Parsnip progress

A while since I posted - gardening takes time.
Finally the seeds on my Short Fat Parsnip parents are ready. The Halblange and De Gurnesey have set seed synchronously, but the Kral, and the late-planted Melbourne Whiteskin have been tardy. This has implications for parsnip breeding, since the trigger for flowering is presumably day length - manipulating these varieties so that they flower together will take a bit more thought than say for corn, where you can stagger planting times. Don't think that will work for a biennial. But I think there has been sufficient overlap in flowering to allow some cross pollination.

But this difference in flowering times has further implications. Accepted advice when seed collecting is to harvest the best seed. In the case of parsnips, it looks like the first umbels have the best seed. And recall that parsnips need a big gene pool for a healthy breeding population. So in a perfect world I would collect the seed from the first umbels of all four varieties I'm growing.  But the first umbels on the early flowerers won't have crossed with the later varieties. So I've seperately bagged the seeds from what I hope are contemporaneous seed heads - the earliest from the Kral and Melbourne Whiteskin, and the second pick from HLW and DG which started flowering earlier.

On another note, the second sowing of Kral which took place in early Spring has survived the record dry, but a number of plants have started to send up flower spikes. This presents me with a dilemma - do I havest this seed (which might develop too late in the season anyway) or do I reject this seed, since it comes from individuals that are prone to annualism rather than biennialism? I don't wish to encourage genetics that allow the parsnips to bolt in one season - I might end up with a population of bolters, giving lots of early seed, but no parsnips to eat!

Below, a picture of the DG (left) and HLW (right) parsnips I pulled after harvesting the seeds.
The HLW has tubbier tubers, so closer to my desired target.

First parsnip seed

My parsips are finally seeding, the heads drying down, and yesterday I harvested the first seeds.
The 4 varieties in the first sowing haven't all flowered or seeded together, though. Halblange Weiss and de Guernsey flowering earlier than the Kral - of which I have only half a dozen plants surviving. My late sowing of Melbourne Whiteskin, which replaced a failed Kral sowing from a different seed source, is also late in setting seed.

This difference in flowering times is a bit problematic - the early seeds from the Halblange and de Guernsey will most likely have only crossed with each other, and my plan was to get a cross with the fat-rooted Kral. The seeds from the Kral are likely to have crossed with the later flowers of the other three varieties, but half a dozen plants makes for a narrow genetic base.

My plan is to harvest the late seed from the Halblange and de Guernsey, and the earliest seed from the Kral, hoping these will have crossed up, and collecting the seed from each variety separately.

It's been the driest spring/summer on record for Bendigo, and it 's been a real struggle to keep anything alive, but the breeding stock has got most of the attention, with my tomatoes now only sad dry sticks.

So just as I want some dry weather to ripen seed, it decides to rain! Gotta love nature...

Male sterility in carrots - some photos

I've got a few pictures of carrot flowers showing the differences between normal and male sterile flower heads.





This is the flowering carrot patch.







 Here's a normal flower head or umbel. The emergent male stamens can be seen like a 'fuzz' over the top of the umbel.





 
 






This plant with coloured flowers doesn't appear to have any stamens.





This plant with coloured flowers has coloured stamens.

 
















One problem with spotting CMS is the development stage of the flowers needs to be right to be able to see the stamens. In addition, production of pollen isn't really obvious.In tomatoes for example, pollen production is pretty easy to see, but in carrots, even in plants that I know are male fertile I can't really see pollen at all.

Here's hoping CMS, in my carrots at least, is indicated by the absence of stamens.

Some Carrot (and other crop) Breeding Concerns

Carrots need to have a wide gene pool in the population or after a number of generations, inbreeding depression may occur resulting in poor, unproductive plants.  So it’s not a good idea to collect seed from only one or two plants - just like I have done with my self-seeded Baby carrots. So how many should you use? Best advice is a couple of hundred plants, but a minimum of around 50 is about as low as you should go.

I need to make a slight diversion. Hybrids, crosses between different varieties of the same vegetable, are known to be desirable. They often have better vigour than either parent, so modern agriculture has really focussed on the development of hybrid varieties. For inbreeders like tomatoes, this isn’t too hard- remove the pollen bearing bits from a flower before it has properly opened, get some pollen from another variety, transfer it to the first plant, and wait for fruits and seeds to develop. Each fruit produces numerous seeds, and each of these child plants will produce lots of fruit for market. So it’s commercially viable to produce F1 hybrid tomatoes year after year by crossing the original parents each year to produce new F1 seed.

But some vegetables, like carrots and parsnips are problematic. You need to have a big population of plants to collect seed from, the individual flowers are tiny, and they are bunched together in big bundles called umbels (thus the scientific name for this family of plants, the Umbellifereae.) So ensuring that the plant doesn’t pollinate itself is next to impossible. You could isolate individual flowers in the flowerhead, remove the pollen, and transfer pollen from another variety, but that would only give you one seed for each crossed flower, producing only one hybrid carrot for market – not a viable concern, really, and not enough to plant out a whole field of carrots or parsnips.

So how come some seed sellers advertise F1 hybrid carrots and parsnips? How do they ensure that every seed is the cross between two parent varieties?

It just so happens that there is a mutant form of some vegetables that don’t produce pollen. All the rest of the flower apparatus is in working order, they just don’t produce pollen. This is known as cytoplasmic male sterility ( I'll do a full post on this later). If this form is one of the parents, then the seed collected from these must have been pollinated by another plant. So grow one row of pollen free parsnips next to a row of a pollen producing variety, and only collect seed from the pollen free ones. Easy! But because of the nature of cytoplasmic male sterility, none of the F1 children will be able to produce pollen – this is not a self sustaining population. Unless there is some pollen producing plants around, the crop will die out.

So this is not a desirable characteristic to introduce into a breeding population if you want to develop a new variety to share.

Unfortunately two of the coloured carrot varieties I was planning on to supply coloured genes for my project are hybrids – so I can’t incorporate them into my breeding mix. But I do have a couple of dozen white, a few yellow yellow, and a couple of  purple carrots to provide some color diversity - hope they work!

Coloured Carrot Project progress

Compared to my successes with coloured snow peas, progress on my root vegetables has been slow – that’s what happens when you start on biennial vegetable breeding.

I planted carrots a number of carrot varieties in the middle of summer last year – Harlequin F1 multicoloured, Purple Haze F1 (a purple skinned orange cored carrot),Lobbericher heritage yellow, Belgian White, French Round, Chantennay, the last of some old Three  Colours Purple that was lying around in the seed shoe box, and a scatter of Baby carrots, that have successfully self seeded for a number of generations, but from a relatively narrow gene pool, since I’ve had 2 or 3 go to seed for the last couple of years.

But some problems arose. First, the French Round didn’t emerge, and I unsuccessfully tried a few other small round carrots until I got a variety to germinate. The delay means they are now out of synch with the coloured varieties, and I don’t think I will be able to get a cross happening.

A further complication with the timing has to do with the approach I used, what Susan Ashworth in ‘Seed to Seed’ refers to as ‘autumn winter spring’ seed production. Some further explanation. A normal biennial root crop would go through the following sequence. Seed sown (or fallen on the ground) would germinate in spring, with damp soils, and warming temperatures. The plant grows over spring and summer, and as the seasons progress, develops a swollen root. Come autumn as temperatures drop the tops stop growing, and the plant hunkers down for the winter, with plenty of energy stored safely away in the root to fuel early growth next spring. When the next spring arrives, the plant switches to reproductive mode, growth restarts, but instead of putting energy into a storage root, it draws on that stored energy to develop flowers. These get pollinated in summer, develop seeds, which dry off over autumn, and are shed on the ground ready to start the cycle over again.

A gardener wanting vegetable seeds of the best quality would dig up the roots in winter, inspect for desirable characteristics and select the best roots for replanting (and eat the rejects). In early spring, replant the good ones, and let them cross pollinate to produce seed.

But what if I just wanted to cross some existing varieties and haven’t got 2 years? This 18 month cycle can be shortened by sowing in late summer, getting good growth to develop, leave the roots in the ground, and letting the plants flower normally in spring. I’m not doing any selection, just wanting to cross varieties at this stage, so I don’t need to inspect the roots.

But when I want to see the results of my cross, I’ll need to revert to the 2 year cycle.

A further complication is cytoplasmic male sterility. Time for another post.

More onions

A few pics of my topset onion inflorescences.

Here's the normal case for my topsets - a little bunch of onion bulbils

Normal bulbils on topsets

But this year - and a bit over the last few years - I've spotted some flowers on my topsets. Info on inducing flowering in garlic, that can be encouraged to set flowers if properly manipulated can be found here.

No reason not to try it on my topsets. so this spring I've been de-bulbil-ing the inflorescences on my topsets. The close proximity of a few rows of flowering bunching onions might allow a bit of cross pollination, so who knows what might result.

Honeybee on the bunching onion flowers

There are lots of pollinators around, and there seems to be a few flowers on the topsets that have set seed. A few weeks will tell if I (and the bees) have been successful.

What looks like pollinated flowers on my topset onions

A new onion project

Onions (Allium cepa)come in all sorts. Bulbs, big and small, long lasting and eat now, raw and cooking. For the purposes of growing onions, bulbing onions are divided into groups depending on the trigger they need to start forming bulbs - short day, medium day and long day are the usual designations. Growers in the tropics have problems growing the long keeping varieties, most of which need long days to trigger bulbs. (Actually onions respond to the period of darkness, rather than light, but let's ignore that for the moment.) This is all very messy.

I've never had much luck with onions. Timing is everything. Here in Bendigo I can choose to grow any variety I like, summer night and day periods are sufficiently different to allow me to grow short, medium and long day varieties. But I never get the sowing time right, the seedlings sit and sulk through early spring, they get swamped by weeds when young, and last year, my alliums (garlic and leeks) were struck with a failure to thrive disease, that I'm yet to diagnose.

But there is another candidate on the patch - topset or multiplying onions. These hardy individuals grow in bunches, and instead of forming flower heads, they develop little bunches of new onion bulbs at the tips of the stalks. There is some confusion about the exact phylogeny of topsets, some suggesting they are a distinct variety of A.cepa, or perhaps a hybrid between A.cepa and Allium fistulosum, the bunching or welsh onion.


There are as many names as there are cultivars - walking onions, topset onions, multiplying onions, Egyptian onions. (Potato onions are probably in the same group, but don't seem to top set bulbils). Some of these set small basal  bulbs and die down, some set small bulbs and keep growing. They come in red and white and brown. They are not really sold in Australia, and I've only ever seen them once in a nursery. Mine don't set bulbs at all really, just a minor thickening of the base. Every generation is the same, because they are vegetatively propagated.

But the big advantage of these is they grow throughout the year for me. They were totally unaffected by the disease I got, they take no trouble, they're always there in the garden, and they are so easy to propagate. Last year I noticed that some of the topset formations had a few flowers scattered through the bulbils. I did nothing. But in the last 12 months I've been reading up on alliums. Garlic also doesn't set seed. But some researchers have been inducing flowering in topset garlic (which produces little bulbils on top of the stem, just like topset onions) by removing the bulbils as soon as they form. This fools the plant into thinking it needs to reproduce, and since the bulbils aren't working, maybe they should indeed produce some fertile flowers. I wondered if this would work with my topset onions. I've spent several hours over the last week picking bulbils out of my topsets. And the flowers look like they are fertile. Good news.

A further problem with some plants that are reluctant to produce flowers can be the inability to produce viable pollen, or self incompatibility issues - where the pollen from the same plant can't pollinate its own flowers. Since all my topsets, despite being in lots of distinct clumps are all the same plant genetically, there might be incompatibility issues. By chance, I'm also growing some Japanese bunching onions, A. fistulosum, which is flowering profusely. Bees are all over the big round flower heads, and with luck, I might get a bit cross pollination, if the topsets are self incompatible (which I don't know) Seems like a bit of lucky insurance.
So what might I get out of these if they set seed?

Who knows! Maybe I'll get bigger more robust plants. Apparently lots of vegetatively propagated plants build up a virus load, which is transmitted from mother to daughter. By going to seed, its possible to shed this viral load, leading to increased vigour in the offspring. Or maybe some genetic recombination wil occur and some ancient ancestral traits will emerge. Who knows how long these things have gone without reproducing? I've been inspired by the work of Kelly Winterton, who has been quietly developing extraordinary potato onions in his backyard in Utah.

I'm not sure where mine came from. My mum had them in her garden, and passed them on to me, but I think they died out, and I replaced them with some material I bought in Albury when I lived there 15 or so years ago.