OP Rootstocks?

[Tim DH]

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.

   

[Tim DH]

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

[Tim DH]

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

[Andrew Barney]

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!

[Tim DH]

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 4^oC for the next fortnight. Greenhouse soil temp currently 14^oC... 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

[Tim DH]

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!!

[Tim DH]

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.

[Tim DH]

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.

[Tim DH]

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.