Round tomato varieties throwing a plant that produces hearts

[Acer Rubrum]

So what's the deal with this? Do all round varieties just occasionally pop out a plant that gives hearts? Is the heart shape usually stable in that case? I know it was for Cherokee Purple Heart.

I have a round of a newer variety (Sweet Splash Electra) and one of this year's plants is producing hearts. I realize that this could be a bit of residual instability since this variety was only released a couple of years ago, but I've heard of heart shapes randomly appearing in other varieties as well. Just curious about other people's insights on this.

Also, the picture of the round tomatoes is from when the plants were younger, so that's why they're smaller. The size seems consistent between the rounds and the heart shaped one.

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[peebee]

I had an Odoriko once that had hearts, I saved seeds but all 3 I grew out were rounds. I don't know why a plant produced hearts that year but they sure looked nice .

[pondgardener]

@Acer Rubrum I seem to remember reading on another forum about certain environmental stresses that caused production resulting in hearts from seed saved from round shaped tomatoes.

[bower]

That's a gorgeous heart shape! Very classic, I mean the "sun" and "ovate" oxheart type shape.
But those are not the only 'hearty' genes. I don't think the genetics of pointy ended fruit has been made super clear, though I haven't read about it for quite awhile. There are multiple genes involved. Some are suppressed by other shape genes, some are activated by gene expression in specific environmental conditions. So it is possible, with that type of gene present, for a plant to throw some heart shapes in certain conditions. That could explain peebee's experience with Odoriko.
As for the fruit that seem to mutate into a heart form which is passed on to offspring, it could just be that an unstable gene was suppressing the heart shape from being expressed. Or it could be a mutation in the suppressor gene, or in the shape gene itself. Without some high tech science to answer the question, we'll never know.

[Pippin]

Seems to me that the variegated trait is also expressed in the heart shaped fruit. The round ones in the picture have ”green stripes” but the hearts seem to have ”white stripes”. Is that so? I thought that the variegated was supposed to be expressed only in the leaves and stems. Would be interesting to know what colour striping there is in other fruits and plants if there are many.

Not claiming that the ”white stripes” has anything to do with the heart shape, just pointing out.

I would save some seeds from the heart fruit plant if the tomatoes tastes as good as the round ones.

[patihum]

The Sweet Splash series selection that ended up being named Electra did indeed throw some hearts at the F4 stage in 2017 but wasn't seen in 2018.

[Shule]

Round fruits (and even other shapes) can sometimes be heart-shaped because of the growing conditions, without it being genetic.

I've had a heart-shaped Early Girl F2 (or maybe it was an F3). At least several fruits on the plant were oxheart-shaped.

I've also had a heart-shaped Sheboygan. Just one fruit on the plant was oxheart-shaped.

Neither was genetic. I grew the seeds to find out.

A heart-shaped sport could be genetic, though. It's hard to tell the difference until you grow them to find out.

There's also the possibility that it's a cross with an oxheart.

[Acer Rubrum]

Thank you for your comments. It's taken a while for me to get back to this thread since July has been busy with family events and shows no sign of slowing down.

The stripes on both the round and heart shaped tomatoes end up being white. It's just that the round in the picture is less mature. When ripe, they're yellow with white stripes. You have a look close to see the stripes though.

Patihum - I didn't know that about there being hearts in the Sweet Splash lineage. I bought my Sweet Splash Electra seed in late 2020 and grew it out in 2021. These plants are from seed saved from my 2021 plants.

I don't think these are a cross with an oxheart because the variegation, plant size and color of the fruit are the same. A cross would likely have resulted in a bigger plant, little or no variegation, and probably a red tomato. But I'm definitely planning on saving some seed from these hearts. I've got some fermenting right now actually.

[Shule]

@Acer Rubrum
I don't know about all variegation, but I've heard that at least one of the variegation traits is inherited from the mtDNA, which would seem to mean that the matriarchal lineage would still be variegated, every time, and the patriarchal lineage would never cause nor remove variegation. (mtDNA is passed from the mother to the child in tomatoes, if I understand that correctly.)

@Bower might have some insights on this. Bower, see the previous post.

[bower]

I agree with Acer Rubrum, unlikely to be a cross. I'm pretty sure the variegation is recessive so that alone would rule out any cross. It does sound like the heart genetics were lurking in the line, and just happened to get together as those more subtle characteristics continued to sort out. Or possibly a single mutation that caused this to be expressed. I really hope they're stable, it's such a pretty shape!

[mama_lor]

Abundance of certain plant hormones will lead to elongation of the fruit.

[karstopography]

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These two tomatoes are big beef. Not really the shape that big beef normally are, but a number of the recent fruit has been shaped like this.
I’ve noticed fruit size and shape of the fruit on a number of tomatoes varieties tend to change over the course of the season. Really don’t know what drives the fruit size and shape changes, but I’d suspect the weather plays a role.

[Tormahto]

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These two tomatoes are big beef. Not really the shape that big beef normally are, but a number of the recent fruit has been shaped like this.
I’ve noticed fruit size and shape of the fruit on a number of tomatoes varieties tend to change over the course of the season. Really don’t know what drives the fruit size and shape changes, but I’d suspect the weather plays a role.

That shows the classic "perfect" blossom scar, to me, being but a tiny dot. Any large blossom scar has never produced a heart shape, in my garden, on globes and beefsteaks.

[bower]

There is a type of 'pointy' gene that is present in some beefs but is not (normally) expressed in the shape at maturity, except as you pointed out @Tormato in the 'perfect blossom scar'. The pointy gene tends to produce more regular beef shapes, and is one reason I have kept or tried to keep the pointy gene in my breeding lines. It can sometimes be detected in the immature fruit early on, and certain weather conditions cause heart-like shapes. But I've never seen environmental effects cause every fruit on the bush to be heart shaped. I think that a consistent heart shape is more likely to be a type/combination of heart genetics that is consistently expressed (more or less! since heart shapes also vary).