Brix over time

[Frosti]

Hey everyone,

this season I got myself a refractometer to more accurately select the plant with the sweetest fruits for my current breeding line, and I thought some of you might find my results interesting, so here they are ...

A quick background:
This is a multiflora line with the original goal of a dwarf multiflora plant, but the best tasting plant last year turned out to be a bit of an oddball. Not really a dwarf, but also not quite tall enough to not call it a dwarf. Anyway, the offspring of this plant also turned out to be very compact and healthy but since I crammed 2 plants in each 40L pot and I pruned them to a single main stem they eventually grew to a normal height. There are 18 plants in 9 pots, all next to each other at the same location. This is what my jungle looks like today, after neglecting it for quite some time already:

jungle.jpg

These are my brix measurements over the last 4-5 weeks:

brix_1-23-F3_20240907.png

I did not expect them to fluctuate this much. I also think the brix took a downward turn when the weather got too hot for tomatoes (about 30°C).
Of my 18 candidates only three are still in the race for next season. The plant with the highest average brix of 12.5 is 5-24. This is also the plant with the highest floor with a minimum brix of 11.9. Its hightest peak was at 13.4, while 18-24 peaked at 14.0, but also plummeted all the way down to 10.2 ...

just for comparison's sake, one of my all-time favorite cherries is "Mexican Honey" which had a brix of 10.5 this season, while "Großes Birnchen", which in all likelyhood is "Yellow Submarine", reached 11.1.

All three remaining contenders have very good taste, so which one would you choose?

[Doffer]

I have noticed that the Brix can also vary greatly per fruit. For example, I had a beef plant that had fruits with Brix 5 that tasted normal and fruits with Brix 8 that were super tasty.

[bower]

Love that sweetness jungle! I've never measured brix, but I do gravitate towards sweeter fruit. Sweetness varies depending on ripeness, which can be difficult to judge. Sweetness may also be affected by water uptake, as many have commented over the years, overwatered plants don't produce tasty fruit. So a period of more rain, for example, could cause variance. And as you mentioned, heat has an effect as well, on ripening and taste development, as does cold.
Since you asked, I would choose the plant with the least variance in brix, that is your red line, to grow forward, given that all have equally excellent taste. But I would save seeds from all of the contenders just in case!
A plant that does best at maintaining its taste in variable conditions, is going to be the top selection IMO, unless it has some other defect in production or quality that can't be eliminated by selection at the next round.

[Frosti]

Love that sweetness jungle! I've never measured brix, but I do gravitate towards sweeter fruit. Sweetness varies depending on ripeness, which can be difficult to judge. Sweetness may also be affected by water uptake, as many have commented over the years, overwatered plants don't produce tasty fruit. So a period of more rain, for example, could cause variance. And as you mentioned, heat has an effect as well, on ripening and taste development, as does cold.
Since you asked, I would choose the plant with the least variance in brix, that is your red line, to grow forward, given that all have equally excellent taste. But I would save seeds from all of the contenders just in case!
A plant that does best at maintaining its taste in variable conditions, is going to be the top selection IMO, unless it has some other defect in production or quality that can't be eliminated by selection at the next round.

This is my current reasoning as well. I took care to always water the plants equally. Regarding the ripeness, this was another revelation for me. In the past I always thought overripe fruits were the sweetest while the texture got worse. Now I realize that peak sweetness and flavor is present when the fruits are ripe but not overripe.

I'll keep measuring the brix up until the end to see how the contenders fare in all conditions.

[Frosti]

I have noticed that the Brix can also vary greatly per fruit. For example, I had a beef plant that had fruits with Brix 5 that tasted normal and fruits with Brix 8 that were super tasty.

While I did notice some variance between the fruits on the same plant, it was mostly +- 0.5 brix iirc. This is why I chose to measure quite often, which is easier done with cherries than beefstakes of course.