Late Blight breeding results
There is one area where I plant tomatoes every year. It is usually the first to come down with late blight and of course, I do not every spray for control. I think the blight is fully entrenched in the soil here and no effort is made to clean up the debris in any year. This plot is just outside Monroe, WA.
It appears that Ph-2 and Ph-3 are still operative in controlling the outbreak.
Make My Day is one that has both the Ph-2 and Ph-3 gene in a homozygous pairing. No blight. It is related to my Skykomish variety which is also tolerant to blight.
Matt's Wild is homozygous for Ph-2. No blight.
The tomato hybrids that have Ph-2 from one parent have slight resistance to the foliage, but not as much control on the fruit as I would like.
Hybrids with Skykomish which is homozygous for Ph-2 and Ph-3 have slight resistance.
I will check the progress as the blight burns through. It started about three days ago.
With many, many hybrids of these lines being put away as F-2 seed, a fuller evaluation for 2011 will be to look for segregations that are true breeding for the best blight resistance/tolerance. Homozygous traits need to be found in every time of tomato, whether is a red, bi-color, green, striped, black, yellow, etc.
I don't know which strain is going through the area but it seems to be similar to the one we had here in 2004 and 2007, whereas Ph-2 was workable. 2008 knocked down hybrids like Mountain Magic which carries from one parent-- the genes Ph-2 and Ph-3. I have F-3 plants of Mountain Magic in other locations and hybrids between selected F-2's of it.
I am awaiting results from Europe about some of my strains, especially from the fella that named the blight blue 13 over there.
My 2009 crop was not evaluated well since I was gone from early Sept through all of October. But I was harvesting tomatoes in November last year.
Tom Wagner
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