Tag Archives: plant breeding

Meanwhile, in a New Zealand summer

In a world beset by problems, a little ray of delight can change a day. In a segment entitled ‘Meanwhile in New Zealand’, I give you this from the southern city of Dunedin:

Whether this is the same sea lion who then chased the swimmers out of the surf at St Kilda Beach the following day, I do not know. It seems a little ungrateful if that is the case. St Kilda is a big beach. John Wilson Ocean Drive is a long drive. She seems to be claiming an awful lot of territory as hers.

Yellow tigridias in the summer borders but everyone has red freckles

I have been looking at the tigridias this week. Tigridia pavonia or jockey caps in the vernacular. These are Mexican in origin, day flowers – as in each bloom only lasts part of a day but each bulb sets a flower spike with multiple buds that open in succession. They make a good wildflower or can be mixed in with other plants in a border but overall they are not a plant of great refinement.

We were given a collection some years ago and I spent some time separating them out into different colours to use in different contexts, as well as sorting out the more common spotted ones (freckled, we call them) from the ones without. The scarlet red and the yellow ones were put into the summer borders. The pinks and whites I used in separate blocks in the lily border, going from white no freckles through pale pink to deep pink with freckles at the far end.

The usual form has the freckles in the lower row.

Tigridias seem to cross readily so there is a whole range of orange tones I have seen in another garden and apparently they come in purple which I haven’t seen and surprises me because they need a blue gene to get to that shade.

My yellow ones and red ones have never thrown a freckle-free bloom that I have seen and I was thinking about this in my garden thinking time*. My theory was that if I was really intent on trying to get a freckle-free result, crossing the pure white onto the yellow should work. Ditto, crossing the deepest pink freckle-free bloom with the pure red one. The seedlings would be variable, but a few at least should, theoretically, come out in a pure colour with no freckles.

Would crossing the deep pink/no freckles with the freckled red and the freckle-free white onto the yellow likely lead to seedlings in red and yellow without the spots, I asked Mark

Fortunately, I have a resident plant breeder to hand and he confirmed my theory with the proviso that it depended on whether the freckle-free white sets viable pollen. Sometimes mutations can be sterile – genetic blind alleys.

I prefer the purity of the blooms with no freckles. Mark does not. He has never understood why his late camellia-breeder Uncle Les Jury spent time trying to breed out the freckles. He told me the story of when he was a small child and a tigridia flowered in the rockery in front of the house. His memory is still so vivid that he gave me the exact location of it in the rockery and he still recalls looking into the bloom and being fascinated by the spots. He has a childhood attachment to freckled tigridias and who am I to argue with that? He has shown zero interest in doing the crosses for me to get freckle-free yellow and red ones.

My favourite tigridia at this time

I know the process of doing it but I lack the will to do the cross, mark the blooms that have been hand-pollinated, watch for the seed to form and ripen, gather the seed and sow it and then look after the seedlings for the two years they take to reach flowering size before I see if any of the potentially scores or even hundreds of seedlings look as if they have pure colour and nary a spotty freckle in sight. It takes effort, skill and a whole lot of patience to do controlled plant crosses. I have other priorities for my time so I shall be content with keeping an eye on my existing yellows and reds to see if they do it for me. It seems unlikely at this stage but I can live with this passing disappointment.

*Apropos gardeners’ thinking time, all the feedback on last week’s post indicated that none of us are intent on using that time to come up with theories of great importance or indeed to plan great contributions to the culture of civilisation. It is the immediacy of the task in hand that occupies us and the very act of being able to focus on that task is what soothes us and centres us in our own patches in nature.  

The plant breeder’s garden

“It’s very white out there,” he said

“It is very white out there,” Mark observed. We were standing in the roller door of our large shed, sheltering from another rainy squall and looking out to the new summer perennial gardens. The photo doesn’t fully convey the white experience. The row of Fairy Magnolia White, Camellia yuhsienensis and Mark’s hedges of michelia seedlings were all in view. Mark was envisaging a carpet of snowdrops at ground level as well, even though they are but a fleeting delight. I was looking at the michelia seedlings.

Mark has planted two sides of the new garden area in michelia hedges. Technically – in accurate nomenclature – these are all magnolias now but we continue to use the earlier term ‘michelia’ for the sake of clarity. When we say ‘magnolia’ here, we are almost always referring to deciduous magnolia trees so it is confusing to include the world of evergreen michelias which also feature very large in our lives at this time of the year.

Some of the seedlings are simply gorgeous but won’t be named

When planting seedlings, it means every plant will be different. For the largest length of visible hedge, he planted out one particular cross that had not come out as he hoped because very few were coloured. The nature of the parentage means that they will flower well, not grow out of control and be suited to clipping but they will never have the precision of planting a row that is all one clone – in other words, identical to each other. Mark likes seedlings for mass plantings because it adds interest to have them all similar but not identical.

Others are pretty on their day but floppy blooms don’t cut the mustard

I paced along his hedging, estimating how many individual plants there are. Getting close to 200, was the answer, planted at about 30cm spacings because we want a quick hedge that can be trimmed as required. Each individual plant in bloom is lovely on its day but some are lovelier than others. However, none will be named and put into commercial production. Mark has already named Fairy Magnolia White and Fairy Magnolia Cream and he won’t name any more white or cream ones unless there is something that is radically different or a major improvement. So these are ours to enjoy alone.

Heading into pink 

Part of a breeding breakthrough in colour but not good enough to select

At one end, there are about three different pink-toned varieties which are something of an oddity in amongst the cream and white majority. Again, he has already named Fairy Magnolia Blush in this colour range so they will just stay as a quirky aberration in the hedge at flowering time. We are okay with quirks.

Hardy michelias are basically white or cream. While there are new tropical species still being discovered and some of those show more colour, Mark has no interest in trying to breed with them, even if we could get them into the country to work with. Most of the michelias are not overly hardy at the best of times and he has been trying to get hardier selections (will they grow well and flower consistently in places like the UK, is one of his measures) without introducing more tropical genes. But he has managed to get as far as pinks, purples and primrose yellow by ever more complex crosses using the material he has available.

From white through to pinks and purples with a few heading into pale yellow –  blooms from the breeding programme

I see it was four years ago that I set out to pick a representation of single blooms from his seedlings to show the range in colour, flower size and shape that he has reached in what is predominantly a white or cream plant genus. While he has continued to flower more since, this photo remains a fair summary. We have selected three new ones that are currently in propagation and performance trials for probable release but there is a whole lot more to selecting a plant than the just flowers. My lips are sealed as to what makes these three worth singling out until we are further down the track of commercial trials.

Fairy Magnolia Cream just coming into flower

In case you are interested in what goes into selecting a plant (or you want to name something you have found), off the top of my head, the checklist includes the following:

  • Is it either distinctively different or a major improvement to similar plants already on the market? (This is arguably the single most important criterion).
  • Are there plenty of flowers? How long is the flowering season (some can be a short flash in the pan)? Does it flower consistently well every year?
  • Are the blooms reasonably weather hardy?
  • If it is scented genus, are the flowers fragrant?
  • Do the blooms age gracefully and fall cleanly?
  • Is the foliage as good as the flowers?
  • Is the foliage in proportion to the flowers?
  • Where do the leaf buds open from? In the case of michelias, does it just set leaf buds on the tips (in which case it will look leggy and bare very soon) or does it set leaf buds right down the stem.
  • Does it ever defoliate in a wet spring (a feature of Magnolia laevifolia formerly known as Michelia yunnanensis)?
  • What is its performance like as a garden plant , not just grown in a container? It takes several years to make this assessment. In the longer term, will it stay a garden-friendly size? Does it take pruning, trimming or clipping well?
  • What is its international potential? How is it likely to perform in more extreme climates?

Only then do the propagation trials start. There is no point at all in selecting a plant that is difficult to propagate, where the percentage of cuttings that do not set roots is too high, where plants *whiff off* – Mark’s phrase meaning die – during production, or where very particular propagation and growing techniques are required for success – growers just do not want to put the time and expense into growing plants that are unreliable or too picky.

New releases used to be the life blood of our mailorder business. Some selections stood the test of time, others not so much. At least all the magnolias have proven to be worthwhile. It is the vireya rhododendron selections and a few of the camellias that have fallen off the Jury plant wagon. These days, we get a new plant through the initial selection and then we hand it over to our agents to manage through final trials and then getting it to market.

It is a long path to getting a new cultivar onto the market. But in the process, we get a lot of unique plant material to use in our own garden.

Magnolia doltsopa syn Michelia doltsopa – a selection released as ‘Rusty” by nurseryman, Peter Cave. Pretty flowers but showing typical floppy tendencies of this species and the original plant in our park is massive.

A touch of Tikorangi around the world

We are generally accustomed to seeing Jury plants growing in different parts of the world, though sometimes it generates a special thrill. A UK friend sent this photo of Magnolia Felix Jury in bloom at The Garden House in Devon last week. We had seen this particular tree growing strongly several years ago but it was summer, so in leaf, not bloom.

It takes time for a magnolia to prove itself, particularly across a range of different climates. Magnolia Vulcan has never really performed in cooler climates because it loses its flower size and blooms more in muddy-purple tones than in the deep claret-red that sets it apart here. There is always apprehension as to how other deeper coloured cultivars will perform in much harder conditions than we have. Early blooms on ‘Felix Jury’ in the chilliest climes of Northern Europe show that it retains its flower form and remarkable size, but the colour can bleach out – albeit to prettier shades than the muddy ‘Vulcan’. Whether that colour will deepen as the plants mature (which is what happened here over a period of years) remains to be seen.

This made it a special delight to be sent the photo of The Garden House specimen, showing good colour, good size and the correct flower form.

Even I found it touching to see Mark’s delight at the specimen of Magnolia Felix Jury growing a few doors up from where our daughter lives in Canberra. He felt it was like having a touch of Tikorangi in her street. Canberra is not exactly Magnolia Central so if ‘Felix Jury’ blooms as well there as at The Garden House, it will be a showstopper. The house owners were a tad surprised when I knocked on their door to ask if I could take photos and explained why. They also had Mark’s Fairy Magnolia Blush growing to the immediate left of the umbrella. Nothing illustrates the stark difference in climate to here more than an astroturf lawn.

When near enough is not far enough

012It being autumn, ‘tis the season of sasanqua camellias here. Ever since camellia petal blight arrived to wreak havoc on the later flowering japonicas, we have been a great deal more appreciative of the sasanquas. What they lack in flower form, they make up in performance.

Gay Border on the left, Navajo to the  right

Gay Border on the left, Navajo to the right

On a grey and somewhat bleak day, I thought to entertain myself with photographing the flowers but became sidetracked onto comparisons. When we had our nursery in full production, Mark would regularly make calls as to which cultivars we would propagate and sell. Would it be Navajo or Gay Border? We chose Navajo. It is not just the flowers that are the deciding factor. The habit of growth, foliage, size, performance and ease of propagation and production were also considered although the decisions were often a little ad hoc. When it came to Sparkling Burgundy and Elfin Rose, we chose the latter because its foliage looked better.

 

Sparkling  Burgundy left, Elfin Rose right

Sparkling Burgundy left, Elfin Rose right

We felt that it is not helpful to a customer to look at a range of plants with very subtle differences. “The man on the galloping horse” test, Mark calls it – the differences should be obvious, not just subtle variations. As far as we were concerned, we were professionals and customers had a right to expect us to do some filtering in selections and to pick good performers.

When it comes to naming his own cultivars from his breeding programme, Mark is hugely more rigorous and restrained. A new release has to be significantly different, distinctive or a major improvement. He has only named four of his own deciduous magnolias so far and that is out of many, many hundreds – maybe into the thousands – of seedlings he has raised. This restraint is somewhat unusual in the world of plant breeding.

Honey Tulip top left with other named cultivars. Might we have seen this as a breakthrough in flower form?

Honey Tulip top left with other named cultivars. Might we have seen this as a breakthrough in flower form?

When we released Magnolia Honey Tulip, we received an email from an overseas self-appointed expert acknowledging that Mark was extremely – excessively, some may say – restrained about the new selections that he named and released but he should not have released a yellow magnolia. The world has enough yellow magnolias already, he loftily told us. Right-o then. We knew what he meant – there are many yellow magnolias named which all look very similar, but apparently it had not occurred to him that Mark, with his self-imposed restraint, may actually have managed to breed one that was a breakthrough and very different. We did not reply.

Anybody can raise seedlings of Black Tulip but are they then all worth naming? We think not.

Anybody can raise seedlings of Black Tulip but are they then all worth naming? We think not.

A plant breeder, by our definition, does more than just raise open pollinated seed. Not so the gentleman who visited us (again from overseas). He loved Mark’s Magnolia Black Tulip which sets seed. So he raised a whole batch of seed and spawned a whole lot of similar looking flowers which he then named and insisted on showing Mark all the photographs. None looked to be distinctive, a breakthrough or an improvement. They were just subtly different, as seedlings usually are. That sort of willy-nilly approach is not helpful to the plant and gardening world but we see it often.

That is why we have never coveted a National Collection – of anything really. The UK is very big on national collections. The parent website states:

“Plant Heritage’s (NCCPG’s) mission is to conserve, grow, propagate, document and make available the amazing resource of cultivated plants that exists in the UK….

Our main conservation vehicle is the Plant Heritage National Plant Collection® scheme where individuals or organisations undertake to document, develop and preserve a comprehensive collection of one group of plants in trust for the future.”

Camellia brevistyla left, microphylla right. They look mighty similar to us.

Camellia brevistyla left, microphylla right. They look mighty similar to us.

It is one thing to collect species – that is important for biodiversity and many are endangered in the wild. Mind you, we remain unconvinced that Camellias brevistyla and microphylla are actually different species. It looks more like seedling variation to us.

"For I have seen the national rhubarb collection"

“For I have seen the national rhubarb collection”

Also the compilation and maintenance of a wide genetic pool is important when it comes to crops like fruit and veg. “For I have seen the National Rhubarb Collection”, I tweeted when we visited Wisley. It seemed such a random and esoteric plant to collect, which is not meant in any way to deride its worth. And it was certainly a beautifully maintained collection.

But a National Collection that takes in many named hybrids? We have seen too many inferior and indistinct hybrids named to ever want to start a collection of any plant genus. We would rather have plants that are selected on individual merit in our garden.

Plant collecting is like stamp collecting, Mark explained. The search for a particular named cultivar may be challenging, rewarded by the thrill of acquisition. Whether the plant was actually worth acquiring – whether it warranted naming in the first place – becomes irrelevant.

Postscript: we don’t like to dwell too much on the travesty of our Cordyline Red Fountain and the ring-in Cordyline Burgundy though this was not, we think, motivated by misplaced breeder pride but by much baser motives indeed.

Know thine species

The show dahlia

The show dahlia

You can quite easily live out your gardening days without ever worrying about species and hybrids. Indeed you can, but as with most activities, many people will find that the more they know, the more they enjoy what they are doing.

At its simplest level, species are the natural form of a plant in the wild. And all plants originated somewhere in the wild.

Hybrids are mix of two different species in the first instance and after that they can quickly become a mix of many different species and resulting hybrids getting ever more complex genetic makeup. There is no value judgement in the rights and wrongs of that. Sometimes these hybrids occur in the wild without any human intervention (usually referred to as “natural hybrids”). Often it is done deliberately to try and improve plants.

A variation on controlled hybridising is line breeding – raising many seed from a plant and selecting only the very best with which to continue. Then seed from those best plants is raised time after time until it shows stability. Seed can be extremely variable and this form of line breeding is trying to edit out the less desirable aspects over several generations.

It happens all the time with edible crops. Think how much sweet corn and kiwifruit have changed over the years. The original, wild collected species of edible crops are often poor shadows of what we have now in terms of yield, reliable production, ease of handling and palatability.

It is not always true, of course. Sometimes commercial imperatives have seen us saddled with inferior tasting product – tomatoes are a prime example. And there are concerns about the loss of the wild species which are important to maintain the gene pool for food crops.

As far as ornamental plants are concerned, most of us will have gardens which are a mix of species and hybrids. There are no hard and fast rules although I have met a fair number of gardeners in my time who parade a collection of species only as a badge of status.

Species Camellia gauchowensis

Species Camellia gauchowensis

Some species have a simple charm which is lost in their showier hybrids. Others are nondescript in the extreme. Some highly desirable species are simply damn difficult to grow whereas the hybrids bring new vigour which makes them much more rewarding garden plants. Sometimes there are species which make splendid garden plants but they can be overlooked because their names are not appealing. Camellia gauchowensis has been the standout star of that family here recently and why anybody would grow the likes of Mine No Yuki instead of C. gauchowensis, I don’t know.

We have been revisiting the camellia species as we pick over the best options in the face of the devastating camellia petal blight which has so affected many of the hybrids we grow. It is not that the species don’t get it. It is just that some of them have less susceptibility and have other good characteristics which are worth looking at. More on this in the future.

Show blooms, no matter which plant family, often tend to be over-bred hybrids which are but distantly related to original species. Dahlias which are too heavy to hold their heads up without staking, bizarre daffodil forms, overblown cyclamen or chrysanthemums, enormous begonia flowers – anything that is bigger, allegedly better or a novelty genetic freak.

Named hybrid aster at top, self sown seedling at bottom

Named hybrid aster at top, self sown seedling at bottom

But controlled hybridising can also give us garden plants which are hugely better performers. You can see in the photograph of asters that the abundance of blooms at the top are from a named hybrid whereas the few poor specimens at the bottom are from a self sown seedling which has probably reverted closer to how the original species looks.

Hybrid arisaemas for our own garden

Hybrid arisaemas for our own garden

I am of course married to a plant breeder who is driven by the desire to create better performing garden plants. Sometimes it is just to get plants which will grow better in our garden here. His work with arisaemas is of this ilk. Many of the desirable arisaemas are a battle to grow in our conditions with insufficient chill and they simply don’t come back a second year. By hybridising two different species, he can get hybrid vigour which means they are much more reliable and stronger growing.

Other plants may be hybridised to look for new or improved characteristics – extending the colour range, reducing the impact of disease, getting more compact growth, better floral display, a longer season, sterility (to avoid unwanted seeding) or bringing the best features of different hybrids together in one plant. There are many reasons to hybridise and one of the final tests before selecting a new cultivar for release is to measure it against both the originating species and the actual parent plants. If it is not a significant improvement, then it won’t get released on the market.

Hybrids have their place in the ornamental garden and in the edible garden. But in a world which is squeezing the natural environment in every way possible, we need to retain the original species for reasons of ecology and bio-diversity. The more people who understand the difference the better – even more so if they can move away from the modern “green” cliché that says the original species are, by definition, better. They are not, but they are important.

First published in the Waikato Times and reprinted here with their permission.