Genetics Math

[Boutique Tomatoes]

That's what I'm trying to work out. Unfortunately I believe experience is probably a better teacher than statistics at some of this process, so I'm hoping to learn from those breeders who've been doing this on a larger scale.

If I do a pre-screen well before transplant for antho in the leaves and stem I presume that will let me select for atv/atv at that point. The connection with Aft isn't completely clear to me yet, but my current understanding is that this is a useful early screen that can reduce the sheer number of plants required when selecting for anthocyanin accumulation.

So, if I started 160 seeds and selected the expected 25% showing strong antho at the seeding stage that would have me planting out 40 plants looking for the Aft + elongated cherry combination and I would presumably find 2-3 of them in that population. I'm not sure if in practice that is too few or if that's overkill, but that's where my current thoughts are given where the math is leading me.

For the currant/small tomato types it would appear to require much smaller grow outs if I start with a dark antho cherry and cross to the various currant/small cherry types I can apply the antho foilage screen early and have a good chance of finding strongly antho types in the remaining population. Then the subsequent generations require larger numbers looking for the less easily quantified factors like fruit size, set, plant vigor, etc.

I'm intriqued by reports that the Sungold taste and foilage smell seem to be linked, which would be another useful early screen for crosses with parents descending from a Sungold cross.

[maf]

Originally Posted by marktutt

So, if I started 160 seeds and selected the expected 25% showing strong antho at the seeding stage that would have me planting out 40 plants looking for the Aft + elongated cherry combination and I would presumably find 2-3 of them in that population. I'm not sure if in practice that is too few or if that's overkill, but that's where my current thoughts are given where the math is leading me.

This is exactly how I would do it.

With the two genes you are looking for you would be able to easily find the 2 or 3 segregates that are homozygous for both target traits, but do not neglect the heterozygous expressions either. With the two traits mentioned the heterozygous expressions for both should be easy to spot, and should be screened for taste just in case one of them contains an invisible combination of superior tasting genetics. I find many so-called recessive traits very easy to spot in a heterozygous expression, and these two you are looking for are only partially recessive so will be very easy to spot.

So, after you have selected for atv at seedling stage your 40 plants would include 5 that are homo for Aft and hetero for sun (or el or whatever), 5 that are hetero for Aft and homo for sun and 10 that are hetero for both, in addition to the already mentioned 2.5 (2 or 3) that are homozygous for both traits. That leaves 17.5 plants that either inherit one or the other or none of your desired traits and can safely be culled when they are old enough to phenotype, which would be well before the ripe fruit stage. If this was me doing the growout I would plant out twice as densely as normal and cull almost half the plants before first ripe fruit.

Out of the 22.5 remaining plants I would select first for flavour rather than preferring the homozygous expressions of the two genes, because those will be easy to segregate out in the subsequent generations.

[Boutique Tomatoes]

Ahh, that sounds like experience kicking in. What was puzzling me was just having the 2-3 plants that were homozygous at F2 didn't seem like that would give me great odds of finding the combination of the right look along with flavor,vigor, etc.

With 22.5 (the half plant I guess I can top ) to select from the odds of finding a winner look much better.

[maf]

Yep, you don't have to immediately select for black or white, you can choose gray if you like and do the fine tuning later. As long as you can spot the desired phenotype you know you have something to work with.

[Darren Abbey]

Originally Posted by Worth1

I'm going to chime in here and say something that has been bothering me.
It is more of a question.

How can I be so adept at electronics, how to build things. hydraulics and so forth.
Many of these things I mentioned baffle most people but it has always came to me naturally.

I can see everything in my mind before it is complete and have all of the problems worked out.

But the above conversion has me totally lost the more I read the more it hurts.
Just wondering.

Worth

I'm on the opposite end. Genetics is second nature to me... but I keep getting confused in electronics because the convention for electric flow is opposite of what the physics says is actually happening. And though I've studied hydraulics from a physics standpoint, I have no intuition whatsoever when it comes to application.

[Redbaron]

Originally Posted by Darren Abbey

I'm on the opposite end. Genetics is second nature to me... but I keep getting confused in electronics because the convention for electric flow is opposite of what the physics says is actually happening. And though I've studied hydraulics from a physics standpoint, I have no intuition whatsoever when it comes to application.

Very good point. Try reading a schematic that includes both electrical and electronic conventions in the same diagram!!!!!!

[Fusion_power]

How to keep a nerd occupied for hours. Ask this question.

Does electricity flow from negative to positive? or from positive to negative?

DarJones

[Redbaron]

Originally Posted by Fusion_power

How to keep a nerd occupied for hours. Ask this question.

Does electricity flow from negative to positive? or from positive to negative?

DarJones

If he ever does come back with an answer, really confuse him by asking him, "What about hole theory?"

[Doug9345]

Then ask about an ionized gas where there really are both positive and negative charge carriers.

[Dutch]

These questions get easier to figure out once you understand that lightning travels from the ground to the sky.
Dutch