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Old October 29, 2016   #32
StrongPlant
Tomatovillian™
 
Join Date: Jun 2016
Location: Europe/Serbia-Belgrade
Posts: 151
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Quote:
Originally Posted by FredB View Post
I've tried several of these crosses over the last decade or so, and I can summarize my experiences.

Solanum pimpinellifolium. The domestic tomato probably originated from S. pim. or a close relative, and this cross is very easy. The F1 between S. lycopersicum and S. pim. is sweeter than either parent, and many of the supersweet cherry tomatoes probably have S. pim. in their ancestry.

S. galapagense. This is a relative of S. pim. with tiny yellow fruit. It is also easy to cross with S. lycopersicum. The F1 is sweet but has a bad off-taste that it gets from its S. gal. parent. You can find F2 and F3 plants that are still sweet but lack the off-taste, but I haven't fully succeeding in stabilizing a line.

S. cheesmaniae. Another yellow one from the Galapagos Islands. Easy to cross, but in my experience the F1 lacks the sweet taste you get with S. pim. or S. gal.

S. habrochaites. This is from another sub-group of the tomato family, and it is difficult to cross with S. lycopersicum. I have had one successful cross out of about 30 tries. The rootstocks bred by Syngenta all seem to be S. habro. If you let a rootstock plant grow instead of using it as a rootstock, you get a huge vine with fuzzy leaves and a distinctive smell. The plants are completely resistant to Septoria and some varieties are also resistant to early blight, as well as being resistant to just about every known root and stem disease. The fruits are about 3/4" and stay hard and green. Oddly enough, crossing green-fruited habrochaites with pink-fruited Brandywine resulted in orange fruit, an interesting example of what geneticists called epistasis (when you get a particular trait with a combination of two genes but not with either one separately). Apparently habrochaites is missing one of the genes on the pathway to orange pigment, and Brandywine is missing a different gene, but when you cross them the F1 has all the necessary genes and can make orange pigment.

S. peruvianum. Difficult. I had one apparently successful hybridization, but the F1 plants all seemed to be sterile as both male and female parents. One of the genes for blue fruit comes from peruvianum, so it must be possible to do this cross, but so far it is beyond my skill.

Fred
Interesting,have you tried crosses between the wild species themselves?
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