Piennolo del Vesuvio X LA0417 septoria tolerance
 

I've mentioned this cross several times and finally today had a few ripe fruits. The background for this cross is my search for high septoria tolerance which led me to grow several wild species from TGRC in 2013. I found 3 plants that were exceptional.

LA0417 is S. Pimpinellifolium which is fully cross compatible with domestic tomato. It showed better than average tolerance to septoria and was the best of the S. Pimpinellifolium lines I grew.

I also observed good tolerance in LA2869 which is S. Habrochaites. This line is self incompatible which is typical of S. Habrochaites. The tolerance was good, but not exceptional, there was some leaf damage toward the end of the season.

The best tolerance was LA2175 which is S. Habrochaites and happens to be a self-compatible line. These plants were totally unharmed by septoria and were still fruiting at the end of the season.

I put several plants in 1 gallon pots late last year and attempted crosses. Piennolo del Vesuvio was one of the potted plants. It is a potato leaf variety so was extra easy to tell if crosses took given that the male lines are all regular leaf. This spring, I grew a few seedlings from Piennolo and had 3 regular leaf. I put these into my garden. Two of them are from LA0417 and the 3rd is from a large fruited variety. I had tried some pollen of Black From Tula and Aunt Ruby's German Green so one of those is the probable parent.

Today I picked 2 ripe fruit and there is about a gallon nearly ripe on the LA0417 derived plants. Flavor is good though not quite as sweet as I like. Texture is more like Piennolo, a bit mushy on the inside. Aroma is clean, slightly pungent, good fragrant essence of tomato. As an F1 cross, the results this year do not predict results for F2 plants. I will save a few hundred seed and see what next year brings.

Septoria tolerance of the F1 plants is mid-range, not as good as LA0417, but significantly better than susceptible plants growing in my garden. I expect the tolerance to be based on multiple genes therefore will be slow to concentrate into a stable line.

Why are crosses like this useful? Because the "immune system" of wild species is much more robust than domestic tomato. A few generations of growing and stable large fruited plants can be developed that will bring useful new resistance genes into plants gardeners will enjoy growing.

Interesting project for an interesting tomato.

Good Luck!

Great ideas! Looking forward to seeing how this turns out!

Great project, good to hear you're getting the F1 seeds already.
Hope you find some super resistant F2's.

I'm guessing this is not an F1 that you would cross with something else? And instead, look for those wild spp traits in the F2 first?

It would be best not to cross this F1 with other tomatoes because the number of subsequent plants to grow would become unmanageable. I'm going to try to stabilize the disease tolerance traits into a large fruited tomato first, then work on subsequent crosses.

Thanks for the update Dar. I have fruit set on a couple of crosses to a LA4017 plant from seed you kindly sent me last winter. I'll plan to grow out the F1 this winter and go to the field with F2 progeny next year.

Frogleap, re the seed I sent, I grew several of them out this spring and found about half of them were either pure S. Habrochaites or else a cross of LA0417 X S. Habrochaites. You will be able to tell for sure which it is when the fruit ripen. Pure S. Habrochaites ripen whiteish green, pure S. Pimpinellifolium ripen red, and the cross should be a pinkish colored fruit.

At this point, I'm not sure if I mixed the seed for if the bees were just super busy late last fall.

2014/07/01, I picked a double hand full of ripe tomatoes from this cross. I can pick about a gallon more if I take a bucket to the garden. This will provide way more F2 seed than I can possibly use.

I grew seeds that I'm pretty sure came through you via distribution in 2012 to Tania.
2013 I got a few fruit unblemished fruit -nothing exceptional. My plants seemed to resist disease fairly well, but a curiousity was that these PL plants rolled their leaves at a practically the before the second true leaf appears. Is this normal? I ordered more seeds for a late crop, but nada.
I've got 4 plants going now. They seem characteristically lanky. I've pruned them along the way and the main leader is about head high now. A fair fruit set from mid-May plant-out, but nothing to brag about. Nothing has turned but the green is starting to weaken. The top leaves are now a little less furled now maybe.

Any wisdom you can share on this plant I would appreciate.
I really want to make this variety go if my climate is willing.
Thanks

Any updates to your septoria resistant line(s)? Septoria is something I battle each year, unfortunately.

It sounds from this thread you are probably a number of generations away from having something large fruited with resistance. When that time comes and if you're willing to share, I'd love some seed. I think making crosses with various tomatoes and the resistant strain would make for a very useful, fun project.

How is this year for you regarding septoria?

Any progress you'd be willing to share on this project? The topic is very interesting!

I grew 16 plants in the garden this year of the Piennolo X LA0417 F2. Disease tolerance ranged from decimated plants similar to the Piennolo parent to very low disease incidence on exactly 2 plants. One of the disease tolerant plants had larger and better flavored fruit so I saved seed from it to grow out next year. Unfortunately, I only got a hundred or so seed before a deer got in the garden and decimated the plant. Has anyone else noticed that varmints go for the best flavored first?

Plans for next year include growing at least 24 F3 plants and seeing what segregates out.

Pure LA0417 produces 1/2 inch diameter red fruit on plants with septoria tolerance that I rate 7 on a 1 to 10 scale. Most domestic tomatoes rate 2 or 3 though a few such as Eva Purple Ball rate 5. LA2175 rates 8.5 which is a good bit better than LA0417. None of these are immune to septoria, they are just a lot more tolerant than anything else available.

Analysis given the 1:8 ratio of tolerant F2 plants suggests 3 genes are involved and given the range of tolerance from decimated to somewhat resistant to highly resistant, I speculate that one gene is dominant and two are recessive. One of the recessives has a major effect which has significant implications for further crosses and/or development of F1 lines for fruit production.

I provided a few F3 seed to Randy Gardner and to a few individuals who post on T'ville and are interested in further breeding.

The F3 will not be anywhere close to stable. Fruit from the best plant were about 3/4 inch diameter, slightly pear shaped, with a small nipple similar to Piennolo. I will grow them out at least 3 more generations selecting for best disease tolerance, largest fruit, and best flavor in each generation.

Interesting. I like reading through threads like this. Make me think about the genetics and how you arrive at your conclusions of genes involved. Septoria is the thing I battle most so I look forward to hear how your subsequent years go.

Fusion, would you have any S. pimpinellifolium or S. habrochaltes derived seeds that you'd be able to share for this coming growing season?

I'm down to about 50 seed so can't give out any more F3 at this time, but I have plenty of Piennolo X LA0417 F2 seed. PM me an address and I'll mail you some if you want. The caveat is that you must understand that these will produce small fruit with most smaller than 1 inch diameter and they will have a range of disease tolerance.