Main stem split off into 5 stems. Normal?

[James Hunt]

Hey there fellow Tomato growers!

I'm growing tomatoes for the first time and in general they're doing ok, despite the Indonesian rainy season. I have noticed on 2 plants that higher up on the main stem, it seems like it has 'fused' with other stems. Is this normal?

My main query though is one container plant whose main stem has split off into not 2 or 3 main stems, but 5! The strange thing is I cannot tell which is the original main stem as they all shoot off at angles. Is this normal? Should I be worried? Will growth/yield be affected? Does it need pruning? If yes, how to prune?

[applestar]

I have seen the fused stem before, but I think the split 5-way stem is just another expression of this genetic anomaly.

From where the anomaly begins, the cells are misprogrammed and the anomaly will continue. Sometimes fusion is minor and result in mega-blooms and mega-fruits, but yours look extreme to me.

Typically the plant will try to live on but when anomaly contradicts normal processes, it will stop growing.

You can see if pruning the stem down to just above a normal leaf will stimulate normal side shoots to grow and carry on as normal plant.

There is one other possibility which is a virus — I can’t remember the name something to do with daisy ..maybe aster... or cauliflower... and I don’t have time to look it up now.

I can’t remember if tomatoes get this disease either. Maybe this is enough for somebody else to recall the details.

If it’s a disease, the new side shoots will also be affected I think.

[applestar]

Aster Yellows is what I was thinking of. So far, I have found multiple notations that tomato is susceptible but the symptom descriptions don’t seem to match. You may recognize similarities in your plants though. Here’s one reference — you Might see why I thought of it from photos of other plants with this disease:

Aster Yellows
https://wimastergardener.org/article/aster-yellows/

[James Hunt]

Thanks for posting Applestar

I have never heard of Asters Yellow. I checked out that link and tomato is on the list of vegetables it can affect. I'll keep an eye on my plants. It's only affecting those 3 tomato plants - I have around 8 others at a large size (plus many more seedlings) which are all growing normally. The 3 in question seem healthy enough with no visible signs of disease or infection, but we'll see what happens over the next few months. The rainy season should start trailing off in a month or so and we will have some much needed direct sunlight.

I don't think topping or pruning these plants will do anything so I'll let them be and see how things unfold.

[James Hunt]

I have just found out why the stems fused together. It is called fasciation and often happens with tomatoes and other plants. It is nothing to worry about, so all good. Let's hope we all get a bumper crop

[applestar]

Yes, it’s true that this happens as I mentioned before, but sometimes when it’s more than just two stems fused, the bunching effect and competition for the nutrients and water funneling through just one area with passages that are sometimes constricted due to the fusing as well as the multiple overlapping leaves competing for the sunlight can create limiting effect that actually is detrimental to growth.

(...bah! I just woke up and I’m typing this without filtering from brain-speak. Basically because they are constricted and bunched together, the “vessels” in the stems might not be able to transport nutrients and water correctly. And because they are multiple stems stuck together, there are more than usual number of leaves growing together in same space that shade each other as well as blocking airflow — if fungal issues are a problem in your garden.)

I was speaking from experience above — I had one seedling that seemed to fuse together and terminate in a gigantic mega bloom (kind of like a sunflower) — it Stopped growing and tried and successfully fruited on that single fused/fasciated blossom (actually I helped it by buzzing with an electric toothbrush), but nothing else grew — no Side shoots, leaves, until the fruit had ripened and was removed, and the fused section pruned down to lower healthy stem. Then it grew rapidly into a normal plant. This was indoors with less pest and disease pressure to attack the weakened plant.

I have also had excessively fasciated blooms on non-competition (not genetically selected for biggest tomato competition) plants which did its best to mature the fruit that set on a megablossom, but the effort took away from the rest of the plant and it rapidly succumbed to fungal issues that were plaguing the garden.

On the other hand, I have grown seeds obtained from competition lines and they do grow gigantic fused fruits without side effects. I think being selected for this trait over generations, the weaker defective performers are culled out of the line.


IMHO, however, it IS always fun to see what happens when anomalies occur, so if you are going to let these grow, please keep us posted on their progress. I’d love to find out how they will grow. (You are definitely not seeing the symptoms of Aster Yellows, then? If you are, it would be prudent to at least isolate them from the rest.)

[applestar]

...also, the “main stem split in 5” seems like a different sort of situation. Are you also going to see what happens with it without intervention?

[James Hunt]

Hey Applestar,

Regarding the fused stems plants, yes I am going to leave them be. They have both just started to form flowers at different heights so am looking forward to tasting them.

Regarding the plant that split off, yes I am going to leave that be too. They plant has also just started to form flowers. One variety is Rewako F1, but not sure of the other varieties as I just used seeds from a bought tomato.

Incidentally, I have just planted a variety of determinate and indeterminate toms including beef toms, red and yellow cherry toms, indigo toms and some yellow pear toms. Hopefully, they all mature and fruit