Breeding for Late Blight Resistant Tomatoes

[Diane Whitehead]

only one packet?  Johnny's will pay the postage if you buy $200 worth.

[William S.]

only one packet?  Johnny's will pay the postage if you buy $200 worth.

I only ever want about one packet of anything!

Except for that one time from Joseph!

[William S.]

It's a little cheaper from Territorial for ten seeds but the shipping makes it $13.10 usd. Wonder if I can find it on a seed rack anywhere.

[William S.]

Found this AAS winner called purple zebra f1. It has ph2 and ph3 but no idea if homozygous. Still potentially useful when trying to isolate a trait like striping. Grown as a dehybridization some segregates would almost certainly become homozygous for both in an area with heavy late blight pressure and the striping should be stable as it seems to be recessive at least in my limited experience.

Also found on the territorial website Buffalosun F1 a bicolor and a few other new hybrids including Darkstar which list LB but not if they are PH2 PH3 homozygous. They are also out of stock on smaller packet sizes. Still more colors of tomato with some late blight resistance increases the variety of late blight resistant tomatoes a late blight afflicted grower/breeder might have to work with.

With a collection of say Darkstar F1, Buffalosun F1, Galahad F1, Purple Zebra F1, Lizzano F1, and Iron Lady F1 you would certainly have the beginnings of a nice colorful and variable late blight resistant grex.

It might be worth crossing hybrids with homozygous PH2 and PH3 like Iron Lady F1 to open pollinated varieties with some late blight resistance to get higher levels of resistance faster. Would be especially true for someone working in an area currently prone to late blight or if the worst-case scenario Carol predicted came to pass and the spore producing strains became endemic everywhere in the U.S. Which would turn my area into being oh say a once in 20-year Late blight problem to a every year late blight problem as soon as it got here.

In terms of days to maturity which is an important consideration for me these are all over the place Lizzano F1, Galahad F1, and Purple Zebra F1 are all reasonable as transplants here.

[Roland]

The wet year in 2021 show the recistance of Buffalosun F1 is not based on ph2 and ph3. It was very susceptible for phytophthora.

Purple zebra F1 is heterozygous for both ph2 and ph3. Hope someone can ship seeds for 2022 to Netherlands?

[William S.]

Speaking of different sources of LB resistance ph4 is available but seldom mentioned. I recently obtained a ph4 accession though I'm not sure what the utility is? Then ph5 is supposed to be good and Carol said she expected Oregon State to release it shortly a few years ago and we seem to still be waiting.

Buffalo Sun F1 seems about the same as Skykomish as far as utility for late blight breeding. Very long season bicolors with partial resistance.

In the Netherlands do you have the spores that overwinter Roland?

Would it work there to grow the heterozygous purple zebra f1?

Does EFN ship there?

I've been wondering if it might be possible to put together an interesting segregating grex of crosses with LB resistant varieties and offer it through EFN.

[Garrett Schantz]

Purple Zebra F1 is sold by A.P. Whaley as well.

Some other Frogsleap Farm tomato varieties are sold there as well.

Appears to ship internationally.

[Tim DH]

A new ''Late Blight Resistant'' variety, showing up in England for the first time, but loads of sellers carrying it, is Primabella. I didn't stumble upon it last time I searched. About 6 months ago. ... So I'm guessing some mega seed supplier has done a massive grow-out.

It's open pollinated. One website mentions sister varieties from a German breeding program.

Tim DH

[Nicollas]

Its from Culinaris : https://culinaris-saatgut.de/?s=Toleranz

[Nicollas]

Does EFN ship there?

I've been wondering if it might be possible to put together an interesting segregating grex of crosses with LB resistant varieties and offer it through EFN.

Yes EFN ships to Europe. That would be a very good use of EFN to spread seeds to other places.

[Roland]

Speaking of different sources of LB resistance ph4 is available but seldom mentioned. I recently obtained a ph4 accession though I'm not sure what the utility is? Then ph5 is supposed to be good and Carol said she expected Oregon State to release it shortly a few years ago and we seem to still be waiting.

Buffalo Sun F1 seems about the same as Skykomish as far as utility for late blight breeding. Very long season bicolors with partial resistance.

In the Netherlands do you have the spores that overwinter Roland?

Would it work there to grow the heterozygous purple zebra f1?

Does EFN ship there?

I've been wondering if it might be possible to put together an interesting segregating grex of crosses with LB resistant varieties and offer it through EFN.

Its not clear for me if we have spores that overwinter. Most people say the phytophthora start in potatoes and later it get to tomatoes.

In Netherlands is working:
Homozygous ph2 is not working
Heterozygous ph3 is giving a bit resistance but not enough
Homozygous ph3 is working very well
Heterozygous ph2 and ph3 is working very well
Homozygous ph2 and ph3 are best but there is still some infection.

Hence Purple zebra F1 heterozygous for ph2 and ph3 have very good potential for Netherlands.

ps Skykomish seems to be homozygous for ph2 and do not show resistance in Netherlands.
The cross of Skykomish x Primabella  is working very well because this cross is heterozygous for ph2 and ph3.

[Roland]

A new ''Late Blight Resistant'' variety, showing up in England for the first time, but loads of sellers carrying it, is Primabella. I didn't stumble upon it last time I searched. About 6 months ago. ... So I'm guessing some mega seed supplier has done a massive grow-out.

It's open pollinated. One website mentions sister varieties from a German breeding program.

Tim DH

I grow Primabella for serveral years. Resistance is very good.
Primabella is a inbredline of Philovita F1. Philovita F1 is heterozygous for ph3. Hence Primabella seems to be homozygous for ph3.

[Tim DH]

Hi Roland,
   Thanks. ... That is useful/helpful information.

Tim DH

[Tim DH]

Hi Roland,
   You state that 'Homozygous ph2 and ph3' are best. ... Can you name any varieties?
   I assume your interest in Zebra F1 is because growing it out should produce some 'Homozygous ph2 and ph3'?
   Are you also growing out 'Skykomish x Primabella' with the same aim??

Tim DH

[William S.]

I'm still not convinced that anything available here in the U.S. but Iron Lady is homozygous PH2 and PH3. Sounds like Galahad is homozygous PH3.