Breeding for Late Blight Resistant Tomatoes

[Tim DH]

Hi William,
   Like I mentioned. ... Site not easy to negotiate!  Try this link for colourful Broads

https://kokopelli-semences.fr/fr/p/L0385-Ianto-s-Return

   Tim DH

[William Schlegel]

Ah, I used a packet of Ianto's return from a tiny company in Washington state as a foundation to my strain of favas!

The company I think I got them from no longer sells them they've started a mix! https://www.resilientseeds.com/store/p181/Fava_-_Mixed_%28Certified_Organic%29.html

[Roland]

What do u know about Celano F1?

https://all-americaselections.org/product/tomato-celano/

[Tim DH]

Hi Roland,
    I Can't find any reference to Blight Resistance. Have you heard otherwise?

Tim DH

[Roland]

I got from the breeder that Celano F1 does not have the ph3 gene.

[Tim DH]

I set up a trial, growing reputedly blight resistant varieties right next to potatoes (at two sites 1km apart) and waited for the blight to arrive......

Wouldn't you know it? Blight wasn't a problem this year!

Anyway here are the results:

Stupice: OP Easily the first to produce ripe fruit. (Mid/late July) Acceptable flavour. Beware! As discussed elsewhere on this forum, there are a number of different varieties going under the name Stupice! (Mine came from Realseeds.co.uk)

Resibella: OP The heaviest cropping (2.5kg from one plant). Leaves had a bizarre tendency to sprout shoots all over, (see pic taken early on before they created a forest!) Un remarkable flavour. Won't grow again.

Primabella: OP Fruits from mid August. Acceptable flavour.

Sunviva: OP Low cropping (0.5kg) Fruit from early August. Tendency for splitting. Good Flavour.

Crimson Cherry: F1 Fruit from Late August. Tendency for splitting. Good Flavour. Very poor seed germination. (Which is annoying when you've paid for F1 seed!)

Summerlast: F1 Tasteless fruit. Sickly plants. Only positive point, the fruit looks very nice!

Mountain Magic: F2 (Seed from a fellow forumist) Grew four plants, saved seed from one. Fruit from mid August. Acceptable flavour.

Tim DH

[Roland]

What kind of segregation did u get from Mountain Magic F2?

[Roland]

I got from the breeder that Celano F1 does not have the ph3 gene.

Celano F1 was one of the first plants that got late Blight.
A few days later SkyReacher got also infected.

Sunviva, Galahad and Mountaineer Pride did not get a blight infection.

[William Schlegel]

My MMM x purple zebra F1 cross is still a green fruit. It is in the Greenhouse though so maybe it will make it.

[Nicolas]

New sources of resistance in pimpi PI 270441

Identification of late blight resistance quantitative trait loci inSolanum pimpinellifoliumaccession PI 270441

f the four LB resistance QTLs identified in PI 270441, two(on chromosomes 1 and 10) colocalized with LB resistanceQTLs previously reported in another tomato wild accession(Merk  et  al.,2012)  and  two  (on  chromosomes  1  and  11)appeared to be new

[Tim DH]

Hi Roland,
   Sorry about the slow reply. ... The only segregation I was looking for was Blight Resistance (which didn't get tested) and taste (which did get tested!)
   Apart from that, all the seedlings were indeterminate, all fruits were medium sized reds, more blocky than spherical. Was there any particular trait you were interested in?

Tim DH

[Roland]

Mountain Magic is a Cross between a Cherry with the Rin gene and a Beef with ph2, ph3, determinate.

So i espected a lot of difference in size of the fruit and some plants that where homozygous for the Rin gene and stay orange or green with a very long shelf life?

Also I espect a lot of difference in taste ?

[Tim DH]

Hi Roland,
   That's interesting. ... My small grow out (only four plants) gave NO indication of the parentage you describe!

   I am intending to repeat the grow out next year in the hope (Ha! Ha!) that Blight might show up next time. (I have plenty of the F2 seed.) I was thinking of running a Crimson Cherry F2 trial along side it.

Tim DH

[Adrian]

In france we tried to cross mountain magic with orange jazz.
We want a tasty tomato with ph1 and ph2 with the minimum rin effects
https://www.les-tomos.fr/viewtopic.php?f=111&t=1915

It look important to make the difference between rin and rin g2
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0249575
If she stay green i thinked she has rin and if she stay orange she has rin g2 for me.

[Roland]

Very interesting. How many plant did u grow and did u find segregation in blight resistance? Dit u notice difference in plants with the Rin gene and without the Rin gene?

My Galahad F3 all show very good resistance and are homozygous for the ph2 and ph3 gene. The disadvantage is that they do not set fruit in May and June and therefore ripen late. Still I got hundreds of kilos of tomatoes