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Post by jocelyn on May 1, 2018 7:52:04 GMT -5
In open pollinated tomatoes, where the seed parent is known, can you tell the pollen parent by whether or not the seedlings are indetirminant or bush type? I have seeds from Defiant, bush type, one seedling is definately crawling/indeterminant, and the only other tomatoes around are more defiant and one cherokee purple. Cherokee purple crawls, and I'm hoping it might be the poppa of one of the seedlings. Does that sound likely?
Let me see, I think folks said earlier that Defiant has one copy each of pH2 and pH3, so the crawling seedling has about 75% odds of at least one resistance gene? I don't remember reading about resistance in cherokee purple?? Does it have any? Last year was a low blight year here, and the first year I grew Cherokee purple.
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Post by Joseph Lofthouse on May 1, 2018 9:48:46 GMT -5
Determinate is recessive to indeterminate. Congratulations, your seedling looks like a hybrid! So that part of the project is more or less straight forward. At my place, I don't think much about things that I can't see. It's hard to measure if a plant is resistant to diseases. How do I know if it is resistant? Or if it just didn't get infected? Disease resistance is more like a QTL trait. There are lots and lots of genes involved that each provide a little bit of resistance. PH2 and PH3 alleles are described as "incompletely dominant" www.apsnet.org/publications/mpmi/1998/April/Pages/11_4_259.aspxwww.ncbi.nlm.nih.gov/pmc/articles/PMC4035550/Currently, more than 60 Solanum resistance genes against P. infestans (Rpi genes), mainly in potato, have been located in 16 regions on 10 chromosomes.
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Post by jocelyn on May 1, 2018 10:35:13 GMT -5
Ah, OK. I think I saw in a table somewhere that PH2 and PH3 are dominant, or dominant with a dosage effect.
The discussion on this board a while back listed Defiant as having one copy of each of PH2 and PH3, so the crawling seedling might have a copy too. After that, I got a bit lost.
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Post by jocelyn on May 1, 2018 11:14:46 GMT -5
Thankyou, those links are great. It explains why you guys are breeding from tomatoes I have never heard of too, grin.
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