14 December 2012

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.

12 December 2012

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.

09 December 2012

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


25 November 2012

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.


02 November 2012

Purple podded pea - first F2 line

November 2011 - crossed the first snows and purple poddeds.
Seeds in December 2012. Some sown green on 3rd December - straight out of the mature pod - for a summer shade growout.
One line PP(LSC)XPFM produced about 20 F2 seeds from three greenseed plants harvested on 4 March. These were then sown  - can't remeber if it was green or if I dried them first, but they were planted as seedlings on 25 March.

The original F1 seeds from the first crossed were sown on the 16 February. and planted out on 28 February.

These February sowings were producing fertilised pods in late April, but the early March sowings didn't produce pods until late winter. What a difference a couple of weeks makes.

The later sowings were badly affected by powdery mildew, and by the time they were flowering, many of the plants were so infected that they only produced a few viable pods, some of which were then stripped of their seed by rats or mice.

But I did get one snow pea with colour - a half purple snow. A quick chew on one end of a pod showed it to be sweet and tasty - a bonus. However at seed harvest I only managed to get around 10 seeds. I took the risk, and sowed 3 of them straight away, and have got three F3 plants growing out as tiny seedlings in a tray.
These should be stable for snow pea characteristics - those traits are recessive - but the purpleness is another matter. There is a 2/3 chance the original plant shown above was heterozygous for purple, and 1/3 chance it will be homozygous and stable.

If it was homozygous, I would expect all 3 of the new seedlings to be purple snows - if it is heterozygous, then there is a 3/4 chance that any one of these will be purple.
Oh, the anticipation!




Coloured snow pea progress

An update on the progress in the F2 grow outs.
I did my initial crosses in November 2011, crossing all sorts of peas with others.

The main focus was a search for a purple snow pea - crossing 3 different lines of purple podded peas with 5 different lines of snows and snaps including dwarf varieties and those with supposed powdery mildew resistance.

I also crossed a yellow podded variety with a purple podded, looking for a red podded pea to use as a progenitor for a red snow line. Although the  yellow is supposed to be a snow pea, it has few redeeming features apart from its pale pods, and so seemed unlikely to be able to produce a tasty yellow full snow pea. To get something worthwhile, I figured I would have to cross any red podded back to a decent snow pea.

I grew out some of the F1 seeds last summer, planting into pots, and growing them on the shady side of the house. Only one line produced any seed. I'll report on that in another post.

Most of the F1 seed was sown in February 2012, for an autumn growout. Most lines succeeded, showing real hybrid vigour. Unfortunately some set seed while I was away on holiday, and proceeded to germinate in the pod following some rainy weather in July. I returned to harvest the seed only to find that much of it was spoiled. I threw the germinated seed - even tho it was shriveled up - into some seed trays, and was rewarded with a few dozen F2 plants that I then planted in a tight little bed on the boundary fence between my backyard and the playground next door.This was the yellowX purple podded cross, not my main focus. But this line has just started to produce pods, and I've got a nice half red plant, and this morning I noticed a fully red pod on one plant. As a bonus, one of the plants has produced what appears to be a nice big yellow snow - not at all what I was expecting from this line.




The second line that pod-germinated was the yellowXsnow cross. Again, I chucked the seed into a tray, not expecting much, and planted the resulting F2s into another fence bed beside the hothouse. This seems to have produced at least one attractive looking big yellow snow.

Looking forward to the next few weeks as the rest of the plants come on stream.

And I've also got huge amounts of seed from multiple lines to explore next autumn, if I can find room.




27 October 2012

Red Podded Pea Project

Inspired by Rebsie Fairholm's discoveries of a few years ago, I thought I would set out to intentionally create some red podded lines of peas. I crossed 'Golden Podded', a not very nice yellow podded 'snow' pea, with 'Purple Podded'. I've quotation marked Golden Podded, since it doesn't make a very nice snow pea, and I'm not convinced it carries both of the genes for low fibre.
Anyway, the F1 seeds of the cross were sown in late summer, and I grew them out over autumn and winter. I went away for holidays in winter, and when I got back the peas of this cross - and a few others - had matured, and the pods were hanging in the drying plants. But when I removed them, lots of them had shrivelled roots and shoots curled up in the dry pods. They had sprouted in the pod, probably following some damp weather while I was away.
Rather than throw the lot out, I salvaged what I could, and anything that looked like it had sprouted was sown into a seedling flat. To my surprise, lots of these sprouted into healthy plants.

Since this wasn't one of my core projects, and I wasn't sure how they would grow, I made a new bed along my fence with the next door playground.

They have been growing for a couple of months, and just started to flower. The F2's are segregating for pod colour
Purple and green

yellow,
half purple,




and half red!
Note the pale bracts.
A couple of weeks until I can be sure if any of the low fibre genes have carried over.
There are still a few plants I'm waiting on to set flowers, so there might even be a full red lurking in here.
But this red blush is a most exciting development.



09 October 2012

It's getting well into spring, and the last of my F2 plants are drying down their last pods. I'm so keen to try for a spring generation, but not sure if I can afford the bed space for sufficiently numerous growouts for proper assessment.

The good news is one of my autumn F2 growouts from summer grown seed has produced a half purple snow! As a bonus, it's sweet as well. I've only got about 12 seeds off it - powdery mildew has really hammered the winter grown plants.

In my impatience, I've sown 3 seeds of this Plant 6 half purple, just to see if it is homo or heterozygous for half purple. I know, too small a number for any real assessment, but if i get a green pod plant out of the three I've sown, at least I know its hetero.

I've also sown 10 seeds from Plant 4, a full fibered full purple plant, which was the earliest to set seed. Hoping to get at least a half snow out of it.

27 August 2012

Pea Pod Colouration in the F2

I'm growing out the first batch of F2 Snow X Purple peas. They have taken quite a while to develop pods - five months!.
And they haven't produced purples in the ratios I would have expected - but more on this when I do a final tally.

Of interest today is the way the purple colour is distributed on the pods. One plant has given pods that are mostly purple

 The next is mostly purple, but with green areas





...and on another plant, complementary colouration, what I'm calling 'purple dusted'. Neat how the two genes fill in each other's gaps to get full purple.

25 August 2012

Pea seed emergence

Over the past week have sown half of my F2 seeds of Chamber of Death X Purple Podded (select organics) - I'm holding half back in case of failure.
The seeds had segregated, for purple dusting, tan, and green, all with several degrees of dimpling, so I germinated them seperately in ziplock bags on a heat pad. I was hoping that the seed coat colour would help me select for purple coloration on the plants, saving me garden space for growouts. There has been considerable differences in germination rates, with the purple dusted germinating the quickest, then the tans, and the greens, of which there were the fewest seeds, have only had one germinate so far.
It seems that seed coat colour might be linked to late emergence.

24 August 2012

Re-thinking crossing strategies

Well its almost a year since I germinated my first peas to develop an antipodean purple snow pea. And I've had a chance to take stock. I dived in, without thinking through a strategy to optimise success. In part, this was due to some time pressures - rationally assessing each variety, sitting down and thinking through possible crosses, and then waiting another year to do the crosses just didn't fit with my impatience to get cracking. So I sowed every purple. yellow and snow I could lay my hands on, and crossed as much of everything with everything else that I could, given the constraints of time and available flowers at the right level of maturity.

Problem is, I now have not quite enough seed of any one line to really explore the F2 outcomes, and too much seed of multiple crosses to be able to grow out with a good chance of success this season.

A smart approach would have been to select one purple (since my guess is the three purples available in Australia are probably all the same anyway), choose a good, tasy, disease resistant, dwarfing, multi flowered snow pea of good taste, and do multiple crosses between them to get a big whack of F1 seed to grow out over summer, with a resultant 300 - 400 F2 seeds of one line to try in autumn.
Instead, I've got (or will get) about 100-150 seeds of about a dozen crosses - not quite enough to be confident of getting the desired class in one season, which could be refined , stabilised, or outcrossed for missing phenotypes in subsequent generations. It looks like I will need a few extra generations to get the classes I want, so leaping in without proper planning in an effort to get results more quickly may have backfired. This season will tell.

While the summer growouts did give some F2 seed, even sowing these as soon as I got them didn't really give me enough time to grow out the F2 plants for F3 seed this spring - my plants are just setting pods - they were very slow over winter, and some flowers didn't set seed during the winter cold - and now is when I should be sowing the next generation to escape the hot November when seeds won't set, but the pods on the F2s are onlt just developing. Let's hope for a long spring (but with an El Nino expected, I don't like my chances).


08 August 2012

Purple podded snowpea - the next generation

The first of my winter growouts of my F1 plants are just finishing off, and I've been harvesting seed. I've been away for a month and half, and some pods matured on the plants, with the seeds inside the pods germinating in the pod - most disappointing. But I seem to have enough (more than enough, actually) to get a good crop of F2 plants to assess.

For one cross, Chamber of Death X Delta Louisa, I harvested seed last week. Subsequently inspecting the seed, I noticed 2 classes of seed - wrinkled, which are blocky and wrinkly; and dimpled, which are mostly round with only a slight dimple in the seed coat. When I harvested the seed I put it down to early harvesting of pods, and thought the wrinkled ones were just under developed. But I don't think so. Wrinkled seed coat is associated with sweet flavour (I seem to recall that it's got to do with starch development which affects both flavour and how the starch gets 'packed' in the seed).

When I had all the seed spread out to select for my spring growouts, I started separating them. They definitely fell into two classes. The F2 seeds are on the right, and the original parent stock seed is on the left.
I'm going to sow them separately, to see if they segregate for flavour.

I subsequently googled this, and found wrinkled seed was one of the characteristics Mendel used in his original experiments. It's also a embryonic trait - you can tell if the F3 plants will have the gene by looking at the seed off the F2 plants. This helps if you want to select for sweetness, and want to limit your growouts, both of which I want. But I'll see how I go growing both for this line, to see if it works out.

My other F2 growouts from my summer growing seed are just setting pods now - I do have some purples, but can't tell if they are snows, yet. All of my plants are suffering from powdery mildew, and it might be a bit late to spray with Potassium Bicarbonate, but I will give it a go  this week.

17 June 2012

New colourful potatoes for Australia

Just came across this report on the ABC website about new colourful potato varieties imported by a grower in Tasmania, namely Amarosa a red fleshed spud, and Purple Bliss, a nice looking deep purple fleshed number. Should provide some fun new genetic material to play with when they get released, but it might be a couple of years before they hit the market.

16 June 2012

Winter pea sowing :(

I've been away for a couple of weeks into the far north west corner of New South Wales into the Strezlecki Desert and the Bullo Overflow chasing grass wrens (another crazy obsession worthy of its own blog), but before I left I harvested half of the crop of mature, but still green pods from my Chamber of Death X Purple podded F1 plants. I quickly dried them down over a couple of days in the dehydrator, and sowed them hoping I could squeeze an extra generation into the growing year.
I'm somewhat limited for space, and thought to utilise the ground along the back fence where my espalier apricots are now dormant - and hoping i could get a F2 generation growout setting pods before the leaves set on the apricots in spring.
But last night checking the 80 cells I sowed them into in the greenhouse, only one tiny shoot has appeared. A bit of careful excavation revealed some rotten seeds in the cells - most disappointed.

08 May 2012

Developing tubers on the TPS seedlings

Yesterday I potted on some of the TPS seedlings from the cell trays. The cells are about 3 cm cubes, and the plants were getting 10 - 15 centimetres high. I was surprised at the size of the tubers that were developing in such a relatively small amount of soil. The seeds were sown on 3 March, so about two months ago.

Without really poking into the plants I couldn't really determine what the tubers were like, but one had enough showing to indicate that it had a purple end.


Most of the others from what I could see were just straight white spuds. Hoping I can get some of the tubers to grow a bit bigger. Looking good for next season.

25 April 2012

Purple snows, homo and heterozygosity and seed sources.

All the written material says purple pod colour is determined by 3 dominant genes, A,Pu, and Pur - so I'm trying to figure out what is going on in my purple podded snow pea crosses.
I grew 4 different purple poddeds last spring, and crossed them to a range of snaps and snows, some of which carried the A (anthocyanin) gene - they had purple leaf axils, and purple flowers.

Of the purples, two (at least) were indistinguishable, although from different seed companies - Lost Seed Co, and Select Organics. The F1s from all these crosses should all have purple pods, if the parents were homozygous. Not so. One of the F1s has big green snow peas developing. I figure that was one of my hangover crosses, and in the tangle of stems and shiraz induced fog, I've accidentally crossed two green snows by mistake. Ah well. But of the proper purple crosses, one of the F1s bears lovely deep purple pods, but the others are dappled purple.
My guess is the deep purples from the Lost Seed Co cross, were homozygous for A, Pu, and Pur. But somehow, the Select Organic parents weren't homozygous either for Pu or Pur, the two genes for expressing purple colour in pods. I grew 6 plants each of each purple parent, so would have expected at least one of the parents to show dappled pods if they had been heterozygous. (This happened with one of the six Angela's Blue, which exhibited just such a trait).

I'm not sure if I used the same parent plant for each of the SO crosses, but both of the SO crosses are exhibiting this dappled purple trait.
I could grow out the original seed again, but rogues wouldn't necessarily show up - if they are heterozygous, they will still be deep purple even if a non-purple recessive was lurking in there. A smarter move would be to grow out the (uncrossed) seeds I collected from these parent plants to see if they segregate for deep and mottled purple. That would be a clincher. Will have to see if I have room - I'm rapidly running out of garden beds, with all these growouts, and hundreds of F2s potentially to be grown next spring.

16 April 2012

Sugar snap breeding resources


I've been delving around looking for pea breeding resources. There are a couple of good demonstration videos on how to physically cross peas. Rebsie's video is great, and I recently found this YouTube resource as well.

A great resource is "Origin, history and genetic improvement of the snap pea" by Myers Baggett and Lamborn in Vol 21 of Plant Breeding Reviews - but this can be a bit hard to find - my library doesn't have access, and I had to go to a Melbourne University Burnley campus library to find it.

Another good paper is "Inheritance of Stringless Pod in Pisum sativum" by Rebecca J. McGee1 and James R. Baggett.

But this video of a recent lecture to an organic grower's' forum in the US, about sugar snap pea breeding is a beauty, at least for the amateur breeder. The sound is pretty questionable, but the information is invaluable, particularly the final slides on back crossing stringless sugar snaps.

 


I'm particularly interested in the information that Sugar Ann is a stringless variety - great news, since I've got some seed, and even better, seedlings. My purple podded pea project has just taken a new turn - stringless coloured snow peas. The poor productivity of Cascadia in their trials is also of interest - I was going to use this as a new parent for breeding, after tasting them at Annie Smithers restaurant. The restaurant sources much of its supplies from their own edicated market garden in nearby Malmsbury.

So I'm growing out my first F2 purple X snow crosses - and I'm cogitating on how I might apply this new knowledge - will the Sugar Ann flower in time to cross to the purple snow F2s? If I do find a purple snow in these F2s (and that is a bit problematic), should I cross it to Sugar Ann, or perhaps one of the other tasty snows or snaps, or should I wait until the F3? This might be all academic, if I don't get any coloured snows.


how to cross peas video

Did a search today, and came across this you tube video on pea breeding. While I think Rebsie Fairholm's is a bit better, this is worth a look. And check out the tendrils on these field peas!

15 April 2012

Flower number in peas

The John Innes pisum genetic database indicates there are two recessive genes that regulate flower number, fn and fna - "Fn Fna is one-flowered; Fn fna and fn Fna two flowered; fn fna three-to several flowered". Other information I've read (but I can't remember where) suggests this is mediated by environmental conditions. [Note: when JI write Fnfna, they are talking about homozygous genetics - such a pea would actually be FnFn fnafna, bt they shorthand it, as I will, mostly, throughout this post.]

My growouts indicate this is a bit complex. My original varietal growouts were tightly planted - so they were subjected to some environmental stress, but each variety was replicated, and results were consistent. Some varieties had alternate double flowering - the first internode was single flowered, then double flowered, then single flowered up the stem. All of the purple podded plants were exclusively single flowered, as were most of the tall snow peas. Some varieties were consistently double flowered, and none had more than two flowers per node.

This would suggest that all the purple poddeds are FnFna, that the alternate flowering varieties are either Fnfna or fnFna. But what about the consistently double flowering varieties - are they multi flowered, and environmental stress has forced them back to double flowering, or is there something else going on here? Perhaps  either fn or fna is responsible for alternate doubling, and the other for the consistent double flowering?

For the record, one of the most consistent double flowerers was a Nepalese accession, simply labelled 'Salahi' (which I think is a transcription error for 'Sarlahi' but I'm letting it stand). The others were Swiss Giant, and Golden Podded. All my lines I'm assuming are homozygous - that is I'm assuming that these lines have been inbred for a long number of generations, which should result in homozygosity. So, my crosses between multiflower snowpeas (which should be fnFna or Fnfna) and purple poddeds (which should be FnFna) should yield heterozygous F1s in the recessive genes - they shouldn't be multiflowered.

[To spell it out in longhand, a multiflower homozygous pea should be fnfnFnaFna for example - or FnFnfnafna, but let's just go with the first example. The single flowered purples should be FnFnFnaFna. An F1 cross should yield FnfnFnaFna - no homozygosity at the important recessive fn locus. The same would hold for the othermultiflower gene or even in the case of double recessive fnfnfnafna - if I had it.]

So how come some of my F1s are multiflowered? One, Chamber of Death X PurplePodded (Lost Seed Co) has some alternate double flowers in the F1 - but my records suggest they are both single flowerers. This is a curious phenomenon. Stay tuned.


14 April 2012

Saffron

I've been trying to grow saffron for about 10 years. I started with some small, 1 centimetre bulbs in a mesh pack that cost about $3 each from a domestic nursery. Not having any experience with them, I tried thm in a pot. They sprouted leaves, grew, and died back in spring, just like they were supposed to, but never a flower. I persisted for a few years, with only one flower. I came home from a trip, and Ms T remarked that 'that pot of saffron had this lovely purple flower on it, but it died off' - my only chance to harvest three saffron threads, gone.
I kept growing them, supplementing my stock with the occasional purchase when i saw them for sale, planing them, removing them every spring to store the bulbs, replanting every autumn, getting more daughter bulbs, but I never got any bigger than about 15mm across, and no more flowers. Then a couple of years ago I posted on the Ozgrow forum, and one member had a source for good saffron - he was amazed that i had been paying $3 a bulb - he could get them wholesale for $1 each. I ordered a hundred, and got these huge 3 cm diameter bulbs - fantastic. So last year I dedicated a whole bed in the vege garden, and picked maybe a dozen flowers - 36 saffron threads, a king's ransom! But even better, from my 90 big fat bulbs ( I gave 10 away) I harvested about 70 big bulbs, the same number of 2 cm bulbs, and several hundred daughter bulbs. I started dreaming of a saffron farm....

Digging them up every year is problematic. They have no chance to establish big productive clumps, so the chances of a useful harvest are slim. But where to put a permanent bed? Sunny spots in the backyard are at a premium, and the house shades some of the beds in winter. A thin curving bed beside the clothes line had nothing in it, and probably gets enough sun. Done!

Planting depth is also critical for saffron flower production - deep planting gives less daughters, but more flowers. Some of the suggested planting depths in the literature are daunting - 25 cm, for a 3 cm diameter bulb sounds excessive. But saffron climbs through the soil over several years - I think daughter bulbs are produced above the mother, so over the space of 4 or 5 years the bulbs can become much shallower, reducing the flower crop.

So I undertook a trial - the bulbs have been planted in consecutive short rows - 3cm bulbs, 2 cm bulbs, 1 cm bulbs, at 3 different depths in each row - 20cm, 15 cm, 10 cm. I planted on the 18th of March, and picked the first flowers this morning, 14th of April. It will be  interesting to see where the most blooms emerge.

You can see the filaments of saffron emerging from the flowers in these pictures. Now I need to figure out a way to dry them at optimum temperature. Recent research at the University of Tasmania indicates high humidity drying (?) at around 80C - 90C is optimum for preservation of flavours and aromas.

10 April 2012

Baby Tuberising TPS

Finally got some time yesterday to look at the seed tray my TPS were sown in, back on 3rd of March. About a week or 10 days after sowing,  I pricked out tiny seedlings from half the tray, about 20 or so, some into square tomato seedling pots, and some into some disposable cell trays. They were planted deep, only half filling the pot, leaving space to 'hill up' the plants, which is supposed to encourage tuberising.  This is important - to get these little plants through the winter is probably going to be a bit of a struggle, even in the greenhouse. The tubers can be stored until next spring, when i can plant them into the garden. It will also allow me to assess colours and form to some exent, prior to growout.
A quick look over the tray didn't reveal any stand out foliage differences - I was thinking that 'Pinkeye' might not have much diversity in the line. A more considered inspection did reveal differences in stem colour - some were green, some with a tinge of red at the base, and others with more substantial colouring up the stem.
The stem colour was not really apparent in the early ones I had pricked out. I haven't done a count, but it looks like the early germinators are mostly pale stemed. This might just be coincidence.

I was a bit surprised when i started excavating the seedling tray to find the plants tuberising. Some reports on potato forums suggest this can be a bit difficult to initiate. I was even more chuffed to find one tuber with colour.




Another point of interest was that some plants were stolonising - sending out above ground runners. Not having grown TPS seedlings before, I don't know if this is usual or not.

 Interestingly, the potted up seedlings seem not to have developed tubers. I only unpotted one plant to look, but couldn't see any tuberisation. Things are looking good for next spring.

06 April 2012

A Parsnip Project Post

As I posted before, Ms Templeton is partial to a roast parsnip. But my soil is hard, and not particulalry conducive to growing long root vegetables. With carrots, I can choose a short or rounded rooted variety, but in Australia, the number of parsnip varieties generally available amount to one - 'Hollow Crown'.
A bit of a search showed up a bit more variety - Eden Seeds (and a few others) does 'Cobham', my local nursery carries Vilmorin seeds, who sell 'de Guernesey", and the big box store had a couple of different varieties - 'Yatesnip' from (surprise surprise) Yates, and 'Gladiator F1' from Fothergills.
And I recently came across 'Melbourne Whiteskin' from Southern Harvest in Hobart. But no short, fat parsnips.

Some of the North American specialty seed catalogues carry a couple of promising lines, but few export to Australia (Pastinica sativa, parsnip seed is an allowed import in Oz). 'Kral' is a short fat Russian variety, and 'Halblange Weisse' another, presumably from Germany. A friend from Homegrown Goodness was kind enough to forward some 'Kral' from Heritage Harvest Seed in Canada and, after much delay, hoop jumping and a flurry of emails, I received Kral and Halblange Weisse from Adaptive Seeds. While these are still wedge-shaped, they have most of their mass in the shoulders of the root, so seem good candidates to start a search for short fat breeding stock. Ideally, I would have liked to get hold of 'Halfback' but I can't find a source (let me know if you know where I can get some).

Another problem arose. Parsnip seed is notoriously short-lived, and germination was patchy to say the least. (Three cheers to Sarah at Adaptive, who, when I reported no-show from their Kral, instantly took it down from their website until they had done a followup germination test. That's ethics!)
Growing out parsnip seed is going to be problematic. Parsnip seems to suffer from inbreeding depression - you need to let a couple of hundred plants cross to maintain vigour. Because of the short viability, you can't grow out half the seed one year, then grow out the the other half and mix the seed lots - the older lot won't contribute much genetic material to the population since it won't be viable. Add to that the biennial nature of parsnip (it grows roots one summer, then seeds the next) and this is turning into a fairly committing enterprise - lots of selection work, lots of gardenbed space, and lots of time.
I'm hoping to do a bit of seed increase to start off, so I've sown seed late in summer, hoping for enough root development to get them through winter and develop some flower heads late next spring. With a bit of luck, I might even have enough fresh seed to share.
I'm also thinking of letting a bit of crossing happen - get a bit of fresh material into the Kral and Halblange lines, so a bit of phenotypic variety gets going, and maybe some hybrid vigour.







While you are not supposed to transplant parsnip, but sow it in situ, due to forking and distortion of the roots, since I'm looking for a seed crop rather than pretty roots, I've sown into some plug trays in my greenhouse, just to make sure I get some plants - I didn't want to risk all my hard won seed to the vagiaries of my vege plot, where a single scorcher of a day could wipe out the whole population.





With autumn coming on and the days being less intense, I chanced the rest of the seed straight into the bed. Some damp hessian cloth over the bed, and attentive watering (thanks to Ms Templeton in my absence) has resulted in lots of little parsnip seedlings on the way.