0:00:17 > 0:00:21I've been fascinated by plants for my entire life.
0:00:21 > 0:00:24They are nature's most innovative creation.
0:00:26 > 0:00:29And yet, what is most surprising
0:00:29 > 0:00:31is that almost all the plants that we grow
0:00:31 > 0:00:34have been altered in some way by people.
0:00:36 > 0:00:42For 10,000 years, humans have created new plant varieties for food.
0:00:43 > 0:00:46We used trial and error.
0:00:48 > 0:00:51Then, 150 years ago,
0:00:51 > 0:00:53a new era began.
0:00:56 > 0:00:59Pioneer botanists used science to breed plants,
0:00:59 > 0:01:04and set out to discover how plants passed unique qualities
0:01:04 > 0:01:07from one generation to the next.
0:01:10 > 0:01:15Botanists began to discover how plants create their astonishing variety.
0:01:18 > 0:01:22They puzzled over the colour of snapdragon petals...
0:01:22 > 0:01:26and the strange patterns in wild maize.
0:01:26 > 0:01:30Some gave their lives to protect valuable seeds.
0:01:31 > 0:01:36And together they unlocked the secrets of plants for the benefit of us all.
0:01:40 > 0:01:43The long quest to understand the world of plants
0:01:43 > 0:01:48would lead botanists to develop a new tool - plant genetics.
0:01:48 > 0:01:55Today, botany is at the forefront of attempts to rescue a rising world population from starvation
0:01:55 > 0:02:00through the production of new and improved varieties of our staple crops.
0:02:15 > 0:02:20Plants really are the most incredible living things on earth,
0:02:20 > 0:02:25sometimes simple, sometimes complex, but always beautiful.
0:02:34 > 0:02:37And what really blows me away is the sheer variety.
0:02:37 > 0:02:40Just as you think you've seen everything,
0:02:40 > 0:02:42you look at a new flower
0:02:42 > 0:02:44and you see something which you've never seen before.
0:02:49 > 0:02:53The variety works on so many different levels,
0:02:53 > 0:02:56so you have trees, you have climbers, you have herbs,
0:02:56 > 0:03:00and then within the flowers you've got the diversity of colours, the diversity of shapes,
0:03:00 > 0:03:03and then you find varieties on a theme,
0:03:03 > 0:03:07so you find members of the daisy family, you find different scents,
0:03:07 > 0:03:12so you have a plant there that smells like it's a tin of cherry-pie filling...
0:03:12 > 0:03:18and all of this variety is there to do the same thing, which is to produce more plants.
0:03:18 > 0:03:23And even within a group of plants that are clearly the same species,
0:03:23 > 0:03:26you get a variation of height and of colour.
0:03:26 > 0:03:28The diversity's endlessly wonderful.
0:03:32 > 0:03:37How does this complexity of form and function come about?
0:03:37 > 0:03:39It's always fascinated me,
0:03:39 > 0:03:44because variety among edible plants has huge implications.
0:03:44 > 0:03:47It's the key to producing more food.
0:03:47 > 0:03:50To botanists in the 19th century,
0:03:50 > 0:03:56how plants generated variation was the greatest puzzle in science.
0:03:58 > 0:04:03150 years ago, even the great Charles Darwin described us as
0:04:03 > 0:04:09profoundly ignorant of the mechanism whereby this variety was generated.
0:04:13 > 0:04:17As botanists began to unveil the mechanism behind variation,
0:04:17 > 0:04:21they laid the foundations of plant genetics...
0:04:22 > 0:04:26..genetics which showed botanists how plant characteristics
0:04:26 > 0:04:30are passed on from one generation to the next.
0:04:31 > 0:04:35It would give them the power to tamper with the laws of nature
0:04:35 > 0:04:38and the means to feed the world.
0:04:39 > 0:04:47And yet the story of plant genetics begins with something we see around us every day...
0:04:52 > 0:04:56..a concept so familiar, it's easy to take for granted...
0:05:00 > 0:05:02..inheritance.
0:05:06 > 0:05:10If you look at any population of plants or animals or people,
0:05:10 > 0:05:15you notice that each individual is different from the next.
0:05:15 > 0:05:21Each is a unique combination of the characteristics inherited from their parents.
0:05:27 > 0:05:32But how do these characteristics get passed down from generation to generation?
0:05:32 > 0:05:38This is a question that has intrigued the new wave of biologists since Darwin.
0:05:43 > 0:05:51The first pieces of the inheritance puzzle will be put together far away in the Czech Republic.
0:05:54 > 0:06:01And the evidence is buried in an obscure scientific paper, published in 1866.
0:06:03 > 0:06:08The first thing you notice about this original copy is it's not in English, it's in German.
0:06:08 > 0:06:12Secondly, it's written by a monk, and thirdly...
0:06:14 > 0:06:15..it's about peas.
0:06:18 > 0:06:22Gregor Mendel had been growing varieties of pea plant
0:06:22 > 0:06:24that had different characteristics,
0:06:24 > 0:06:29like whether the peas were wrinkled or smooth, yellow or green,
0:06:29 > 0:06:32whether the stems were tall or short...
0:06:32 > 0:06:35Plant breeders had done that kind of thing many times before.
0:06:35 > 0:06:42What was extraordinary about Mendel was he repeated the experiment again and again and again.
0:06:42 > 0:06:49And, even more critically, he wrote down the numbers of each kind of plant that he got in each generation.
0:06:49 > 0:06:52Mendel treats plant breeding as a science.
0:06:54 > 0:06:59And he spots something very odd in the numbers he's written down.
0:06:59 > 0:07:04The ratio of tall plants to short, or wrinkled to smooth,
0:07:04 > 0:07:06is always the same.
0:07:09 > 0:07:12Nobody had ever noticed this before.
0:07:14 > 0:07:20These patterns hold vital clues to understanding inheritance.
0:07:21 > 0:07:27But for 35 years, nobody in the scientific community understands its significance.
0:07:29 > 0:07:36In 1884, Mendel dies and his work disappears into obscurity.
0:07:39 > 0:07:43That is, until the turn of the 20th century,
0:07:43 > 0:07:46when Mendel would gain his greatest champion...
0:07:48 > 0:07:50..William Bateson.
0:07:54 > 0:07:57Bateson's a Cambridge University zoologist.
0:07:57 > 0:08:02Plants fascinate him, but he's more used to working with animals.
0:08:04 > 0:08:09He wants to see if he can find the same inheritance patterns in animals
0:08:09 > 0:08:11as Mendel got with his peas.
0:08:15 > 0:08:18This is William Bateson's makeshift laboratory.
0:08:18 > 0:08:22For years, he runs a series of experiments wherever he can,
0:08:22 > 0:08:25in his own garden, even in a disused church.
0:08:25 > 0:08:31This is because the authorities at Cambridge University believe his work on understanding inheritance
0:08:31 > 0:08:34is incomprehensible and therefore futile.
0:08:34 > 0:08:37So his funding is pitiful.
0:08:38 > 0:08:44Bateson's career at Cambridge had started as manager of the college kitchens,
0:08:44 > 0:08:48hardly as promising sign of future success in science.
0:08:49 > 0:08:53But if you have to say one thing about Bateson, he is tenacious.
0:08:53 > 0:08:59He has an unshakeable belief that he is on the verge of discovering something of huge importance.
0:09:02 > 0:09:07Wherever Bateson goes, the whiff of animal droppings soon follows.
0:09:07 > 0:09:11Ever since a colleague gave him a copy of Mendel's paper,
0:09:11 > 0:09:15Bateson's been hooked on inheritance.
0:09:18 > 0:09:23He wants to know if the patterns of inheritance Mendel got in peas
0:09:23 > 0:09:29are the result of a set of universal laws across the whole of the living world.
0:09:29 > 0:09:31And that includes plants.
0:09:33 > 0:09:38His plan is to crossbreed all kinds of different animals
0:09:38 > 0:09:42and to do the same for plants, a hugely laborious task.
0:09:43 > 0:09:47Without a team of helpers and no budget to pay for one,
0:09:47 > 0:09:49it will be impossible.
0:09:51 > 0:09:57But Bateson sees an opportunity to tap into an underused workforce on his doorstep...
0:09:57 > 0:10:01the students of Cambridge's Newnham College.
0:10:02 > 0:10:05They are the perfect workforce,
0:10:05 > 0:10:10fiercely intelligent, unemployed and they're all female.
0:10:10 > 0:10:14They become known as Bateson's ladies.
0:10:15 > 0:10:17Bateson and the ladies get cracking,
0:10:17 > 0:10:21and they start by looking for patterns of inheritance in chickens.
0:10:25 > 0:10:28So this is the sort of experiment they do.
0:10:28 > 0:10:32They cross a black cockerel and a black hen and get a brood of chicks.
0:10:33 > 0:10:39But what intrigues them, surprises them, is that not all of the chicks are black.
0:10:39 > 0:10:41Some of them are white.
0:10:44 > 0:10:48And the more times they repeat the experiment, the stranger it gets.
0:10:48 > 0:10:55The ratio of black to white is always 3-1.
0:10:55 > 0:10:57Every time.
0:11:00 > 0:11:03The parents must have passed down some instruction
0:11:03 > 0:11:07to cause this chick to be white and these ones to be black.
0:11:09 > 0:11:14Those elusive instructions we now know as genes.
0:11:16 > 0:11:21Genes are too small to be seen with the technology Bateson and his ladies had in their day.
0:11:23 > 0:11:26Genetics was a different kind of science.
0:11:27 > 0:11:32Bateson and his ladies used crossbreeding experiments and logic
0:11:32 > 0:11:36to make sense of the three-black-to-one-white ratio in their chickens.
0:11:40 > 0:11:43So, how can you get this 3-1 ratio?
0:11:43 > 0:11:47Well, we know that both of the parents contain the information for black feathers
0:11:47 > 0:11:49because they are both black.
0:11:49 > 0:11:54But we also know that somewhere hidden inside them there is information for white feathers,
0:11:54 > 0:11:58because between them they can produce a white bird.
0:11:58 > 0:12:04So there must be at least two sets of information in each parent for feather colour,
0:12:04 > 0:12:07one black and one white.
0:12:08 > 0:12:13So Bateson tries to work out how those two pieces of information
0:12:13 > 0:12:17could lead to the 3-1 ratio, and this is how he did it.
0:12:18 > 0:12:22Imagine that a chick gets information for black feathers from its father
0:12:22 > 0:12:25and information for black feathers from its mother.
0:12:25 > 0:12:28Or it could inherit black from dad and white from mum,
0:12:28 > 0:12:32or white from dad and black from mum.
0:12:32 > 0:12:38Or, finally, it could get information for white feathers from both of them.
0:12:39 > 0:12:44Bateson and his team observe that breeding from a pair of black chickens
0:12:44 > 0:12:47always produces three black chicks for every white chick.
0:12:48 > 0:12:54To explain that observation, he has to make one final logical assumption.
0:12:56 > 0:13:01Bateson deduces that the information for black feathers overrides the information for white,
0:13:01 > 0:13:05so in three of the chicks you get black feathers.
0:13:05 > 0:13:09One...two...three.
0:13:10 > 0:13:14Only when the chick gets information for white feathers from both of its parents
0:13:14 > 0:13:19and no instructions for black feathers do you get a white chick.
0:13:19 > 0:13:25And bingo! You have your 3-1, three black, one white ratio.
0:13:26 > 0:13:32If Bateson's explanation works for chickens, what about other animals?
0:13:34 > 0:13:36And why stop there?
0:13:36 > 0:13:41He knows that it holds true for peas, but what about other plants?
0:13:41 > 0:13:46Perhaps every living thing is governed by the same laws of inheritance.
0:13:46 > 0:13:51To find out, he'll need to look beyond his chickens.
0:13:57 > 0:14:05Bateson and his ladies breed pigeons, goats, guinea pigs, rabbits, mice...
0:14:06 > 0:14:11Wherever they look, they find the same inheritance patterns they found with their chickens,
0:14:11 > 0:14:15the same that Mendel found with his peas.
0:14:18 > 0:14:23Everywhere, in every species, the patterns are confirmed.
0:14:23 > 0:14:28And Bateson is blown away because he believes he has found the key
0:14:28 > 0:14:36to the mechanism by which all living creatures inherit the features that make them them.
0:14:36 > 0:14:40And the only way the ratios can be explained
0:14:40 > 0:14:45is if those features are passed down from generation to generation
0:14:45 > 0:14:48in discrete units of inheritance.
0:14:50 > 0:14:52A new science is born.
0:14:52 > 0:14:56Bateson gives it the name by which we now know it...
0:14:56 > 0:14:58genetics.
0:15:00 > 0:15:04In a matter of years, Bateson has turned from marginal eccentric
0:15:04 > 0:15:07into international scientific superstar.
0:15:10 > 0:15:15He has proved that the strange numbers Mendel first saw in peas
0:15:15 > 0:15:19are the result of a set of universal genetic laws.
0:15:25 > 0:15:29These laws explain how animal and plant characteristics
0:15:29 > 0:15:32are inherited in past generations,
0:15:32 > 0:15:39and the same laws can now be used to predict how they will be inherited in future generations of plants.
0:15:49 > 0:15:53But in 1903, Bateson hits a problem.
0:15:56 > 0:15:59There's a plant lurking at the back of his laboratory
0:15:59 > 0:16:02that doesn't seem to be playing according to the rules.
0:16:02 > 0:16:06It seems to defy everything Bateson has learned about genetics.
0:16:06 > 0:16:08The plant is snapdragon
0:16:08 > 0:16:11and the problem is the colour of its flowers.
0:16:21 > 0:16:23From one generation to the next,
0:16:23 > 0:16:28the inheritance of colours seems utterly unpredictable.
0:16:28 > 0:16:31New colours seem to come out of nowhere.
0:16:31 > 0:16:33Yellow...
0:16:33 > 0:16:35crimson...
0:16:36 > 0:16:37..magenta.
0:16:39 > 0:16:45Bateson has to question if the laws of genetics have reached their limit with snapdragons.
0:16:46 > 0:16:51So he puts one of the brightest geneticists in his female team on the case...
0:16:53 > 0:16:55..Muriel Wheldale.
0:16:56 > 0:17:01Wheldale has an uncommon gift for making sense of complex patterns.
0:17:02 > 0:17:05And she loves snapdragons.
0:17:07 > 0:17:13Wheldale sets about her task armed with state-of-the-art genetic technology...
0:17:13 > 0:17:17pencil, paper and lots of patience.
0:17:19 > 0:17:22Wheldale has to do crossbreeding experiments just like Mendel.
0:17:24 > 0:17:27Wheldale takes the pollen from one type of flower
0:17:27 > 0:17:32and crossbreeds it with another plant by dabbing the pollen on its flowers...
0:17:33 > 0:17:36..and grows new plants from the seed.
0:17:39 > 0:17:43Then she has to count the number of flowers of each colour that come up.
0:17:45 > 0:17:47Then repeat...hundreds of times
0:17:47 > 0:17:49with hundreds of plants.
0:17:52 > 0:17:55It looks mind-numbing and it is mind-numbing!
0:17:55 > 0:18:00And this period of genetic research was called "the bean-counting period".
0:18:00 > 0:18:04The trick was to remain focused on solving the problem.
0:18:09 > 0:18:14For four years Wheldale sows and grows and counts...
0:18:14 > 0:18:18until finally she makes a breakthrough.
0:18:19 > 0:18:26Wheldale works out that there are several genes that influence the colour of snapdragon flowers.
0:18:27 > 0:18:32Every possible combination of those genes generates its own unique colour.
0:18:35 > 0:18:37It's a simple secret code,
0:18:37 > 0:18:40and Wheldale has cracked it.
0:18:45 > 0:18:49Now she can predict the inheritance of these colours...
0:18:51 > 0:18:53..just like anything else in nature.
0:18:57 > 0:19:01The colours of snapdragon flowers may seem trivial and whimsical,
0:19:01 > 0:19:06but they reveal something fundamental to all of life on earth.
0:19:06 > 0:19:09And the truth is perhaps shocking,
0:19:09 > 0:19:16that the amazing biological diversity that we see around us does not require a supernatural explanation.
0:19:16 > 0:19:22It is the result of genes working together like the components of a beautiful machine.
0:19:27 > 0:19:32Bateson showed that Mendel's laws of inheritance were true.
0:19:32 > 0:19:39Wheldale proved that genetics could predict the inheritance of even the most complex features.
0:19:44 > 0:19:50By 1913, botanists see genes as a car-assembly line.
0:19:50 > 0:19:57Genes are the components of machines, ready to be assembled and exploited by crossbreeding.
0:20:10 > 0:20:15Out of the First World War comes a new generation of botanists
0:20:15 > 0:20:18who can see that the future of genetics will change the world.
0:20:22 > 0:20:27They want to put genetics to practical use.
0:20:36 > 0:20:42A 29-year-old Ukrainian called Nikolai Vavilov is lucky to be alive.
0:20:43 > 0:20:48He has narrowly avoided falling to his death in the mountains of Central Asia.
0:20:53 > 0:20:55As far as Vavilov's concerned,
0:20:55 > 0:20:59what's at stake is well worth the risk.
0:21:06 > 0:21:11He's the first botanist to understand the true potential of genetics
0:21:11 > 0:21:14to revolutionise agriculture.
0:21:20 > 0:21:23Nikolai Vavilov is a plant breeder.
0:21:23 > 0:21:28He is just back from an expedition collecting plants with valuable attributes.
0:21:28 > 0:21:32He wants to cross them to create a new generation of crops.
0:21:32 > 0:21:35This is more than a passion for Vavilov.
0:21:35 > 0:21:38The fate of the nation is at stake
0:21:38 > 0:21:42and he believes that plant genetics can save the Soviet Union.
0:21:46 > 0:21:51The Russian Revolution has left agriculture in chaos.
0:21:51 > 0:21:55The new Soviet Union is unable to feed itself.
0:21:58 > 0:22:02Nikolai Vavilov learned genetics in Europe.
0:22:04 > 0:22:08Many evenings spent deep in discussion with William Bateson in Cambridge
0:22:08 > 0:22:11have sparked Vavilov's imagination.
0:22:13 > 0:22:16Vavilov's plan is to crossbreed the plants he collects
0:22:16 > 0:22:20to create new combinations of characteristics,
0:22:20 > 0:22:22super crops for the Soviet Union.
0:22:24 > 0:22:29Vavilov thinks that he can create a revolutionary set of new crops,
0:22:29 > 0:22:32assembling them using the best components,
0:22:32 > 0:22:34like cars on a production line.
0:22:34 > 0:22:38And the expedition from which he has just returned is the start.
0:22:38 > 0:22:42Imagine being able to create a fruit tree that can fight every disease
0:22:42 > 0:22:46or a super wheat that combines the yield of wheat from the plains
0:22:46 > 0:22:49and the cold tolerance of wheat from the mountains.
0:22:54 > 0:23:00Vavilov realises that plants with valuable properties will not all be found in Russia.
0:23:12 > 0:23:15To crossbreed his new generation of crops,
0:23:15 > 0:23:20Vavilov will need to combine varieties collected from right across the globe.
0:23:23 > 0:23:30Little by little, he gathers the seeds of every plant he finds in a central vault.
0:23:33 > 0:23:37He's the pioneer of worldwide seed banks.
0:23:41 > 0:23:44A seed is a survival capsule.
0:23:44 > 0:23:51It contains not only the embryonic plant, but also a food supply and a tough outer coat.
0:23:51 > 0:23:55It could almost have been designed for the storage of genes.
0:23:56 > 0:24:01Vavilov was a pioneer in the movement to use seeds
0:24:01 > 0:24:06as a way of preserving our biological inheritance
0:24:06 > 0:24:09for generations to come.
0:24:09 > 0:24:13And there is now a worldwide movement of seed banks
0:24:13 > 0:24:17conserving not only our varieties that we have already,
0:24:17 > 0:24:23but also the wild relatives of the crops that we shall need in the future
0:24:23 > 0:24:28to make plants to produce more and more food in different conditions.
0:24:34 > 0:24:40Vavilov's worldwide seed bank is the first step in his bold strategy
0:24:40 > 0:24:43to create super crops for the USSR.
0:24:46 > 0:24:49Lenin buys into Vavilov's vision
0:24:49 > 0:24:54and puts him in charge of the most influential agricultural bodies in the Soviet Union.
0:25:01 > 0:25:06Vavilov is to be responsible for a new scientific approach to breeding crops.
0:25:12 > 0:25:16Until now it has taken centuries to breed plants with useful features,
0:25:16 > 0:25:21but, armed with the new understanding of genetics, Vavilov can work much faster.
0:25:25 > 0:25:30But even by Vavilov's most optimistic estimates, the work will take years.
0:25:31 > 0:25:34He was often heard to say, "Life is short. We must hurry."
0:25:35 > 0:25:38He couldn't possibly have known how right he was.
0:25:48 > 0:25:54By 1929, the USSR is under the control of Joseph Stalin.
0:25:56 > 0:25:59Stalin doesn't understand science.
0:25:59 > 0:26:03He has no patience for the likes of Vavilov.
0:26:04 > 0:26:11He insists the USSR needs methods to increase crop yields that make a difference tomorrow,
0:26:11 > 0:26:14not in ten years' time.
0:26:17 > 0:26:21Stalin's men say genes do not exist.
0:26:21 > 0:26:25Only the environment in which a plant grows up is important.
0:26:26 > 0:26:29It fits Marxist ideology beautifully.
0:26:29 > 0:26:32Breeding and birthright count for nothing.
0:26:32 > 0:26:37Genetics, they say, is bourgeois Western propaganda,
0:26:37 > 0:26:44and slowly Soviet geneticists realise that their science is a political liability.
0:26:58 > 0:27:01These are dangerous times.
0:27:02 > 0:27:09At the age of 45, Vavilov has invested decades in his great genetic project.
0:27:10 > 0:27:12Then disaster strikes.
0:27:12 > 0:27:16A series of catastrophic harvests hits the USSR.
0:27:16 > 0:27:19Stalin is looking for a scapegoat.
0:27:19 > 0:27:24Vavilov runs several agricultural institutions. He's the perfect target.
0:27:30 > 0:27:34A summer evening in the Carpathian Mountains of Ukraine.
0:27:35 > 0:27:38Vavilov collects plants.
0:27:39 > 0:27:42On this occasion, though, he is not alone.
0:27:56 > 0:28:00Four men disguised as local bureaucrats
0:28:00 > 0:28:03have searched for him all day.
0:28:05 > 0:28:08They are Stalin's secret police.
0:28:15 > 0:28:19These are Nikolai Vavilov's last moments of freedom.
0:28:27 > 0:28:30On 26 January 1943,
0:28:30 > 0:28:33Vavilov dies on the floor of a prison cell.
0:28:33 > 0:28:37The man who has devoted his life to feeding the Soviet Union
0:28:37 > 0:28:41succumbs finally to, of all things, starvation,
0:28:41 > 0:28:45and genetics in the Soviet Union is put back decades.
0:29:04 > 0:29:10World events now threaten to wipe out Vavilov's global work to develop genetics.
0:29:18 > 0:29:20The Second World War...
0:29:20 > 0:29:23it's the siege of Leningrad.
0:29:26 > 0:29:3012 Russian scientists who have worked with Vavilov
0:29:30 > 0:29:34have been trapped in an underground vault for the last three months.
0:29:37 > 0:29:40German artillery is pummelling the street outside,
0:29:40 > 0:29:43yet the scientists trapped inside the vault
0:29:43 > 0:29:47believe they are protecting the Soviet Union's greatest treasure.
0:29:51 > 0:29:54They are guarding Vavilov's seed bank,
0:29:54 > 0:29:58a vast collection of seeds from around the world,
0:29:58 > 0:30:03brought together to crossbreed crops for the future of all humankind.
0:30:11 > 0:30:17If the war destroys this collection, his life's work will have been in vain.
0:30:22 > 0:30:28It's almost impossible to imagine what it must have been like for those scientists trapped in that basement,
0:30:28 > 0:30:33because not only was there a battle raging above them with the enemy trying to kill them,
0:30:33 > 0:30:39but they were faced with the horrendous dilemma that they had no food.
0:30:39 > 0:30:41They were desperately hungry,
0:30:41 > 0:30:45yet they were surrounded by edible seeds...
0:30:45 > 0:30:47which they did not touch.
0:30:47 > 0:30:50The seed bank remained intact.
0:30:50 > 0:30:56And these scientists sacrificed themselves to preserve a genetic resource
0:30:56 > 0:31:00that we can all benefit from in future years.
0:31:14 > 0:31:20Mendel, Bateson and Wheldale first unveiled the universal laws of genetics
0:31:20 > 0:31:23that govern all plant characteristics.
0:31:29 > 0:31:32Vavilov tried to put those laws to use,
0:31:32 > 0:31:36to combine the properties of plants from around the globe.
0:31:37 > 0:31:41He thought he would trigger a revolution in agriculture.
0:31:45 > 0:31:50But Vavilov was stopped before he could see his dream realised.
0:31:58 > 0:32:03The global revolution in food production would fall to someone else.
0:32:14 > 0:32:16One year after Vavilov's death,
0:32:16 > 0:32:19an American plant breeder called Norman Borlaug
0:32:19 > 0:32:25is pacing his fields in a remote research station near Chapingo in Mexico.
0:32:31 > 0:32:34Borlaug is an ex-championship wrestler
0:32:34 > 0:32:39who grew up during the disastrous crop failures of the Midwest Dust Bowl.
0:32:39 > 0:32:45Maybe it was this that fuelled his determination to make agriculture work.
0:32:46 > 0:32:49Now he is a promising young plant breeder,
0:32:49 > 0:32:53specialising in making plants defend themselves against disease.
0:32:53 > 0:32:56And he's brought his knowledge to Mexico.
0:33:02 > 0:33:08Poor soils and fungal disease have held back farming in Mexico for generations.
0:33:11 > 0:33:13Borlaug is no lab geneticist,
0:33:13 > 0:33:16he's a hands-in-the-soil agriculturalist.
0:33:18 > 0:33:22But the advances in plant genetics by Bateson, Vavilov and others
0:33:22 > 0:33:29have given him an understanding of how to combine useful characteristics through crossbreeding.
0:33:30 > 0:33:35Borlaug has managed to crossbreed different varieties of wheat
0:33:35 > 0:33:37to increase disease resistance.
0:33:39 > 0:33:45But his most robust variety doesn't behave quite as he expects.
0:33:47 > 0:33:52Borlaug's plants grow too successfully.
0:33:52 > 0:33:56The heads are beautiful, plump, full of nutrition,
0:33:56 > 0:33:59but the stems are growing like crazy too,
0:33:59 > 0:34:04and they're too tall to support the heavy seed heads.
0:34:04 > 0:34:08So in the slightest gust of wind, they fall over.
0:34:08 > 0:34:11The seeds hit the ground, they rot,
0:34:11 > 0:34:17and that's a waste of time, effort and food.
0:34:21 > 0:34:25The solution to Borlaug's falling wheat comes out of the Second World War.
0:34:27 > 0:34:29Japan is defeated by the Allies.
0:34:29 > 0:34:33American troops spread across the country.
0:34:35 > 0:34:39The occupied territory is a new resource to be exploited.
0:34:45 > 0:34:47Like Vavilov before them,
0:34:47 > 0:34:53the Americans know that foreign lands hold new plants with unfamiliar properties.
0:34:58 > 0:35:00In a corner of Northeast Japan,
0:35:00 > 0:35:07American botanists stumble across a strain of wheat that seems to have adapted to the local climate.
0:35:10 > 0:35:14The discovery of this strain changes Borlaug's fortunes,
0:35:14 > 0:35:18and the fortunes of world food production.
0:35:19 > 0:35:23The strain is later named Norin 10.
0:35:27 > 0:35:30I'm guessing you haven't heard of Norin 10,
0:35:30 > 0:35:36and compared to the other wheat growing around the world at the time of its discovery,
0:35:36 > 0:35:41it wasn't much different, apart from the fact that it grew to half the height.
0:35:42 > 0:35:45Now dwarf wheat may not sound very revolutionary,
0:35:45 > 0:35:52but it was about to trigger the most seismic social change in modern times.
0:35:54 > 0:35:58Norin 10 is a natural genetic aberration.
0:35:59 > 0:36:01It is a mutation.
0:36:02 > 0:36:09In 1953, Borlaug sees a practical application for the insights of Bateson and Vavilov,
0:36:09 > 0:36:13a way to use Norin 10 to produce a new plant
0:36:13 > 0:36:16with just the characteristics he needs.
0:36:17 > 0:36:20Borlaug crosses his top-heavy Mexican variety
0:36:20 > 0:36:23with the stumpy Japanese variety...
0:36:23 > 0:36:30and creates a short plant with nutritious seed heads.
0:36:30 > 0:36:32Let's see what the advantage of that was.
0:36:34 > 0:36:39If this weight simulates a gust of wind,
0:36:39 > 0:36:42then if we hang it on this tall plant...
0:36:43 > 0:36:46Ah! Broken.
0:36:47 > 0:36:49On the other hand...
0:36:50 > 0:36:55..if we hang the same weight on the short plant...
0:36:58 > 0:37:01..the stem doesn't break and the plant doesn't fall over.
0:37:03 > 0:37:05Small change for a plant,
0:37:05 > 0:37:07giant leap for mankind.
0:37:29 > 0:37:32Borlaug's wheat sweeps across the world.
0:37:34 > 0:37:39In 1966, he takes it to the Indian subcontinent.
0:37:43 > 0:37:47Since the successful introduction of dwarf wheat,
0:37:47 > 0:37:51India has not once experienced a national famine.
0:37:53 > 0:37:58Borlaug's extraordinary success is given the name...
0:37:58 > 0:38:01the green revolution.
0:38:04 > 0:38:07The increased yields come at a cost.
0:38:07 > 0:38:11Higher inputs of fertiliser and water,
0:38:11 > 0:38:14some people say it's not sustainable for ever...
0:38:14 > 0:38:22but it is clear that this dwarf wheat is the most important plant mutation in the history of civilisation,
0:38:22 > 0:38:29because, armed with it, Norman Borlaug took 1,000 million people out of starvation.
0:38:30 > 0:38:35In 1970, Borlaug was awarded the Nobel Peace Prize.
0:38:37 > 0:38:43His work showed the immense impact of plant genetics on humanity's ability to produce food.
0:38:50 > 0:38:54But like Bateson, Wheldale and Vavilov before him,
0:38:54 > 0:39:00Borlaug relied on endless crossbreeding and observation to create his new hybrids.
0:39:03 > 0:39:07And there was an even more fundamental limitation...
0:39:08 > 0:39:14..Borlaug's success with dwarf wheat was down to the exploitation of a useful mutation
0:39:14 > 0:39:16that had occurred by chance.
0:39:19 > 0:39:24In the end, the green revolution came down to nature's lucky mistake.
0:39:29 > 0:39:32Plant breeders faced one big problem.
0:39:32 > 0:39:37They had to rely on nature to provide them with the raw materials,
0:39:37 > 0:39:41that one-in-a-million useful mutation that they could exploit.
0:39:41 > 0:39:44What if they could cut out nature
0:39:44 > 0:39:48and design, engineer the plant they wanted,
0:39:48 > 0:39:52one that could survive in a hostile environment or resist a disease?
0:39:52 > 0:39:56This is a monumental task,
0:39:56 > 0:40:01because to do it they have to control the genes.
0:40:03 > 0:40:09The botanists' Holy Grail was a new generation of crops made to order.
0:40:09 > 0:40:14Crop breeders needed precision control over plant genes.
0:40:17 > 0:40:20A decade after the green revolution,
0:40:20 > 0:40:25that control of genes remained as elusive as it had always been.
0:40:32 > 0:40:36What comes to mind if I say "sweetcorn"?
0:40:37 > 0:40:43Is it ranks of identical, pale, yellow seeds,
0:40:43 > 0:40:46like the ones you buy at the greengrocer?
0:40:47 > 0:40:50Now, this is wild corn.
0:40:51 > 0:40:54And this is amazing!
0:40:54 > 0:40:57This is really, really different.
0:40:58 > 0:41:00This looks random.
0:41:00 > 0:41:04Look at that! Completely different again.
0:41:05 > 0:41:10Almost flame-coloured, looks like it's been burnt almost, it's been cooked already.
0:41:10 > 0:41:13It almost looks wrong.
0:41:15 > 0:41:18Every one of these is different.
0:41:21 > 0:41:26This one's almost getting towards some of the seeds that we get in corn on the cob.
0:41:26 > 0:41:30This one, you just would never see in the greengrocer's.
0:41:30 > 0:41:35These ones, different again. I've no idea what's inside this one.
0:41:38 > 0:41:41It really is worse than pass the parcel.
0:41:42 > 0:41:45And there we've got... we've got purple, we've got blue,
0:41:45 > 0:41:47we've got dark purple...
0:41:49 > 0:41:53Now, 50 years ago, these crazy patterns in corn
0:41:53 > 0:41:57set in motion a whole new way of thinking about genetics.
0:42:07 > 0:42:12In 1945, tucked away in a corner of Long Island, New York,
0:42:12 > 0:42:18you would have found a field of maize that at first glance looks ordinary.
0:42:20 > 0:42:26This is the stomping ground of a brilliant botanist who would reveal the inner workings of genes,
0:42:26 > 0:42:32and so propel plant genetics into the modern age.
0:42:36 > 0:42:39Pacing up and down the rows of plants, cigarette in holder,
0:42:39 > 0:42:43is a woman with the kind of biceps you only get from digging.
0:42:43 > 0:42:46She trusts nobody else to look after her maize plants,
0:42:46 > 0:42:49so she does all of the farm work herself.
0:42:50 > 0:42:52She's not a farmer.
0:42:52 > 0:42:55Her maize is not there to feed anyone.
0:42:58 > 0:43:02She's a geneticist. Her name is Barbara McClintock.
0:43:05 > 0:43:07McClintock is obsessed with understanding
0:43:07 > 0:43:11how plants pass their characteristics down to the next generation...
0:43:14 > 0:43:17..the same question that fascinated Mendel, Bateson and Wheldale.
0:43:20 > 0:43:27McClintock has noticed mutations in her maize that behave in totally unexpected ways.
0:43:28 > 0:43:31SHOTS RING OUT
0:43:35 > 0:43:39McClintock's only employee is a human scarecrow
0:43:39 > 0:43:43in the fields to shoot any birds that threaten her plants,
0:43:43 > 0:43:46because she cannot afford to lose a single one.
0:43:46 > 0:43:49Each is a rare, one-in-a-billion chance mutation.
0:43:49 > 0:43:56She suspects that her maize is the key to something really odd going on in plants.
0:44:00 > 0:44:05McClintock is captivated by one strange mutation in particular.
0:44:08 > 0:44:10This pattern on the seeds.
0:44:10 > 0:44:16It makes her suspect she might need to rewrite the rules of genetics.
0:44:21 > 0:44:24Day after day, through the seasons,
0:44:24 > 0:44:28she puts transparent bags over the female parts of the maize
0:44:28 > 0:44:30to stop them being pollinated by the wrong plant.
0:44:30 > 0:44:36She puts paper bags over the male parts from other plants to collect their pollen.
0:44:38 > 0:44:42McClintock does this again and again on hundreds of plants.
0:44:46 > 0:44:51Then, at the end of the day, when the male parts have shed their pollen,
0:44:51 > 0:44:58she takes the paper bag and taps out the pollen on to the female parts of the plants she's protected.
0:45:03 > 0:45:06McClintock places a wooden paddle in the ground
0:45:06 > 0:45:09to remind her which plant was crossed with which.
0:45:09 > 0:45:15She then writes down the information on an index card which she takes back to the lab.
0:45:15 > 0:45:20On too many of the cards, she's forced to write, "Pulled up by the birds".
0:45:20 > 0:45:23That guy with the gun couldn't have been a very good shot.
0:45:23 > 0:45:30And that must have been heartbreaking because each one of McClintock's maize plants is a unique experiment.
0:45:31 > 0:45:33Maize in the wild is normally red.
0:45:35 > 0:45:38Today the sweetcorn in shops is yellow
0:45:38 > 0:45:41because of crossbreeding a mutation in that gene.
0:45:42 > 0:45:47But in McClintock's mutant maize, the red colour comes back.
0:45:54 > 0:45:58Geneticists at the time think they understand mutations...
0:45:58 > 0:46:00it all seems pretty simple.
0:46:00 > 0:46:05When a gene is working as it should, it's like a light shining,
0:46:05 > 0:46:12but when a mutation occurs, and the gene stops working, the light goes out.
0:46:13 > 0:46:15There may be any number of explanations for this.
0:46:15 > 0:46:17Maybe the filament has blown...
0:46:18 > 0:46:20Or the bulb is cracked.
0:46:20 > 0:46:21SMASH!
0:46:21 > 0:46:22Or the wiring's faulty.
0:46:22 > 0:46:27But whatever the reason, the important thing is, they believe,
0:46:27 > 0:46:30the light can never go back on.
0:46:31 > 0:46:35But McClintock's maize mutation is different,
0:46:35 > 0:46:41because in many of her plants it seems to revert spontaneously back to normal.
0:46:42 > 0:46:47A mutation reverting back to normal should be impossible,
0:46:47 > 0:46:50like a broken light bulb suddenly coming back on.
0:46:52 > 0:46:55So she needs to isolate the mutation,
0:46:55 > 0:46:58a procedure she's done a thousand times before.
0:46:58 > 0:47:01It should not be hard. But this time it's different
0:47:01 > 0:47:05because the mutation seems to be in two places at the same time.
0:47:05 > 0:47:07And that should be impossible.
0:47:07 > 0:47:14She is baffled. And her interest in the mutation begins to become obsessional.
0:47:15 > 0:47:20That winter, after thousands of crossbreeding experiments,
0:47:20 > 0:47:24all that counting, McClintock must have been exhausted.
0:47:24 > 0:47:29But still her mutation makes no sense to her.
0:47:30 > 0:47:33If it had been me, I'd have gone over the edge.
0:47:35 > 0:47:38The frustration eventually gets to McClintock.
0:47:38 > 0:47:40She has a minor breakdown.
0:47:41 > 0:47:44Then, one evening, after three years of work,
0:47:44 > 0:47:48it all begins to make sense.
0:47:50 > 0:47:53McClintock finally understands what is going on.
0:47:54 > 0:47:57Like the early geneticists before her,
0:47:57 > 0:48:01McClintock cannot see what is happening to the genes in her maize.
0:48:01 > 0:48:05What she discovers is a feat of logic.
0:48:07 > 0:48:14McClintock deduces that her mutation can be turned on and off,
0:48:14 > 0:48:20that its appearance must be controlled by some kind of switch.
0:48:21 > 0:48:23Mutations that switch on and off.
0:48:26 > 0:48:31McClintock showed that genes are part of a dynamic, shifting system,
0:48:31 > 0:48:36and, most importantly, that genes are under the control of switches.
0:48:39 > 0:48:43McClintock's vision was revolutionary.
0:48:46 > 0:48:47Bateson,
0:48:47 > 0:48:49Wheldale,
0:48:49 > 0:48:50Vavilov,
0:48:50 > 0:48:52Borlaug...
0:48:52 > 0:48:59before McClintock geneticists thought that genes were passed passively from generation to generation.
0:49:03 > 0:49:07McClintock blew that idea out of the water.
0:49:13 > 0:49:19She saw that plants could switch their genes on or off when needed...
0:49:20 > 0:49:23..a mechanism for plants to fine-tune their behaviour
0:49:23 > 0:49:25to survive everything the world throws at them.
0:49:35 > 0:49:40A new level on which genes work in the world of plants.
0:49:49 > 0:49:56And yet, for 20 years, geneticists resisted McClintock's work as being outlandish.
0:49:56 > 0:50:04The discovery of DNA structure in 1953 and proof of gene switches in 1961,
0:50:04 > 0:50:10would give botanists new tools to control the gene switches McClintock revealed.
0:50:13 > 0:50:19I've watched as that DNA technology has transformed plant science during my career.
0:50:24 > 0:50:28Geneticists have isolated thousands of different genes.
0:50:28 > 0:50:31They can turn genes on and off
0:50:31 > 0:50:34and move them between organisms.
0:50:36 > 0:50:40Most of us know this as genetic modification, GM.
0:50:42 > 0:50:49Genetic modification is loaded with prejudice and misinformation,
0:50:49 > 0:50:57so it's very easy to forget how it fits into the story of genetics and agriculture
0:50:57 > 0:50:59and civilisation.
0:51:00 > 0:51:04For 10,000 years, we have been creating new plants
0:51:04 > 0:51:07by putting pollen where pollen should never go
0:51:07 > 0:51:11and by selecting and preserving mutations.
0:51:11 > 0:51:19And as a result of the efficient way that we grow our crops in large monocultures,
0:51:19 > 0:51:25these plants are susceptible to pests and diseases.
0:51:25 > 0:51:29Now, if we can build stronger, more efficient plants,
0:51:29 > 0:51:32then they will be able to fight off those pests and diseases,
0:51:32 > 0:51:35and their yield will go up.
0:51:36 > 0:51:40Certainly there may be risks attached to genetically modified plants,
0:51:40 > 0:51:43but it is a known risk
0:51:43 > 0:51:49that people are dying of starvation because we cannot produce enough food.
0:51:49 > 0:51:53And that situation is not going to improve as population grows.
0:51:55 > 0:52:00So far I believe GM has failed to address mass hunger.
0:52:03 > 0:52:05But that may be about to change.
0:52:07 > 0:52:12A global consortium of labs has launched has launched one of the most ambitious attempts ever
0:52:12 > 0:52:14to tackle world hunger.
0:52:15 > 0:52:21Jane Langdale at the Plant Sciences labs in Oxford runs one of the teams.
0:52:23 > 0:52:27Her aim is to revolutionise the productivity of rice.
0:52:29 > 0:52:32So, Jane, why is rice important?
0:52:32 > 0:52:34Rice is an incredibly important crop.
0:52:34 > 0:52:3690% of the rice that is grown in the world
0:52:36 > 0:52:40- is eaten by the people who grow it. - By the farmers?- Yes.
0:52:40 > 0:52:44They use it directly for food. They don't feed it to animals, they don't use any of it for heating
0:52:44 > 0:52:46or anything. They actually eat it.
0:52:46 > 0:52:51Right now, you can grow a hectare of rice and you will feed 27 people.
0:52:51 > 0:52:56- OK.- By 2050, you've got to feed 43 people from that same land area,
0:52:56 > 0:52:59and you've got to use less fertiliser,
0:52:59 > 0:53:03there'll be less predictable rainfall and water
0:53:03 > 0:53:08- and probably there'll be increasing competition to use that land for something else.- Yeah.
0:53:08 > 0:53:10So it's a big problem.
0:53:13 > 0:53:21For the last 40 years, rice production has kept pace with the increase in population.
0:53:21 > 0:53:27But we have reached the limit of how much can be achieved with existing farmland and fertiliser.
0:53:28 > 0:53:33A radical new strategy is needed if billions are to survive.
0:53:37 > 0:53:42Jane Langdale wants to change the way rice does photosynthesis.
0:53:44 > 0:53:49Like all plants, it uses sunlight, carbon dioxide and water to make sugar.
0:53:50 > 0:53:55But rice does this very inefficiently in hot, dry climates.
0:53:55 > 0:54:00Langdale hopes to redesign rice to make it as efficient as maize.
0:54:02 > 0:54:06To me, the leaves of maize and rice look pretty similar,
0:54:06 > 0:54:10so how difficult can it be to make rice more like maize?
0:54:10 > 0:54:13If we are to achieve our goal
0:54:13 > 0:54:15of converting rice into maize-type photosynthesis,
0:54:15 > 0:54:21then we've got to completely change the internal architecture of this leaf to look like this one.
0:54:21 > 0:54:25We've got to completely change the biochemistry. It's not trivial.
0:54:26 > 0:54:35Photosynthesis in maize depends on those cells that surround the many veins inside their leaves.
0:54:36 > 0:54:39OK, so if we just focus this a little bit...
0:54:39 > 0:54:42and then I can show you on the screen here,
0:54:42 > 0:54:45and you can see that the veins are stained pink,
0:54:45 > 0:54:50you can see that there's two large veins there and there's about 20 cells in between the two.
0:54:50 > 0:54:53Whereas, if we look at the regular leaf above, you can see a major vein here,
0:54:53 > 0:54:59but then you can count one, two, three, four, five veins in the same gap as there is with that one.
0:54:59 > 0:55:04So this is essentially what the rice leaf looks like, and we need to make it look like this.
0:55:04 > 0:55:07We need these more regular veins,
0:55:07 > 0:55:09because unless that pattern is there in the leaf,
0:55:09 > 0:55:14then the rice leaf will not be able to photosynthesise like maize.
0:55:18 > 0:55:23Langdale's team is trying to unpick the sequence of gene switches
0:55:23 > 0:55:27that allows maize to make more veins in its leaves.
0:55:31 > 0:55:35The switches are flipped in the very early stages of life,
0:55:35 > 0:55:44so the only way to study the process is by teasing out tiny patches of growing cells, buried in the stems.
0:55:49 > 0:55:51It's delicate, skilled work.
0:56:00 > 0:56:03So I'm bewildered that Jane's asked me to give it a go!
0:56:03 > 0:56:07- Pull it out.- Pull it out? OK. There we go. Right.
0:56:07 > 0:56:09So we've got our young plant, so...
0:56:09 > 0:56:12- Right, so if you just put it on the...- I'm looking for something inside there?
0:56:12 > 0:56:15- Inside there, yes.- How big is it?
0:56:15 > 0:56:17Ish? You know, to the nearest millimetre?
0:56:17 > 0:56:20- To the nearest millimetre? It's not even close to a millimetre!- OK!
0:56:23 > 0:56:25How am I going to recognise it when I see it?
0:56:25 > 0:56:27I'm going to tell you it's there.
0:56:29 > 0:56:34- Now, be careful.- Yeah. - If you make a big cut like that... - I'm being incredibly careful.
0:56:34 > 0:56:37..you might go straight through the main shoot.
0:56:40 > 0:56:44- It's very much like cutting up an onion, isn't it, for tea?- No.
0:56:46 > 0:56:49- Careful.- I am being careful.
0:56:50 > 0:56:54- Is it in there?- Wait, stop! Stop, stop, stop!
0:56:54 > 0:56:56Increase the magnification if you can.
0:57:01 > 0:57:02- Is that it?- No.
0:57:02 > 0:57:07- Is it further in still?- Believe me, I'll scream if you get to it.
0:57:09 > 0:57:11Uh-huh...!
0:57:13 > 0:57:14Oh!
0:57:14 > 0:57:18I hate to say this, but I think you just lost it.
0:57:18 > 0:57:19Oh!
0:57:19 > 0:57:21- Is it that?- Yeah.
0:57:22 > 0:57:25Is that it, the middle one that I've just gone through there?
0:57:25 > 0:57:27- Yeah.- Oh, sod it!
0:57:28 > 0:57:37For a single experiment, Langdale's team needs to dissect 500 tiny balls of cells
0:57:37 > 0:57:41of the kind I took two hours to turn into a mush.
0:57:42 > 0:57:46Each phase of this project seems to me monumental.
0:57:52 > 0:57:56The first green revolution used plant-breeding techniques
0:57:56 > 0:57:59that we'd been exploiting for thousands of years.
0:57:59 > 0:58:06The next revolution, starting in Jane Langdale's lab and in other labs around the world,
0:58:06 > 0:58:12is exploiting a deeper understanding of genetics.
0:58:12 > 0:58:15And it may be a long shot,
0:58:15 > 0:58:23but the target of feeding 9,000 million people has to make it worthwhile.
0:58:27 > 0:58:31Subtitles by Red Bee Media Ltd
0:58:31 > 0:58:35E-mail subtitling@bbc.co.uk