Forum area for discussing hybridizing tomatoes in technical terms and information pertinent to trait/variety specific long-term (1+ years) growout projects.
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January 23, 2016 | #46 | |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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Quote:
Some studies of earliness found that the time to first flower, the time from flower to fruit set, and the time from set to ripe, are three distinct traits under separate genetic control (but also subject to influence of the environment). My F1 growouts last year (nine F1's) would lead me to believe that the earliness traits are recessive, with the earliness of F1's similar to the later parent in most cases. I only saw one case of earliness "heterosis" - that was the cross with Stupice. I know these are probably "QTL" s rather than simply recessive, but this is what I found. Last edited by bower; January 23, 2016 at 07:35 AM. |
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January 23, 2016 | #47 |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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Nicollas, thinking about earliness I just looked over the data again and noticed something else: the six F2 plants of Zolotoe Serdtse X Indian Stripe are all within the earliness range of the early parent ZS at 130 days or less, compared to 140 days for Indian Stripe. One is actually earlier and falls in 120 days or less category, which maybe just due to smaller fruit.
The F1 of ZS X IS was like the later parent, by comparison. So there are two crosses that didn't segregate as I expected for earliness: Kimberley X Zolotye Kupola and Zolotoe Serdtse X Indian Stripe. The Stupice X earliness can be blamed on heterosis, since the F1 was itself earlier than the parents and the only F1 I grew with earliness heterosis. So... more questions about the genetics of earliness, raised instead of answered. |
January 23, 2016 | #48 |
Tomatovillian™
Join Date: Sep 2014
Location: France
Posts: 142
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Thanks for explanations. From what i've read, earliness is quantitative and relatively heritable. F1s seems to be close to the earlier parent. But that's not what you've observed
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January 23, 2016 | #49 |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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Well this is for sure, one of the drawbacks of small space.
Unless you grow multiple plants of the parent and the F1, you don't have a comparative value that shows range of variation. When a small number of F2's are grown, you don't have enough data to draw a conclusion. Results could be attributed to chance. Maybe the results are just a measure of "how lucky am I?" All I can say is what is "suggested" by the small amount of data, and would require a further investigation with larger numbers of plants. |
January 23, 2016 | #50 |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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So I went back and reviewed the multi year data for parents and descendants, and I think the earliness results can be explained, for the most part, falling into the pattern which Frogsleap described, that is, in crosses between a smaller and larger fruit, the F2 results are skewed towards smaller and earlier.
It makes sense that a larger fruit would have a longer time to grow and ripen, and since the buds are also larger it makes sense that this could push flowering time later as well. As it happens, the cross between two medium-large fruit IS and ZS (different shaped but not greatly different in weight for me here) seems to follow the same pattern of skewing towards the earlier parent. I happened to get one large fruit in six, but that is chance. The only result that is opposite to the "earliness skew" explanation is the cross between two large fruits - Black Early and Indian Stripe. This is where the skew was the opposite way in my results, only one early out of six. |
January 24, 2016 | #51 |
Tomatovillian™
Join Date: Feb 2013
Location: Czech republic
Posts: 2,534
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Perfect pictures and documents. I always like to read this thread, and I look forward to every sequel.
Vladimír |
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