Author Topic: Xenia Effect in Tomato Seeds  (Read 297 times)

Joseph Lofthouse

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Xenia Effect in Tomato Seeds
« on: 2021-04-12, 04:59:51 PM »
I have read that there is a xenia effect for the size of tomato seeds based on pollen donor. Last fall, I found a possible candidate to test that.

Last spring, one of the potato-leaved Brad plants grew up to be regular leaved, indicating that it crossed the previous summer. I planted the F1 in an area that was surrounded by S habrochaites, S peruvianum, S pimpinellifolium, and [BC with habrochaites cytoplasm). They all have small seeds compared to domestic tomatoes.

When I harvested the seeds, there was a mixture of seed sizes. I sorted them into a population of the largest seeds, and a population of the smallest seeds. I planted the seeds today.

I also planted the smallest seeds from the general populations of Brad, and Jagodka -- as controls. Also planted the largest seeds from Brad, and the general population of Jagodka. The ratios of potato-leaved to regular-leaved Brad will be obvious within a month.

Jagodka was the variety that started the train of thought that lead to the Beautifully Promiscuous and Tasty Tomato Project, because it was so attractive to bumblebees. Therefore, I'm looking forward to watching for naturally occurring hybrids. 
« Last Edit: 2021-04-12, 10:49:07 PM by Joseph Lofthouse »

William S.

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Re: Xenia Effect in Tomato Seeds
« Reply #1 on: 2021-04-12, 06:21:20 PM »
This should in theory work well with Big Hill as a mother. The seeds are large. So crosses with smaller seeded species and varieties should screen out nicely. Like if I planted one Big Hill amongst LA2329 habrochaites.
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Steph S

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Re: Xenia Effect in Tomato Seeds
« Reply #2 on: 2021-04-15, 07:22:29 PM »
Very cool!  And a good thing to know.
One of my F1s from last year had a small seeded pollen parent, and I noticed that the F1 seeds were similarly small.
I wonder if seed size is an indicator of any other linked traits from the pollen parent, during the segregation of next generations.
I tend to pick through my seeds and choose the bigger ones to plant, just to get a bigger seedling.

Joseph Lofthouse

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Re: Xenia Effect in Tomato Seeds
« Reply #3 on: 2021-04-15, 07:33:08 PM »
I tend to pick through my seeds and choose the bigger ones to plant, just to get a bigger seedling.

That was also my strategy when I was growing purely domestic tomatoes. I figured that larger seeds had a competitive advantage, and my tomatoes need every bit of earliness and vigor.

Andrew Barney

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Re: Xenia Effect in Tomato Seeds
« Reply #4 on: 2021-04-16, 12:14:42 AM »
Interesting. I still have a packet of seeds from Fantome du Laos that has unusually small seeds (noticeably smaller than the packet they came from) . I think it was grown there year I was doing the big growout for the various wild tomatoes like pennelli hybrids, peruvianum, habrochiates, pimpinellifolium, cheesmaniae, and galapagense.

I always wondered if they had hybridized....

I guess I should grow them out if they are still viable..

Joseph Lofthouse

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Re: Xenia Effect in Tomato Seeds
« Reply #5 on: 2021-05-01, 04:30:54 PM »
The results are in for Brad.

10 of the small seeds germinated.

18 of the huge seeds germinated.

Every plant that germinated was potato-leaved, indicating that no crossing occurred.

The small seeded plants are generally smaller, and took longer to germinate.


The Brad F2 plants from small-seeded are markedly smaller than the plants from XL seeds. And germination is taking much longer on small seeded.


The small seeded Jagodka germinated well, and some plants out-grew the large seeded plants. I'll continue to watch that population.

« Last Edit: 2021-05-01, 04:37:30 PM by Joseph Lofthouse »

Andrew Barney

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Re: Xenia Effect in Tomato Seeds
« Reply #6 on: 2021-05-01, 05:41:24 PM »

The small seeded Jagodka germinated well, and some plants out-grew the large seeded plants. I'll continue to watch that population.

Interesting results on Jagodka. I wonder if that indicates hybrid vigour. Considering the small seeded seem to be runts in Brad I would think so. Worth watching for sure.

Klaus Brugger

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Re: Xenia Effect in Tomato Seeds
« Reply #7 on: 2021-05-07, 02:10:32 PM »
Here's a picture I made a couple of years ago from seeds that grew on one S. lycopersicum plant: The ones on the left are from pollinations with S. habrochaites pollen, the ones on the right are from open pollination. I'm not sure though if this can really be considered "classical" xenia as within one species. The seeds of course might not be perfectly developed due to a certain degree of incompatibility between the species/genotypes. The hybrid plants, however, were quite vigorous, not really showing pronounced "outbreeding depressing" (other than probably reduced fertility).
Posting the picture didn't work for me (I don't know why, others don't seem to have any problem right now), so here's a link: https://www.instagram.com/p/Ba1vDuQB5SK/