OP Rootstocks?

[Tim DH]

Hi There

I’ve been saving my own tomato seed for years, (including growing out F1s) but following a plummet in productivity I started experimenting with grafting onto rootstocks.

I’m pleased with the results of grafting, however its rather irritating to have to buy in F1 rootstock seed. Has anyone bred out rootstock F1s?

I grew my favourite F1 rootstock to flowering this year. It looks a lot like a S. habrochaites. I bagged one truss which set no seed. I left another truss alone and have harvested some seed. The flowers are somewhat excised, so I guess these seeds are crosses with my toms and that the mother is self sterile.

I don’t know which of the resistances in the F1 I need! What I’d like to achieve is a self fertile rootstock which works in my soil.

This has quickly got more complicated than I imagined!  Any tips/clues greatly appreciated!!

Tim DH

[Nicollas]

I think you can make your own F1 rootstock by crossing a tomato with a wild relative.

For example :

We therefore tested the interspecific hybrid F 1 L . esculentum cv VF36 x L . pennellii LA0716 as a potential graft rootstock .   This genotype has several advantages for grafting applications .   First, the hybrid is amazingly vigorous in its vegetative growth, as anyone who has had the misfortune to include it in a field trial can attest (a single plant will quickly overwhelm rows on either side) .   Secondly, the L . pennellii parent contributes dominant resistances to multiple races of Fusarium wilt .   As a result, roots of the hybrid are either resistant to or can ‘outgrow’ our common soil - borne diseases, and plants can be maintained indefinitely in pot culture .   Thirdly, the hybrid has wide graft compatibility, not only with the Solanum spp . in question, but also with more distantly related Solanaceous crops, such as eggplant ( S . melongena ) and pepper ( Capsicum spp . ) .   Finally, L . pennellii and its hybrid with tomato are daylength insensitive, and flower continuously throughout the year, with relatively few leaves between successive inflorescences (sympodial index = 2 in L . pennellii ) .   Although the hybrid has an annoying tendency to sprout adventitious shoots, these are easily distinguished from scion branches and pruned off .

https://tgc.ifas.ufl.edu/vol53/volume53/VOL5_14.htm

or https://www.jstage.jst.go.jp/article/hortj/advpub/0/advpub_UTD-199/_pdf/-char/ja

[William S.]

https://jandlgardens.com/xencart/index.php?main_page=product_info&cPath=78&products_id=382&zenid=uc6fklpbf1j8n0vbtili1vgh37

It seems to me like that is what the fellow who runs J and L gardens in New Mexico has done here: bred his own rootstock and he sells it. Just a habrochaites x domestic F1 rootstock. He also sells habrochaites seed.

[Nicollas]

i'm not sure about the protection from late blight that he claims

[William S.]

 I wonder if using a late blight resistant tomato like Iron Lady F1 as the mother of the cross with habrochaites would help. Some accessions of habrochaites might confer late blight resistance better than others?

The F1s can be really vigorous on interspecies hybrids.

[Tim DH]

I think I’m with Nicollas on this one. … A number of rootstock seed suppliers claim blight resistance. … BUT blight is largely a leaf borne disease, so I can’t see that having your scion on a resistant rootstock is going to make any difference.

[William S.]

Potatoes are a underground plant part and they rot from it. Maybe some resistance helps or maybe it's just the extra vigour helps a tiny bit. Or maybe you are right and it is just false hope they are peddling when really we should focus on late blight resistant eating tomatoes.

[Tim DH]

   My greenhouse survived last night’s storm. … And the Norwegian Toms (Imur Prior Beta) still look quite happy. I doubt if they’ll have much sweetness as day length here has just dropped below eight hours. The Norwegian is one of the few toms which survived a late serious frost event unscathed. (April 21st) It’s also fairly resistant to leaf diseases. (It forms leaf scars where the leaf joins the main stem.)

   There is a chance that this could be the father of some of the ?Habrochaites seeds, in my unplanned venture into tomato breeding!

   The ?Habrochaites rootstock cuttings also look quite happy, except for where they are actually touching the snow covered glass!

   Either way, if anyone is looking for some ‘tough’ genes I can recommend IPB. … It’s weakness seems to be soil borne problems.

Tim DH

[Tim DH]

Started some of my (presumed) HabrochaitesxDomestic seed yesterday. Half of it treated in 30mins of 50%Bleach. (A trick picked up on this forum.) I'll do successional sowing on Day4 and Day8 in the hope of having something to work with when it comes to Grafting Day.

The original rootstock (Fortamino) is described as F1, but I don't know if that was itself HabxDom, or HabxHab, or even Habx Something Else!!

TimDH

[Andrew Barney]

The F3 S. Pennellii hybrids are beasts and are actually used as rootstock. I got my F1 seed from TGRC few years back.

I'm not good at grafting but would like to learn. Wondering if double grafted on S. peruvianum would increase ability to cross with domestic tomatoes.

[Tim DH]

As an aside, … I’m not sure what F1 means anyway in plants that are not self fertile!

How can you generate the ‘pure’ lines required to create the F0 parents? As soon as anything gets close to being ‘pure’ it will presumably be self-sterile.

SO: Is my F1 rootstock seed really an F1.. OR is that just a marketing ploy? ... A coded message saying ‘Don’t save seed from this, it will be useless, buy fresh seed from us.’

To be honest, if this (presumed) Habrochaites seed is hard to get to germinate consistently, then there may be a significant advantage in buying fresh ‘primed’ seed, but not because it is labelled F1!

Tim DH

[William S.]

The purchased rootstock tomato F1's are probably pretty uniform as they would get a lot of uniformity from the domestic side. Also on the Solanum habrochaites side, the species has populations known for obligate out crossing, faciltative out crossing, mixed, and selfing. The different breeding methods were / are adaptive in different parts of the species range. So it is even possible that depending on the habrochaites parent selected that the F1 could be a perfectly uniform one. The main feature though is probably exceptional vigour which isn't present to the same extent in the subsequent generations. I would expect your F1 therefore to be real.

Seed might be primed or not. I notice that fresh habrochaites seed I grow myself germinates better probably because it is only a year old and has never been frozen. I've been bleaching mine per the TGRC protocols but Joseph and Andrew have experimented with not bleaching and reported favorable selection. I think bleaching is most warrented for older seed and seed not from your own garden that could harbor disease. Some strains I have a lot of seed from others very little so quantity of seed involved might also inform decisions as to how careful to be when sowing.

The penellii hybrids are similar but an important purpose they have is their graft compatibility with hard to grow wild species.

[Tim DH]

My root stock experiment has just suffered a sudden change of in balance!

The intention was to graft most of the scions onto a commercial stock(Fortamino) and have a few grafted onto seed raised from last year’s rootstock cuttings. ?HabrochaitesXDomestic

My greenhouse takes 18 plants therefore I was aiming at 12 commercial and 6 experimental. SO I planted 15 Fort seed. Being unsure about how the ?Hab would germinate I planted 12 pots, three seeds to a pot. The planting of those three seeds was staggered in the hope of getting at least some useable stem thicknesses on Grafting Day. (I always stagger the planting of my scion seed for the same reason.)

I only had two Fort seed germinate properly (and one miserable runt!) I suspect this is a problem with (commercially) primed seed? They are set up to germinate uniformly in the first season, probably at the expense of being able to germinate in subsequent years! Given the price of rootstock seed in the first place, those two plants I did get are VERY expensive! At least I know that, by striking the tops when grafting, I have a chance of getting two or three plants from each seed.

By contrast the ?Hab seed germinated at 44%. Not all of them (because of the staggering) were thick stemmed enough on Grafting Day, but they should be good enough by Day2.

My best hope now is for 6 commercial and 12 experimental.

Attached, a photo of the scions. A 32 cell ‘Root-trainer’ 3 seeds per cell, 12 cultivars. (First cutting already taken.) Also the healing chamber 42 hours after grafting. About half the pots are grafts and the others are mostly rootstock tops, struck as cuttings. The white clips are on cuttings, to try and get an upright stem to work on later! (One on the left has already straightened itself out.) The clear/sprung clips are on grafts.

Apart from being expensive, commercial rootstock seed tends to be sold in larger quantities. I was quite happy to buy 50 seed, expecting to be able to play with it for at least four years. If the blessed stuff is only good for one year, that's another compelling reason to want to home produce the seed!

Here's hoping!!

Tim DH

[Andrew Barney]

Do you need seed for F3 pennellii hybrids?

[William S.]

It makes sense that dormancy would be reacquired. That is what seed does in the wild. A plant might produce 10,000 seeds but only 2000 or so might germinate in any given year. Then if a good reproductive year only hits every five years on average the population stays stable.