Wanted to post about what I've realized about the Hi-Beta breeding I've been attempting.
The tomato I'm trying to achieve is a high beta-carotene, indeterminate paste tomato.
At this time, I'm going to ignore the "paste" part and concentrate on achieving a high-beta indeterminate tomato.
However the gene for high-beta (B) is located on the same chromosome as the gene for indeterminate/determinate (which is noted as sp (self-pruning) so indeterminate is (sp+). The linkage is close enough that I've now realized that it is unlikely to break for the numbers of plants I can deal with (20+ with up to 45 or so if I grow no other tomatoes). So I have realized for breeding purposes I have to effectively treat the beta gene and it originating growth type as a unit.
There is a third gene I want for this tomato - designated as m
og. This is a modifer gene that increases the beta carotene from 50-60% to near 90% only in the presence of the high beta gene. the one I want is the recessive form (I'm going to use just (m) as the designator for this gene in the further parts of this post.
So the tomato I want to ultimately acheive is sp+sp+BBmm
Again the genes are
sp+ - indeterminate
B - high-beta carotene (50-60% when alone)
m - in the presence of B increases beta-carotene to ~90%.
The main 4 tomatoes I've worked with thus far:
97L97 - A high beta-carotene breeding tomato genetics (spspBBmm) (it's determinate)
Jaune Flammee - high-beta french tomato without the modifier gene: (sp+sp+BBMM)
Opalka and
Shannon - for this purpose they have similar genetics: (sp+sp+bbMM)
All these tomatoes have the R (red) gene which I'm going to ignore for the moment, but I wanted to note that B does not 'work' in the presence of the other form of yellow/orange tomatoes that are caused by the recessive (r) gene.
The one advantage I have is the coloring of the tomatoes shows me the beta/modfier genetics:
bb-- (modifier gene doesn't matter the fruit will be red )
Red.png
B-M- (high Beta without modifier gene with be orange-red (orange, then developing an red blush (although the blush can be slow to appear)
OrangeRed.png
B-mm (High Beta with modifier gene will be orange and never develop a red blush)
Orange.png
So a cross between 97L97 and Opalka yields an F1 Hybrid of sp+spBbMm
OrangeRed.png
and a cross with Jaune Flammee and Shannon yielded an F1 Hybrid of sp+sp+BbMM which is also
OrangeRed.png
I thought of crossing the two hybrids but the results were disappointing. Also in looking at the Punnet square that instead of the 8X8 square you'd think of with 3 separate genes it is much smaller because you're handling the sp gene and the beta gene as a locked unit:
Hybridcross.png
So I considered taking either of my original F1s and BC to the other Beta
(97L97 X Opalka) X Jaune Flamme
HybridOp97BCJF.png
The F2 generation look like this (depending on whether the seed you got is MM or Mm
BC97xOpBCJFF1Breedout.png
I actually like the BC of the 97L97 back to the Jaune Flammee X Shannon slightly better:
HybridJFShBC97.png
And the resulting F2s:
BCJFXShBC97F1Breedout.png
So I'm going to do that and I'm also going to cross Jaune Flammee and 97L97:
The F1:
JFx97F1.png
And the resulting F2:
JFx97F2.png
And all this is long before I get to breeding toward a paste!!!!