Genetics or environment?
 

Here's a photo of fruit from a Boar's Hoof plant. I grew two plants of this variety this year in different garden beds. One plant yielded fruit with this very distinct mustard/green shoulders type, the other with no/very subtle green shoulders. At first I thought I found an interesting variant/mutant, but a few weeks later I noticed the a similar pattern in the seemingly related Evan's Purlple Pear, with again two plants in the same different beds. My question: is this shoulders coloration related to differences in the micro-climate, or a genetic variant. I saved seed from both to give a definitive answer next summer, but thought someone might be able to speak from experience.

It's a result of the chlorophyll not being broken down, of course, but I'm not sure why that happens. I tend to see more of it when there isn't enough leaf cover and it's hot. Maybe there was more reflected light in one bed or something.
Interesting question.

That is exactly what I am seeing this summer, with the hot, sunny conditions on plants with not a lot of foliage cover over the fruit. I am convinced it is the conditions. I haven't tried shading the fruit or the plants overall. I wonder if that would cure this?

Steve S :?!?:

if you Google tomato diseases green shoulder, you will get quite a few results.
Goodwin hit it right on the money, and its caused by lack of leaf cover.

Here is info on it:
Yellow/green shoulder

area affected is exposed to sun, and chlorophyll fails to change as fruit matures.

SteveS we posted at the same time but edited this in: Shade should help it.

No differences in the two seed lots I grew out this year, so in this case there does not appear to be a genetic component. I also found a useful discussion here: [url]http://franklin.extension.psu.edu/Horticulture/Articles/Yellow_Shoulder_on_Tomato.pdf[/url]

In what is probably a magnificent manifestation of this same syndrome, I found this remarkable fruit with golden shoulders this summer.

I have lots of yellow shoulders and uneven ripening issues in my greenhouse tomatoes this year, especially on my heart-shaped varieties.

But all hearts in my container garden did not have these issues this year.

I have to conclude it is the difference in growing conditions: as we had some extreme temperature fluctuations this summer, going from cold to scorching hot very quickly several times, and as a result, I could not control soil moisture very well in my GHs, plus I neglected to add more manure to the GH soil half way through the season. This resulted in poor fruit set, poor foliage cover, and some less vigorous plants in the GHs. On the opposite, the container tomatoes grew huge and vigorous (lots of mushroom manure there), yielded high, and had more asserting taste, whether it was sweet or acidic.

So there is certainly something there in the growing conditions...

Tania

Its also linked to soil potassium


[URL]http://www.oardc.ohio-state.edu/tomato/managingcolor.htm#color[/URL] disorders of tomato.

I am 'flipping the coin' on this one. Yes, it appears to be a chlorophyll issue. In this thread it has been suggested that there was not enough leaf cover to protect the fruit. Here is where I flip the coin. The [B]leaves[/B] convert sun into chlorophyll. Regardless of the fact that the leaves were not providing shade to the fruit, there were [B]not enough leaves[/B] on the plant to do the conversion in the first place. Please, correct me if I am wrong. The fact that the fruit was exposed to sunlight should have little/no bearing on the matter. The fact that the fruit was exposed to the sun indicates that the plants had sparse foliage. Heavy foliage converts a lot of sunshine into a lot of chlorophyll, and sparse foliage does not.

The chlorophyll in the leaves convert sunlight to sugar. A tiny bit of light is needed to induce chlorophyll production (like potatoes turning green or yellow grass growing in the dark under a discarded board). Part of what is going on here with the tomato is heat (greater where there is sun exposure) deactivating the ripening mechanism that breaks down chlorophyll and builds the red pigment.

Low Potassium.
-d

Low potassium leads to... green shoulders? colored shoulders?

can manifest green yellow white or oarngeish. also leathery look is common.
-d