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General Category => Nightshades => Plant Breeding => Tomatoes => Topic started by: Tim DH on 2021-11-22, 10:31:26 AM

Title: OP Rootstocks?
Post by: Tim DH on 2021-11-22, 10:31:26 AM
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
Title: Re: OP Rootstocks?
Post by: Nicollas on 2021-11-22, 10:39:20 AM
I think you can make your own F1 rootstock by crossing a tomato with a wild relative.

For example :
Quote
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
Title: Re: OP Rootstocks?
Post by: William S. on 2021-11-22, 11:15:33 AM
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.
Title: Re: OP Rootstocks?
Post by: Nicollas on 2021-11-22, 11:17:24 AM
i'm not sure about the protection from late blight that he claims
Title: Re: OP Rootstocks?
Post by: William S. on 2021-11-22, 01:19:29 PM
 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.
Title: Re: OP Rootstocks?
Post by: Tim DH on 2021-11-24, 07:05:02 AM
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.
Title: Re: OP Rootstocks?
Post by: William S. on 2021-11-24, 08:32:11 AM
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.
Title: Re: OP Rootstocks?
Post by: Tim DH on 2021-11-27, 08:06:46 AM
   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
Title: Re: OP Rootstocks?
Post by: Tim DH on 2022-02-28, 05:04:21 AM
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
Title: Re: OP Rootstocks?
Post by: Andrew Barney on 2022-02-28, 08:37:09 AM
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.
Title: Re: OP Rootstocks?
Post by: Tim DH on 2022-03-02, 05:13:09 AM
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
Title: Re: OP Rootstocks?
Post by: William S. on 2022-03-02, 05:59:19 AM
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.
Title: Re: OP Rootstocks?
Post by: Tim DH on 2022-03-28, 09:21:32 AM
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
Title: Re: OP Rootstocks?
Post by: Andrew Barney on 2022-03-28, 09:28:32 AM
Do you need seed for F3 pennellii hybrids?
Title: Re: OP Rootstocks?
Post by: William S. on 2022-03-28, 12:23:14 PM
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.
Title: Re: OP Rootstocks?
Post by: Tim DH on 2022-03-29, 03:57:30 AM
Hi Andrew,
   Thanks for the suggestion/offer. I think this year’s rootstock experiment already has enough unknowns in it! Adding in pennellii may be interesting at some point in the future. I’ll review how far I’ve got in the Autumn and maybe get back to you.

Hi William,
   That’s an interesting thought.

   My hypothesis was that primed seed had sort of been ‘aged’ to persuade it to germinate ASAP. Since it didn’t get the chance to germinate last season, I presumed the seed, holding itself in a state of readyness, had died. If I’m right then the few that did germinate had just managed to hang on long enough and I’ll get 0% germination next year.

   Your hypothesis that the seed had fallen back into dormancy would mean that I should get a similar low germination rate next year. (The seed is pelleted, which would make any attempt to re-prime it difficult.)

   This year I’m intending to back cross some of the ?Hab onto the Fortamino. Hopefully I’ll get plenty of seed which I can sow generously for a few years. It all hinges really on how effective the ?Hab rootstock is at overcoming my soil borne problems.

   
Title: Re: OP Rootstocks?
Post by: Tim DH on 2022-04-12, 10:11:00 AM
Went to visit the old man today (95 this month!). He doesn't grow much now except Paphs and Daffs. This one Paphiopedilum Maudiae. (Half a century ago he did some of the early work on embryo rescue in Brassica.)

Amongst other things we chatted about my tomato rootstocks and he asked if I’d considered whether the resistances I was interested in might be cytoplasmicly inherited. Of course I hadn’t!

I’ve now had a quick peep down that particular rabbit hole and decided that I’m not particularly interested in the mechanism of inheritance! I just want rootstocks which work!!

ANYWAY  Graft Batch One was two thirds successful. Of the four fails, only one seemed to be actually a graft fail. Three of them looked more like root rot in soggy compost. However ALL of the rootstock cuttings took. That gave me plenty of options for the Graft Batch Two, which is looking like it will have a much higher success rate.

I did ask Dad about my plan to back cross the best F2s onto the F1, and when might self sterility become a problem. He said it depended on the mechanism of the sterility and asked what evidence did I have that the F1 IS  actually sterile!     Always more questions than answers!!!

 Tim DH
Title: Re: OP Rootstocks?
Post by: Tim DH on 2022-04-16, 09:40:54 AM
Graft Batch Two 100% success! ... 100% on the cuttings rooting too.

I now have enough grafts to fill the Greenhouse, however they are not all the combinations which I'd prefer. (Mainly because I only got two seedlings from the commercial rootstock seed.) Batch Two healed in eight days, so I'm thinking of doing a third batch, to see if I can fill some of the combination gaps. The third lot will only be about a week behind the second. (There is a local Market Garden outfit which has expressed an interest in any spares!)

Next I'll have to choose which of the rootstock cuttings to grow on to flowering. (Tho' I might graft some out door toms first.)

Tim DH
Title: Re: OP Rootstocks?
Post by: Andrew Barney on 2022-04-16, 11:43:14 AM
Went to visit the old man today (95 this month!). He doesn't grow much now except Paphs and Daffs. This one Paphiopedilum Maudiae. (Half a century ago he did some of the early work on embryo rescue in Brassica.)

Amongst other things we chatted about my tomato rootstocks and he asked if I’d considered whether the resistances I was interested in might be cytoplasmicly inherited. Of course I hadn’t!

I’ve now had a quick peep down that particular rabbit hole and decided that I’m not particularly interested in the mechanism of inheritance! I just want rootstocks which work!!

ANYWAY  Graft Batch One was two thirds successful. Of the four fails, only one seemed to be actually a graft fail. Three of them looked more like root rot in soggy compost. However ALL of the rootstock cuttings took. That gave me plenty of options for the Graft Batch Two, which is looking like it will have a much higher success rate.

I did ask Dad about my plan to back cross the best F2s onto the F1, and when might self sterility become a problem. He said it depended on the mechanism of the sterility and asked what evidence did I have that the F1 IS  actually sterile!     Always more questions than answers!!!

 Tim DH

Your Dad sounds like quite the knowledgeable person!
Title: Re: OP Rootstocks?
Post by: Tim DH on 2022-04-19, 07:25:47 AM
Hi Andrew,
   It’s fun having Dad around. He’s not always right, but its always worth running an idea past him.


   Today is transplant day for the first batch, out into the greenhouse. Outdoor temperature not supposed to get below 4oC for the next fortnight. Greenhouse soil temp currently 14oC... Pictures below:

Batch One in 10cm pots, ready to go out.

Batch Two in 6cm pots, ready to pot up to 10cms.

Batch Three grafts and cuttings in the propagator.

Spare rootstock cuttings not used in (smaller) Batch Three.

Outdoor seedlings in a 32cell Root-trainer, almost ready for grafting.

Tim DH
Title: Re: OP Rootstocks?
Post by: Tim DH on 2022-04-26, 09:39:56 AM
Well! This little stump (see below) could be a game changer for me!!

This is the rootstock of the graft fail from the first batch. It was decapitated on March 26th.  .. For some reason I never got round to scrapping it, the poor thing just sat on the side. When I got round to doing the third batch (April 16th) I noticed that the stem still looked good, so I re-cut it and grafted on a scion, which took! That’s a full three weeks between de-capitation and grafting.

One of the problems with grafting is if the stem diameter of the rootstock gets thicker than that of the scion. (The other way round is not a problem because you can always take a piece from higher up the scion, where it is thinner.)

Another problem with grafting is if the rootstocks germinate non-uniformly (like my F2s did) because then they get to the right stem diameter at different times.

What this little stump is telling me is that I can start my rootstock seed off early and de-capitate them as they get to the right diameter. The headless rootstocks will just sit there until I’m ready to graft. I would even have time to strike the cuttings and get a second rootstock!

Already, I’m saying  ‘Roll on next year!’ … and I haven’t even picked a tomato yet!!
Title: Re: OP Rootstocks?
Post by: Tim DH on 2022-05-07, 12:44:11 PM
Forty grafts done. That’s eighteen of cultivars for my unheated greenhouse (I finished getting them in today) and six duplicates for the poly-tunnel at the market gardeners. Plus sixteen of supposedly Blight Resistant cultivars to trial in the open garden and allotment.

The success rate with grafting was much better for later batches. Maybe because the days are now considerably longer.

I managed to get four grafted plants from each of the FortaminoF1 seedlings and also retained the mother plants as cuttings. So I stand a chance of getting some back-crossed seed for next year.

Most of the graft unions look nice and neat, tho’ I have some oddities. In the past I’ve not found ugly grafts to be predictive of poor yields, however I will keep a special eye on these fellows. I did consider culling the one below, … BUT … the rootstocks I want are ones that protect my scions from soil born diseases, rather than ones which make nice looking graft unions. … This one may yet be a winner! (The two stems were the same size when I spliced them!)

There is a fair degree of variability in the stem colour and hairiness of the F2 rootstocks. So I guess that indicates that FortaminoF1 is, what one might call, a real F1, with diverse parents.
Title: Re: OP Rootstocks?
Post by: Tim DH on 2022-06-05, 10:19:56 AM
First flowers on my (presumed) HabrochaitesxDomestic rootstock plants seem a bit smaller than the flowers on the (presumed) Habrochaites F1 plants. This one has a well exerted stigma! (It flowered before I got round to bagging it, so I cut it off to be on the safe side.)

My first question is whether any of the plants are self fertile. So they are all going to have their first trusses bagged.
Title: Re: OP Rootstocks?
Post by: Tim DH on 2022-06-20, 09:24:05 AM
Here are five rootstock cuttings growing in my South facing window.
(They were photographed after dark so that they weren’t just silhouettes!)

Centre Left and Centre Right are F1s from the original seed. They are about 1300mm high and I’m about to decapitate them! (I’ll root the tops again.)

I bagged the first trusses on each F1, to see if I can get some selfed seed. They have set some small fruit.
The second trusses, I’ve crossed with each other. My understanding is that if they are true F1s then I’ll get no better seed set from this cross, however initial observations suggest that these fruits are a bit bigger!

The other three plants are (sort of) F2s, except that since I think the F1s are self sterile, these plants are not your usual (selfed) F2s. I don’t know which of my domestic toms provided the pollen.

All three plants are visually less vigorous than the F1s. The centre plant is only 400mm high.

I’m not so worried about the vigour, I’m more concerned about retaining the root resistances of the F1s. That question should be resolved by the grafts which are currently fruiting in the greenhouse. Initial observations suggest that all the F2s have a decent amount of root resistances.

On the assumption that none of the F1/F1 crosses work…. I’ll be back crossing from these F2s.