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Old March 31, 2011   #14
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carolyn137's Avatar
Join Date: Jan 2006
Location: Upstate NY, zone 4b/5a
Posts: 21,175

had it explained over lunch. He developed a quick, comparatively cheap genetic test for resistances. (Lower case indicates lack of the function. Mi: root knot nematode resistance, mi: doesnt have teh resistane.) Some varieties are known to have resistances(BHN-444) and some don't (Riesentraube) and those were used to determine which nucleotides could be used as markers. pages 21-25 show results of this testing.

The developer of this method will use it to make heirloom-quality hybrids that are resistant. This is good- that means that if we have a spot of garden with fusarium, we can grow such varieties there. (I think one can use grafted heirlooms, too.) Another possible benefit is if this is picked up by growers- then perhaps we can have more "real" tomatoes in super markets.

Anyways, it is a cool bit of biotech. I am sure that there are quick disease tests that have been developed, but they are likely proprietary and held by major plant breeding companies.

The diseases that matter to me are typically foliar, like blight, so resistance to these doesn't affect me either way.


What's important is not jsut Iding the nucletides involved with Septoria, b'c with the other ones you mentionmed the genes are already known and used, but actually isolating any genes found for Septoria tolerance.

And even that isn't enough if we use the example of Early Blight b'c while genes are known for that thyey're low level so aren't much help.

There are several groups I know of who are working on finding the actual gene(s) involved with Septoria to be able to use it (them) if it ( they) turn out to be high level and useful.

But about the Fusarium you referred to, yes, growing F tolerant plants is OK as long as one knows which races are present in the area where they grow b'c there's no cross tolerance, but again, whether it's with grafted plants or with F1 hybrids that have the relevant genes it only means a week or two more of plant life, which as a few mentioned above, including me, are of use only for large scale commercial farmers.

heck, if all varieties were tolerant to everything out there we wouldn't have so much fun trying to ID tomato diseases at message sites such as this one.

Some will say that this or that OP variety is tolerant to this or that pathogen but that really depends on the presence of the pathogen in any given season and the level of that pathogen in the environment.

All F1 hybrids that have alphabet letters next to their names have to be challenge tested in an approved lab with the relevant pathogens under controlled conditions, with controls, before they can be so approved to list those tolerances.
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