes, my understanding is that if they are fertilized they will produce seeds. See this page:

https://seminis-us.com/resources/agronomic-spotlights/understanding-flowering-habits-cucumbers/

"Parthenocarpic varieties are seedless, or nearly so (Figure 3), and the fruit develops in the absence of fertilized seed. These varieties can produce seed if pollinated. Therefore, parthenocarpic varieties should be spatially isolated from other types of cucumbers to keep the fruit seedless.3"

Diane Whitehead

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Re: seeds from parthenocarpic fruit
« Reply #2 on: 2019-12-16, 01:58:49 PM »
OK  So how does it work if I want to save pure seed of that variety?  Do the parthenocarpic plants produce some male flowers?

Victoria, British Columbia, Canada
cool mediterranean climate  warm dry summers, mild wet winters,  70 cm rain,   sandy soil

Ferdzy

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Re: seeds from parthenocarpic fruit
« Reply #3 on: 2019-12-16, 03:34:11 PM »
Diane, I think so.

I wrote about Telegraph Improved a few years back and noted that William Dam (the company from whom I had got it) made a point of saying the male flowers should not be removed, as the variety was not parthenocarpic. The implication would be that if you are growing a parthenocarpic cucumber, you need to remove the male flowers to prevent them from fertilizing the female flowers and producing seed.

https://seasonalontariofood.blogspot.com/2013/08/telegraph-improved-cucumber.html

Lauren

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Re: seeds from parthenocarpic fruit
« Reply #4 on: 2019-12-16, 04:26:19 PM »
I accidentally planted one this year. I pollinated by hand from the male flowers on both plants and got no seeds, so it's probably a combination.

Steph S

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Re: seeds from parthenocarpic fruit
« Reply #5 on: 2019-12-18, 05:11:55 PM »
Interesting...  When I grew Diva I noticed that they had rather a lot of male flowers.   I didn't know that was normal.    Another parthenocarpic cucumber I grew before (Passandra) had all female flowers, don't recall seeing any males at all.

In tomatoes, Cold Set produced lots of normal seeds all season, but Siletz was seedless until the end of season. 

So it may be a lot easier to get seed of some parthenocarpic varieties than others.

Walt

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Re: seeds from parthenocarpic fruit
« Reply #6 on: 2019-12-19, 09:37:59 AM »
When I was breeding tomatoes back 1971981, sha-pat was the only parthenocaorpic gene known.  sha-pat stands for short anther-parthenocarpic.  I got it from Tomato Genetics Cooperative.  It was effectively male sterile under most conditions though the seed bank said they opened the anthers and manually selfed it. 
Under my conditions, just south of the Sahara, it never made usable pollen nor did it set seeds.
I assume this is not the gene being used here.  Though selection in a broad based population for fertility might have been effective.

Steph S

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Re: seeds from parthenocarpic fruit
« Reply #7 on: 2019-12-19, 10:06:24 AM »
I have seen some degree of parthenocarpy in several OP's or breeding lines, where in extreme heat seedless fruit are still produced, but may be reduced in size to a greater or lesser extent.   It's a useful trait - from the pov that some crop is better than none.  But new parthenocarpy genes are still being identified, which don't reduce fruit size.

This is from recent work on the genetics which identifed yet another gene:
" There are currently five parthenocarpic tomato resources that are controlled by eight different parthenocarpic genes—‘Soressi’ and ‘Montfavet191’ (pat), ‘Severianin’ (pat-2), ‘RP75/59’ (pat3/pat4), ‘IL5-1’ (pat4.1/pat5.1), and ‘IVT-line1’ (pat4.2/pat9.1) (Gorguet et al., 2005, 2008). Genetic linkage maps have been constructed for five of these genes, pat, pat4.1, pat4.2, pat5.1, and pat9.1 (Beraldi et al., 2004; Gorguet et al., 2008), and pat-2 was recently mapped to chromosome 4 and found to encode a zinc finger homeodomain protein (Nunome et al., 2013)."
https://www.jstage.jst.go.jp/article/hortj/86/4/86_OKD-042/_html/-char/en

Ellendra

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Re: seeds from parthenocarpic fruit
« Reply #8 on: 2019-12-20, 11:14:59 AM »
One of my seed growing assignments last year was for a parthenocarpic cucumber variety. It was my experience that they produced fruit with or without pollination, but when they were pollinated they produced seed. Not nearly as much seed per fruit as most cucumbers, but enough to maintain the variety.
Harsh winters, high winds. Temps on the edge between zones 4 and 5. Steep, north-facing slope. Soil is high in clay and rocks. Fast draining, which is a surprise for clay soil. Indicates a sandy/gravelly layer underneath.