Thursday 19 December 2019

Airborne weeds: creeping thistle

Mainly about thistles

Fluffy fiend
It has been my wont to quote ‘One years seeding - seven years weeding’ in my effort to encourage gardeners into a cycle of virtue where weed control becomes easier as the years pass.

The prettiest of the dreaded epilobiums
My cosy symbiosis has now been shattered  as I suffer airborne invasions of thistles and epilobium. I have written about epilobiums extensively before but now for me personally there is a new kid on the block, the dreaded  creeping thistle.

Invading epilobiums
Come back to haunt me is the occasion when I wrote about airborne weed seeds blowing into Bolton Percy cemetery from ‘dirty neighbours’. It was in an obscure specialist magazine which unfortunately I showed to one of the newspapers that at that time descended when the churchyard was famous  One quoted me verbatim and a local villager enquired as to who those neighbours were!

I have always been aware of the minor inconvenience of airborne dandelions and its relatives and the need to spot treat them in my lawn at least once a year. 
Epilobiums have always been a curse and I wrote recently that more than half my weed control time is taken up by that pretty weed.
Peter W. recently brought to my attention how light weed seeds such as annual meadow grass just blow in from everywhere and  superficially surprising weeds are tree seedlings from such as winged sycamore seeds that cascade down.

High on the horizon now
As for thistles, they have not been on my horizon and have thought of them as agricultural weeds that invade such places as poorly managed horse paddocks or old abandoned allotments. Not any more!

Pretty self seeding plants that are NOT airborne are more of my thing
Although today I complain about two plants with natural flight capabilities, weeds can spread in other ways into our gardens; not least those carried in bird and animal droppings. Indeed many of us have acquired valuable plants such as daphne this way. I suppose in extremis most seed is capable of carriage by strong wind. When you think of it it is perhaps surprising how little some weeds actually spread.
I wonder what happens if you have a massive seed source immediately next door?
Now I know

Why my weed control is becoming harder
I have acquired a massive thistle seed source next door!
The eight acre field that borders two sides to my garden three years ago came under new management. It is now home to pheasants that are raised for shooting. I have now no need for peacocks to decorate my garden - and for that matter rabbits are even more of a nuisance (not sure about the moles).
In the last three years, parts - but not all - of the field have  been ploughed twice and also at the end of the season the coarse vegetation mown to the ground ( a temporary treat). Other than a small area of maize (pheasants love corn) no crop has been sown and weeds are given free reign and some such as fat hen  (chenopodium) are actually encouraged.
It is really interesting the ecology that is developing. There are very few pretty wild flowers but plenty of coarse ones. There is no woody intrusion as the mowing suppresses such plants.
Creeping thistle is having a field day!

Seeding everywhere for a couple of months
Epilobium girds its loins to invade from next door
To compound the deterioration of my neighbourhood environment former pasture on the other side of my garden for several years now has increasingly been taken over by prolific free seeding epilobiums.

Creeping thistle Cirsium arvensis 

Its aggressive root system might spread in at ten metres or more a year
Don’t tell me that our worst weeds are evil aliens, creeping thistle is a european native and is up there (or perhaps down) with the worst of them. Not only does it invade with vigour vegetatively it does so also by seed.
Most nasty vegetative perennials such as couch, ground elder, Japanese knotweed and bindweed set no or very little seed. Creeping thistle is not only equally vegetatively threatening but produces huge masses of seed  which is prolific and windborne. 

Once established creeping thistle spreads laterally with great vigour and its speed of travel outpaces all others. It is a long lived perennial, government certified as noxious and subject to statutory regulation (sadly unenforced these days).
A single strong plant has been shown to spread into clean land previously lacking competition up to ten metres a year. A ‘single plant’ is a bit of a contradiction as with such a rate of spread a field might contain contain several huge single clones. The only slightly good news is that half of the plants will be males (which produce prolific pollen but no seed) and some of the copious thistle-down from the females is not always fertile.
Thistle seed germinates at almost any time of year but especially in Spring.

Subtle invasion

And sneaky establishment
Thistles and me
The problem has crept up on me. Hitherto I have been complacent and although I have for two years now been stopping invading thistles in their tracks  by spraying the edge of the field their thrusting roots and rhizomes are becoming more persistent.
(The owner of the field is a lovely old man - er younger than me - and has no objection to my effort. It’s always best to tackle invading weed ‘the other side of the ‘fence’ - with the owner’s permission)

The seed is a new problem. It is only last season that I have started to notice and find thistles popping up in unusual places. My glyphosate kills it of course in open spaces but plants appear in hidden serendipity places and if I miss one it can initiate it’s vegetative spread
The strength of thistle seeding has increased almost exponentially over the last three years as it has built up its strength in the farm field. Now I watch huge masses of thistledown drift gently over my garden July to September
Epilobium is still my very worst weed  - but I wonder how long?

I am also starting to have trouble with windblown sowthistle -not to be confused with creeping thistle but a real nuisance as it is not very sensitive to glyphosate

Control of creeping thistle
Actually in a field a farmer has got a great weapon and so may you in an overgrown paddock. Just let it go rampant up to full flowering before seeding and then mow it. With all it’s energy directed into seeding it is very vulnerable. This will not completely eliminate it but this will get you well started and if repeated each year keep it under a degree of control (I chose my words carefully as I am hedging my bets)

If your thistle is in grass or lawn, standard MCPA or 24D weedkillers are effective after a few repeat treatments. Search my blog for posts about them.
I used MCPA as farm product Agritox in my post about nettles in Cathi’s field. There was also a corner of creeping thistle which I casually zapped with unused spray from my knapsack. It really hit it but as this was just a casual gesture and not repeated it is back now,

When strong intact thistles are sprayed  with glyphosate - perhaps best at 1 in 40 dilution of commercial product - it kills thistles well. Again inexperienced gardeners should search my extensive articles on how to use it.

I await germinated thistles with intrepidation next year.

Not to mention sowthistles in Lyndi's field

Sadly my anxiety is as nothing compared to the consequences of this!


Read about my 'willow herb' problem
I wrote about the nettles in Cathi's sheep paddock

Saturday 7 December 2019

Passing three million

Not so dizzy heights
Cathi, blogmeister and young Crumb who parrots the prose
I check my blog statistics from blogger every day. Sad really. Initial pride has dissolved into habit and indeed my figures have been static for several years now. It is useful to see what my readers are reading and I can try and write what might be popular but other than that my numbers do no more than satisfy my ego.
As I now approach a total of three million Cathi insists I recognise the occasion and Peter has thoughtfully suggested we go out for a celebratory meal. Fortunately a few of my friends do read me but it is very few. Isobel still promises to have a first look but she is busy and Jackie will one day get round to asking John to bring up my page. Brenda never reads me and now has the excuse that her macular won’t let her. At least that gives me the opportunity to make loving digs about her or very rarely give vent to her wisdom.

Believe it or not this was the morning of our wedding day
It’s a sort of addiction. I was originally inveigled into it by Cathi and Harry to share my gardening knowledge. Cathi as major domo for York Publishing even knowing I had never written before, set up the blog for me and Harry showed me how to work the apple computer and process the pictures. It had been thirty years since I had used a camera. Harry despaired I would ever achieve fifty readers a day and he laughed at his window when I miss-held the camera.
Apart from any element of self promotion I think there is a dearth of real horticultural knowledge in the vast amount of shallow and sometimes incorrect, amateur, endlessly recycled, gardening literature. I felt I could make a contribution injecting into gardening lore the kind of information we gave our students. There are too many myths I wanted to challenge.

A stumbling start

Harry holds a sparrow hawk
At first I thought my posts ought to be short and concise and carry relatively few pictures. Wrong. It took perhaps my first hundred posts before I strayed into a more relaxed and expansive style. Perhaps too far but Peter Williams assured me that if a post was worth reading there ought to be some meat in it.
My first 74 posts were actually posted by Cathi from my draft ‘Pages’ document. She even, poor girl, placed my selected pictures and put in the captions. (I eventually realised that the dialogue of the captions  and placement of the pictures was so much part of the story)
I of course wanted to get my message about not digging-over over (please excuse the pun). With so many individual strands to the argument not usually tackled in generic articles I wanted to be specific and I started two parallel series - reasons to dig and reasons why not. Only intrepid early readers lasted the course!
People who now come to the blog expecting to find it to be all about not digging are these days surprised to find very little about it. I do still like to throw in sly little bits of propaganda but I don’t really want to too much to repeat myself. It is still all there in the archives!

My blog got off to a great start thanks to Harry’s pictures. He was an amazingly talented photographer and gave me access to all his pictures. Without them I would have never really got going. We were lucky to get some wonderful photographs of a sparrow hawk that Harry had rescued from my garage. It was me that actually clicked the camera as he cradled the defiant bird.
With Cathi’s promotion that post was for me  a very big ‘hit’.  Cathi has always been my secret weapon and she still promotes me all over the place.

The changing blogosphere
Even in the six years since I started, I get the impression that blogs have changed. Apart from the commercially successful blockbusters that have more readers in a day than I have had in a lifetime I get the impression that as far as gardening blogs are concerned there are not so many around. It seems to me that the urgency of modern media and its multi-directional flow gives more success to sharing gardening information. Indeed most successful gardening blogs seem as a requisite be littered with links to Facebook and similar; half a dozen media platforms and more. I am afraid I cannot be bothered to supply a similar service although I must confess in the early days I did trawl Facebook sites promoting myself by making comments related to gardening and nature.
More than half of the wonderful gardening blogs that I once regularly visited are now dead or dormant.
My own reader numbers remain fairly constant and to my surprise vary little with season. No doubt many readers have left me and new ones arise. It is a bit of a dilemma how much I should repeat old information. I suppose like the gardening magazines I endlessly recycle.
One fascination is how my old posts have a life of their own and a few are read regularly and achieve astounding numbers. Some that when published were hardly looked at are now read more in a day than in the first six months!
On the other hand some that were originally popular are now never read at all.

Producing a post

Harry Poole picture of 'Piff'
It would be nice to think they were just dashed off on a whim. Not even close, my posts undergo a period of gestation. Every morning  I get up at about seven, do several kitchen chores, feed and water the bird who then alights on my shoulder. As I write now he is dictating my prose.
Still in my pyjamas I sit at the computer and blog for an hour. A post starts with a germ of an idea. Goodness knows where it comes from. Usually it is the most current bee in my bonnet.

Peter Williams provided the pictures for this popular post
Sometimes the prose flows and the verbiage appears in a couple of  sessions. More often it takes several days to get the first draft.
I allow myself another couple of sessions to assemble the pictures and carry out any editorial chores. Ever so rarely I might then give myself a day off from my obsession. The post then goes into purdah as I take the next post off my desktop. My friend Peter who produces his wonderful articles to a last minute deadline cannot believe I have four posts in stock! Perhaps that is why they are so out of date.

I next edit the new post off the desktop. By now - (on a good day) - a few new ideas have emerged and some of the old ones suddenly seem garbage. It next takes a couple of sessions to cut and paste the prose onto the blog, place the photographs, write the captions re-editing as I go.
With intrepidation I press the button to go public. Will this be the one that eventually destroys my reputation?
It takes an average of ten hours to produce each post. Why on earth do I do it?

My top posts

I was tempted to do my all time ‘top ten’. Unfortunately many  are already reflected in those at the top of the post which records the previous month. I assume many new readers just click there and keep the popularity going.
Instead I shall take samples of the most popular posts in order from the beginning. What I thought blockbusters at the time boast now seem relatively small numbers. They just did not stand the test of time as the thread of self generating publicity weakened. Unless a title brings in new readers from search engine ‘finds’ it fades out of attention.

1. The sparrow hawk came to dinner
Already mentioned today this post has only only been read 5000 times. It seemed so much more at the time. Ironically in contrast the very next post ‘corn marigolds’ has been a sleeper and accumulated 8000
2   Harry Poole pictures.
Harry was a superb photographer. Multi talented he was just as happy changing a washer or building a power station. His pictures were really what got the blog going. This very short post links to several of his very fine pictures. I has only been read 2000 times

3 An ubiquity of sparrows
This was the first real success read 178,802 times
4. Eliminating nettles. This is the first post to achieve many readers because it answers a question that many folk search for. 162,766 readers
5 A congress of corvids
Still in the top ten it is also based on Harry’s pictures 155,000 readers
6. When I wrote about Harry and Cathi’s baby rheas in the first six months it was read 63 times. It suddenly caught on and has accumulated 188,000

7 Po’s Christmas moonshine
All time winner, Po Simpson had sent me his wonderful moon pictures. 333,556 times read. We think that somehow the word ‘moonshine’ has brought in the punters.

8. Mission unaccomplished
It is difficult to know why this record of our holiday in Costa Rica topped the then current top ten for more than a year. 278,923 times read. Now no one reads it. The last reader was eight weeks ago  and was probably me!

9. Longevity in Gardeners
This is the most recent of the more popular posts and has clocked 56,000 in less than a year. I find that these days that ‘general interest’ posts like this do best 

10. Decline in bee populations
I would like to thank everyone who has helped me blog (is it a verb?). Harry and Cathi of course. Harry Kennedy for pictures of Costa Rica and worms. That lovely man Po. Alan Armitage who sends me ‘edits’ from the far north. All readers who comment and contribute their pool of knowledge. Not the spammers who never learn that their intrusions are immediately wiped.
Peter Williams has written for me the very best articles and freely provides superb quality pictures, many ‘on demand’. He is a great person to bounce ideas off, check facts and provide new ideas. The bee post which boasts 55,000 ‘reads’ is a fine example of his help.

Couch grass sprayed in December, pictured in February
11. Can you use Roundup in Winter?
Apart from not digging and soil science, I have several reoccurring themes. Glyphosate is a fundamental part of my gardening which I promote, describe and defend. My most read glyphosate post answers a question that many folk search the net for and brings them to me. 24,068


12. Significance of hybridisation 
I have an intense interest in evolution and hybridisation’s fundamental contribution. I first set out my thoughts three years ago and each new contribution to this series of posts quickly rushes to 5000. This early one has grown to 88,432

Friday 22 November 2019

Getting your minerals

Eat healthy
Spoiler alert, if you eat plenty of fruit, nuts and vegetables as part of a healthy diet there is (usually) no need for supplementation.

Once again I am indebted to James Wong for an interesting article in his column in the New Scientist that suggests to me a blog topic. He has written an excellent piece about the nutritional value of trendy ‘ancient wheats’ compared to modern varieties. I plunder his best lines.

“variety for variety compared, Canadian wheat contains ten times as much selenium to that grown in the UK”

“ boring old flour contains twice as much manganese and fibre than most ancient wheats”

“ Much research on the claimed benefits of specialist grains is supported by growers - funny that”.

It is not my intention today to talk about all round nutrition and talk about fibre, vitamins and such things. I just want to concentrate on the minerals in our diet - and their primary source, plants from the soil.

A line I will take is that our own UK soils are not seriously nutrient depleted and my worry is that possible future legislation that will seek to improve agricultural practice in terms of acting upon issues of global warming and habitat destruction might be misdirected. I just cringe when the tv news endlessly shows that silly man who keeps preaching that for the last seventy years we have been poisoning our soils. (Nominate your own culprit, another contender was minister for the environment!)

Plant nutrients
As gardeners we consider what nutrients will make our plants grow healthily.
For certain crops farmers are also  concerned which nutrients from their crop are needed by their animals. Selenium and iodine are two examples of trace elements not needed for plant growth but are paramount for the health of livestock.
We too should be concerned about mineral nutrients in the plants that we grow.

On a worldwide scale their are large areas deficient in specific important nutrients and plant breeders are working to breed crop varieties with increased nutrient uptake from  the soil.

Quick check on nutrients essential for plant growth

Gardeners will be be familiar with the major nutrients NPK, nitrogen, phosphorus and potassium.
Once called minor nutrients magnesium, calcium and sulphur are now considered major too
Micronutrients, also dubbed trace elements are (in no particular order) manganese, molybdenum, iron, copper, zinc and boron.
Some other minerals are essential for specific plant species and in other cases although not essential, are beneficial. These include chlorine, sodium, cobalt, selenium and the not at all inconsequential silicon that I blogged about recently.

Old gardeners fed their asparagus with common salt (not recommended)
I find it interesting that many minerals are ‘actively absorbed’ by plants and others are passively absorbed and in effect ‘go with the flow’ of water take up
There can be massive variations in plant uptake of minerals which vary with such as soil and plant-species or variety.
It is important to note that their are very many more different minerals that plants absorb than those they require for their own nutrition
A very important point is that farmers and growers need to ensure a supply of essential minerals to get a healthy crop and it is these very same nutrients that are important in our own diet. Many modern fertilisers contain the essential trace elements and rather than being detrimental to the level of necessary minerals in our soil as is sometimes claimed, modern fertilisers are the opposite.


Reports that UK agricultural soils are depleted of nutrients and that modern vegetables contain less minerals than historically

As to the first absolutely not. As to the second maybe and sometimes
There have recently been much hyped claims that our soils and its produce are seriously mineral depleted. Over the top and out of proportion it is worthy of investigation and over the years it has been intensively and responsibly scientifically studied.
Great ingenuity has been directed in comparing past and present. It is notoriously difficult considering such things as huge differences between mineral content of one plant-variety and another, plants grown on different soils in different countries in varying conditions in different seasons and even whether old methods of analysis are the same as those done today. Much excellent and detailed research has been carried out and I recommend if you really want to really know about these things you read the link to the Elsevier article in the Journal of Food Science 2017. It is a long piece bringing stuff together.
To be honest my head hurt as I continued to read it but as an informed honest  analysis it is second to none.

It accepts that there will be exceptions to any conclusions - there is so much variation the world over.

It shows in the round, that UK farm soils are NOT depleted in nutrients, indeed as the result of modern enriched fertilisers they sometimes contain more nutrients than before

In respect to whether crops contain less minerals there is sometimes a ‘dilution effect’ as modern high yields spread nutrients thinner. The effect is relatively small and by no means universal. The affects of varietal and soil differences hugely out distance such mineral depletion.
In counter to this, modern living has greatly increased the range and extended season of vegetables and fruit on our table all year round and the modern portion size on our plate is much greater.

I pile kale on my plate
(As to portion size it personally surprises me the small amounts of vegetables our own visitors take from the serving bowl and when eating out how much vegetable and salad folk leave on their plate.
In contrast at home Brenda insists I take my own huge helping last after visitors have taken their meagre share.
Phooey to five a day propaganda).

Do fruit and vegetables from our gardens contain more or less minerals than those from the shop? …
…and how do we maximise them?

More manky but what about their minerals?
I know of no reliable statistics about this but my own suspicion is that they are very much the same. Bare in mind that unlike vitamins and organic elements of nutrition they are not depleted in transit.

We gardeners avoid many perhaps overlooked mineral deficiencies by increased use of organic matter but recycled organic matter contains no different minerals than those available from the parent soil. It will be true that nutrients are less likely to be ‘locked up’ and become more available in those soils with higher levels of organic matter but nutrients do not come from nowhere.

In contrast purchased produce might have been grown anywhere in the world and will benefit from huge variations in soil’s natural mineral content. The presence of specific trace elements might vary by orders of magnitude depending where they come from.
In a sense if all your produce is homegrown, all your eggs are in one basket. You might just win the lottery and some ‘magic nutrient' might make you live for ever! I don’t really think so.

Some minerals are potentially toxic. I wrote about what I dug up in a failing patch in an ornamental border at home. In old properties you cannot imagine what your ancestors might have disposed of. In my case it was rusting old machinery!
American blog ‘Garden Professors’ carried an article where the writer had her soil analysed in the vicinity of an old lead painted conservatory and concluded she had better not grow vegetables there. I think she might have been a bit of a hypochondriac but no need to take chances.
I believe our own retail food supplies are so carefully monitored that toxic levels of such as ‘heavy metals’ would never happen.

Do we need to supplement the minerals in our diet?

For most of us multi mineral pills are a firm no and our varied diets ensure we get what we need.
Some folk recognise that their diets are poor and are tempted ‘to make sure’ by taking pills. Take care if any, not to take too many.
Of course some people have special mineral needs such as those who have iodine, calcium and iron deficiencies and are under medical supervision to supplement them.

Bananas are a good source of potassium
I recently checked on factors that effect blood pressure. Apparently enough potassium in our diet is important and bananas are a good source. When you feed your tomatoes with a high potash fertiliser perhaps it’s good for your heart? 
On the downside excess common salt - a source of the minerals chlorine and sodium is a serious risk. (Down with processed food and up with fresh vegetables on your plate)

No minerals here
In my piece today I have concentrated on plants. Our diets acquire many of their minerals from meat, fish and dairy. Vegetarians and vegans need worry more about supplementing certain vitamins and for all I know minerals such as calcium and magnesium which milk richly provides.
For many of us the future is likely to be almost vegetarian but with regard to lack of minerals we have little to fear.
That is not to say that there is no place for breeding crops with enhanced mineral uptakes and indeed direct mineral supplementation. Food supplementation brings its own political problems and in the UK is fairly small.
I am ever grateful that the water in Hartlepool was naturally rich in fluoride and my teeth got a good start in my early years.


As I write my post I have a morning cup of tea. Apparently it is a useful source of manganese. The other minerals do not have time to dissolve when we brew it according to research in New Zealand. The writers observed that the tea drinkers might get more (and not insignificant) nutrients from the hard water.
I curse every time I use tap water to top up my pond I get a flush of algal growth as a result of its minerals.
My old auntie swore by the benefits of emptying her tea pot onto the hydrangeas every morning. 


The Elsevier article that gives you the lowdown

I dug up some heavy metal

I wrote about mineral uptake

Friday 8 November 2019

Pictures of a church and a garden

Churchyard always open, church open all day
When David Beckham scored the goal, John Giles got the picture. As a professional sports photographer the poor man trudged the world attending almost every major sports event. World cups by the dozen!
He has been trying his hand in the cemetery garden theming the church through the year
He is married to Jackie Giles.

Jackie is the lady who leads the Bolton Percy churchyard team. Readers will recall that the garden cemetery has been restored to its finest since I hung up my boots. (Well they still dangle when several times a year they call me back to zap a few weeds)
John has been trying his hand with church photography and I am privileged  to publish some of his fine pictures.

Another fine photographer Peter Williams well known to my readers has at last got to see the cemetery garden - and sent me more pictures

I have patched together a few gardening notes to go with these fine photos.
I hope the pictures persuade any Northern readers to add Bolton Percy to their garden visits for next year. The churchyard is always  open and free and the fine 15 Century church is unlocked every day. It is worth the visit just to see the millennium window and nearby is Doylys tearoom and within  three miles Scotts fish and chips (famed in Japan) or the Sun Inn at Colton.

Still a working churchyard we have visitors throughout the year. Sadly a few fail to see the garden across the road from the church.
I planted the rose 'Nevada' forty years ago. It declined as the my rooted cutting of Leyland Cypress grew into a monster. Since the tree was cut down - the cross was carved from the trunk - the rose has thrived.
The rose is on its own roots and not grafted so there is no problem with suckers

The cross has mellowed as the wood has weathered
Abutilon vitifolium (left) is a short lived shrub in our Northern climate. It might attain ten foot high and survive perhaps ten years before its demise. It sets seed in most years which gently self sow. This is the great grandchild of my original plant.

Thermopsis is a real thug but lovely. I remember 25 years ago Jackie had me spray it out of her garden as it was taking over!
I love it.

You can see annual plants and short lived perennials are allowed to self seed. At times plants such as the green euphorbia get out of hand. I have a long list of such plants as Viola cornuta, montia and unfortunately(!) celandine that have held dominance and now are scarcely seen.
The Geranium macrorhizum has been a stalwart for forty years

Peter's pictures
After 15 years of knowing Peter Williams I finally got him to see the churchyard garden. He visited the cemetery with a West Yorkshire Hardy Plant Society group one very wet evening and unfortunately got very few photos!

You can see it was wet
Over the years my self sown birches have been much photographed as a back cloth to portraits.
My policy was that at this size or lesser I cut them back to the ground and they sprouted again. Some of the birches are in their third reincarnation

Folk always asked why the hostas were so snail free. I never used pesticides other than glyphosate
I think Gardener's Garters is very handsome

Phuopsis  is a very fine ground cover. In my day it tended to provide cover for cleavers. It is weeded out now
Euonymus is an overlooked shrub that can be pruned hard to reshape or rejuvenate. Several specimens were started by just sticking in unrooted cuttings

Over the years many fine professional photographers came to the cemetery. Indeed in the early days they beat a path to my door. Most of their analogue pictures are lost. Marianne Majerus was kind enough to give me pictures from her library for this previous post. Go to her own  website and you will find fifty more.You will find several previous churchyard posts by clicking Bolton Percy in my theme column
Most of the plants I have mentioned before. Use my search box to find them

Bolton Percy pictures on Marianne Majerus website

Monday 28 October 2019

Hybridisation is more important in evolution than we have been led to believe

How things began (for me)

I remember how I avidly devoured a series of school programmes called ‘How things began’. I want to say pre-school but on reflection it might have been in the school holidays. (On further reflection school programmes did not go out in the holidays - the timing is not a false memory).
I started a lifetime of intense interest in evolution - although  actually it was never even mentioned at school

I only formally learnt about evolution for A level biology at Hartlepool Technical college (N.E. grammar schools did not deign to teach things biological). I remember an early essay about evolution when addressing the concept of animals appearing as from nowhere in the fossil record and often remaining for millions of years almost unchanged before becoming extinct or still surviving.
I remember mentioning hybridisation as an explanation for this phenomenon of apparent sudden appearance in the fossil record. Metaphorically my suggestion had a thick red line drawn through it.
I know the conventional explanations but in truth evolutionists have always blurred hybridity over.

Nowhere in the school version of evolution did hybridisation appear. Everything was in a straight line and nature’s new innovations were never shared.
Schools still teach that rag bag of horse ancestors as if one came directly from one another whereas in truth in evolutionary terms they are not even in the right order.  If you regarded them as close relatives which sometimes got together you would be nearer the truth. (Impossible with the actual examples that are distant in time and distinct in genome). The arrow of our much beloved genetic trees would seem to be broadly true but much more meandering than generally portrayed.

Albenga and Shirley are F1 hybrids
My next foray into hybridisation was at Wye College when in a student exercise in public speaking I had to give a talk to classmates on a research paper called ‘heterosis versus variety’ in relation to breeding tomatoes. It is etched on to my mind
Heterosis is the posh word for hybrid vigour and is associated with bringing together of two inbred genetically uniform distinct parents (albeit actually close in genetic distance) where off-spring tend to be uniform heterozygotes and lacking in often inferior paired recessive genes. (don’t ask).
It requires the cross to be repeated for each new generation of seeds which suits seedsman very well.
I subsequently learned that all the advances of bringing distinct genes together can in much more expensive longer breeding programmes be stabilised in true breeding varieties.
I would imagine advantages of hybrid vigour become stabilised in evolutionary processes too

Influence of Agriculture and Horticulture

''Pink Panda' is a cross between a strawberry and a cinquefoil 
Perhaps in the popular mind creation of horticultural hybrids bare no resemblance to the process of evolution. The elementary text books would have it that way and indeed any hybrids are an inconvenient aberration.

We gardeners and farmers meet hybridised plants and animals every day and just about all the plants we grow in our gardens are hybrids. I don’t mean immediate hybrids between distinct genera and species although there are thousands of those too. Just between varieties and closely related forms. They all have numerous hybridisation events in their long ancestry, some more distant genetically but most more closely related. Just think of promiscuous aquilegia species that cross and seed themselves everywhere.

Christmas cacti  hybrids thrive in the jungle
In the popular mind hybrids are some kind of aberration. In truth they are an integral part of evolution and a means that diversity is created and shared.
It is almost universally excepted knowledge among professional botanists that half of the world’s plants are hybrids. I suppose they mean theorised from known or mooted hybridisation events over the past few thousand years. Go back through evolutionary time I believe all have been influenced by hybridisation on many occasions.

A popular illusions about hybridisation
It is less relevant to animals

 A mule is a hybrid between a horse and a donkey, A chance of  being fertile is about a million to one. Inevitably mules have been born to donkey or horse fathers
Certainly for want of a compatible partner animal hybrids have less chance to breed. The more distant the cross the less fertile a hybrid will be and such as the mule are said to be sterile (on the net you will find opposite claims). 

Primula kewensis arose as a hybrid between two species of primula and the flowers remained sterile for years before fertility arose
Plants that can propagate vegetatively can sit around longer to find a compatible mate or fertility to arise

As already mentioned most hybridisation events  are between fairly close  relatives and a substantial number are fertile.
Even rare extremely distant crosses where the odds against fertility are thousands, even millions to one might have the chance to procreate. Such odds are as nothing over evolutionary time

The most likely partner of a new hybrid is one of the parent species. If in rare events the progeny of a first or early cross are geographically isolated or in some other way physically separated they might start new evolutionary lines. New species can start this way. In fact some people think almost all new species start this way.

A new hybrid’s most likely fate is that they are subsumed into one of the parent lines as succeeding generations mate. Even though such hybrids are ‘lost’, genes have crossed over from species to species and if some are advantageous will potentially be repeatedly passed on as 'near' species mate. (A to B to C.... ad infinitum)

Thrum and pin eyed flowers which aid cross-pollination are found in a large range of very diverse families
This process is known as introgression and I believe it to be very significant. Not only significant, but in terms of millions of potential liaisons universal and common.

Hybridisation news
I try in my posts on hybridisation to report new developments as the world starts to embrace hybridisation’s evolutionary significance. The new atmosphere is well illustrated by a post on the BBC website which inspires two of the three items I mention today

1. New hybrid coral

Acropora prolifera (dig that name) is a natural hybrid that has been discovered on the sea walls in the vicinity of Miami harbour and thrives there but unfortunately is threatened where colonies are inundated with silt.
Although it is sterile this is no barrier to distribution as corals propagate vegetatively. Efforts are being made to establish it out at sea and develop efficient  propagation techniques. It is a classical example of where an environment is inhospitable to parent species - virtually all have died out - and without their competition the new hybrid can thrive. In this case being sterile there are not even backcrosses involved

2. Human ancestry

Recent discoveries of hybridisation’s major influence are being further entrenched in public acceptance by articles such as the BBC piece linked below. It provides many interesting links to recent research.
The program which mainly reports on recent discoveries does touch upon very early human ancestry millions of years ago (most evidence that can be gleaned from genetic analysis is relatively recent - perhaps a maximum of half a million years or so. The further back you go it becomes much harder to hypothesise where genes have come from).
It does puzzle me why our ‘recognised’ very early primate ancestors would have had such very long periods of stasis as suggested by the fossil record.
After all hybridisation is not new and has been happening since the dawn of sex in multi-celled organisms.

3. Docile killer bees

Thank you New Scientist for your story ‘chiller bees’
You will have heard stories about South American hybrid killer bees that are dangerously aggressive. You might have even seen films - both real and fictional stories of their aggressive ways.
It’s broadly true.
The original hybridisation was by a Brazilian bee keeper in the mid nineteen fifties He brought aggressive African bees from Tanzania in an attempt to strengthen the weakening populations of Brazil’s own domesticated european bees. Unfortunately the hybrids escaped and bred further with South America's own wild populations. Now they are found throughout and beyond South America. They are very aggressive indeed and are the sort of thing that get hybrids a bad name.
There the story might end except the hybrid bees arrived in Puerto Rica; it’s more densely populated than most other places and for bees has a hostile climate where natural selection is extremely acute. Within a decade or so extremely docile swarms started to appear. Even better they were prolific producers of honey and healthy. They are thought to have huge potential through further hybridisation to improve world bee populations. This time with necessary safeguards.
The genetics are very interesting. Apart from hybridising creating new gene combinations, what happened in Puerto Rica illustrates very rapid evolution by natural selection.
Where past hybridisation gives nature variation to work on, relatively small but significant changes can be very speedy.

The most convincing explanation is that the wild  bees  descended on this very heavily populated island where selection pressures were huge as the bees were so feared and mercilessly hunted. Only quiet ones survived to produce fertile queens.

Hybridisation is not the only means that genes cross over

The monarch butterfly contains genes from a spider
It is called horizontal transfer, where genes have wandered from the the much vaunted traditional ‘straight line’ from the first ancestor. Hybridisation and attendant introgression are the obvious cases but in primitive ‘pre-sexual’ organisms swopping genes such as antibiotic resistance is far too common.

A recent New Scientist carried details of natural transgenic plants. It claims that at least 5% of the world’s plants carry transgenic genes that have been transferred by the bacteria agrobacterium. (It does this for its own nefarious purposes and the means is fundamental to the development of CRISPR that we will not discuss here)

It is ironic that this research comes from St Petersburg university. As I observed in an earlier post on hybridisation the Russians were past masters in utilising hybridisation in early plant breeding. That’s before their pioneering genetics research was trashed for half a century by Lysenko.
The recent Russian research suggest that bacterial transfer might be a route to the development of new species.
The New Scientist article also refers to gene transfer by virus.

I was astonished at the statement in the same article that the intimate cell connections induced in plants by common grafting has been transferring genes for millennia.
That goes against everything I have been taught in my lifetime.

I am yet to be persuaded.
Interesting that the Russians claimed transfer of  information by grafting more than a century ago


The recent article on the BBC website

My 2015 article on hybridisation which refers to Vavilov the great Russian geneticist.

I have written eight articles on hybridisation linked in the theme column

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