The Discover Best Practice Farming for a Sustainable 2050 Course is based on a clear vision: imagine best practice farming for 2050, start to implement these strategies now, all the while making sure it will still be profitable. At UWA we're doing just that with the Future Farm 2050 Project, set on a mixed-enterprise farm in Western Australia and we want you to learn how it can be done in your part of the world. Although this course is based on agriculture, it's not only about farming. It is a multi-disciplinary course that addresses a wide range of issues confronting the industry, including rural communities, rural infrastructure and conservation of biodiversity in agriculture. By completing this course you will understand that feeding and clothing the planet requires a multi-disciplinary approach and upon completion you will be able to explain best practices of sustainable farming and apply them in new contexts.
Professor Wallace Cowling: Plant Breeding
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來自 University of Western Australia 的課程
Discover Best Practice Farming for a Sustainable 2050
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從本節課中
Ecological Cropping
Welcome to Week 3 of "Discover Best Practice Farming for a Sustainable 2050". This week you'll be introduced to Ecological Cropping, and more specifically weed management and plant breeding. Effective weed management strategies, in a changing environment with increasing resistance to herbicides, has become increasingly important for crop management. In addition to these management strategies, successful cropping also depends on high yielding varieties, tolerant to a changing environment.
與講師見面
Graeme MartinProfessor
School of Agriculture and Environment
[MUSIC]
Hello, my name is Wallace Cowling and
I'm the professor in plant breeding at the University of Western Australia.
This part of the course on the future of farming in 2050 looks at a new,
green revolution in plant breeding that could change the future of agriculture and
food production.
We rely on our crops to convert the sun's energy into food,
plants can be bred to do this more efficiently.
Today, we will discuss a new approach to plant breeding which will speed up
the process and allow genetic improvements to continue long into the future.
The goal is to breed crops that yield more grain, suffer less disease,
and tolerate stresses better than current crop varieties.
The Food and Agriculture Organization of the United Nations has stated
that we must increase agricultural production by 70% by 2050 with
sustainable use of genetic resources for food and agriculture.
Plant breeding underpins future improvements in crop production.
Today's talk is built on three ideas.
First, traditional plant breeding methods are slow and
they suffer from low genetic diversity which will prevent us from reaching
FAO food production goals by 2050.
Second, a new green revolution is occurring in plant breeding
by stone methods derive from animal breeding.
And third, the new plant breeding methods will help us to improve
sustainability of agriculture while coping with climate change
Plants are incredibly important as the primary food source for humans.
More than 85% of the world's human food calories come from plants.
Threats to crop food production are a threat to the future of humanity.
Future agriculture will depend on crops that can be grown safely and
sustainably without irreversible damage to the environment,
but the environment is changing.
Global temperatures are expected to increase by at least two
degrees Celsius in this century.
The area of land is decreasing.
Now, crops must survive increasing heat stress and
they must yield more grain per hectare to meet increasing demand for food.
This is the challenge to genetically improve our crops, so
they yield more grain per hectare, tolerate heat and other stresses,
resist disease, and supply food for a hungry world safely and
sustainably and with less input of fertilizer and chemicals.
This may sound like a big ask, how can we be sure that
the new green revolution in plant breeding will help us reach these targets?
Currently, genetic improvement of crops is occurring at less than 1% per year.
In fact, yield improvement has stalled in wheat
in southern Australia since 1990, due to the impact of climate change.
Evidence suggests we are approaching a yield plateau with
traditional plant breeding methods, as a result of climate change.
How do we breed grain crops?
Here you can see a picture of a small grain harvester in a wheat breeding
experiment.
Stripping the grain from the plants in a small plot.
The grain from each plot is weighed and
hundreds of these plots make up a weed breeding experiment.
Only the highest yielding varieties process then tested and
they have to have the best grain quality.
Seed of those best varieties is increased and
eventually, the best new varieties are released to farmers.
Breeders use these varieties in crossing to start the next generation of breeding.
And this process may take ten to 12 years from crossing
to commercial release of new varieties.
But plant breeding field trials are an essential component of
crop genetic improvement.
They allow us to measure grain yield in the same environment as farmers
where they grow their crops.
These results help us to breed better varieties for local condition.
The main question today is how can we make plant breeding more efficient and
faster, our peers in animal breeding are racing ahead in genetic terms.
Egg production, milk production, meat production per animal has doubled over
the past 40 to 50 years, and efficiency of feed conversion has improved.
Crop breeders have not kept pace with animal breeders in terms of rate of
genetic improvement.
In traditional grain crop breeding, cycles of selection are relatively slow.
In quantitative genetics terms, this is called generation interval.
The time it takes from crossing of parents in the current cycle
to selection of superior progeny, and
crossing them as new parents to begin the next cycle of selection.
This can take up to eight or ten years in traditional plant breeding.
One process that takes time is self pollination and
no crops die and set self seed every year.
After several years of selfing, progeny become more and more homozygous, and
eventually, become uniform pure lines.
Most plant breeders wait until they have pure lines before they test them for
economic traits such as grain yield.
It is possible to speed this up, for example,
by undertaking several selfing generations very quickly in the laboratory.
All by using a tissue culture procedure called double haploiding.
Even then, the generation interval can take five years by the time
good parents are identified in field experiments and used in crossing.
There is another problem with this traditional
approach to grain crop breeding.
A lot of genetic diversity is lost
during the process of selfing to produce purer lines.
The genetic diversity in a breeding program
is estimated by effective population size.
In most crop breeding programs, the effective population size is low.
We estimate that most crop breeding programs have less than ten percent
of the effective population size found in animal breeding programs.
Low effective population size results in low genetic diversity, and eventually,
we will reach a a yield plateau due to insufficient genetic diversity.
Today, we will talk about a new plant breeding method that increases effective
population size and genetic diversity in crop breeding programs, and
reduces generation interval.
But first, let us turn our attention to selection,
choosing progeny to become parents in the next cycle.
In animal breeding,
a new selection procedure called Optimal Contribution Selection or
OCS has improved a long term genetic gain.
Our group was the first to try this in plant breeding with exciting results.
With OCS, we showed a potential increase in the rate of genetic progress for
grain yield and disease resistance that could help us reach the FAO's goal for
70% increase in food production by 2050.
To make things more complicated, increasing global
temperatures will cause predictable drop in crop yields,
unless we find a process that allows us to breed for
stress tolerance and grain yield simultaneously.
Our group at the University of Western Australia,
with help from colleagues at the University of New England
in New South Wales, are researching ways to improve methods of plant breeding.
Our approach is to breed plants like animals.
We have started using BLUP breeding in plants.
This approach was introduced into animal breeding over forty years ago.
In BLUP breeding animals proven to be better than their ancestors or
peers are used in mating as soon as they are identified.
Data from all relatives and
ancestors are used in the analysis to predict breeding values.
BLUP breeding with information from relatives is known as the animal model
in quantitative genetics and now, we are applying it to self pollinating plant.
So why was this method not applied to crop breeding years ago?
Possibly because pure line testing provides accurate estimates of
genetic value.
But making pure lines takes time, several years, in fact, and
this slows down genetic progress.
It also tends to reduce genetic diversity in crop breeding programs.
BLUP breeding in contrast is designed for
heterozygous animals which cannot be selft.
So we asked the question, can we make faster genetic progress by estimating
BLUP breeding values on heterozygous cross progeny in plants?
We show that BLUP breeding values for grain yield and
disease resistance were very accurate on heterozygous progeny,
and these progeny when tested in field trials with data from relatives,
all of the ancestors and peers were
included in the BLUP analysis just as in animal breeding.
With this approach, we reduce the generation interval down to one or
two years and accelerated response to selection.
Our results show that it is no longer necessary to wait for
pure lines before evaluating genetic merit in cross progeny.
In addition, we have increased genetic diversity in the breeding program due to
higher effective population size through the use of optimal contribution selection.
We show that these advances would occur long into the future
at double the right of existing methods.
And in our models, the new methods achieved the FAO goal of
70% improvement in crop production by 2050.
Whereas, traditional breeding methods did not.
With the new animal model method in plants,
it is possible to make parallel improvements in disease resistance,
stress tolerance, and grain yield, and quality.
BLUP bleeding methods are based on a selection index, which combines all these
traits into one economic value, such as dollar value per hectare,
which is then used for selection of progeny for crossing.
On top of these new BLUP methods for breeding plants, we will overlay new
genomic selection technologies, and these will help to speed up the process.
Genomic selection has reduced generation interval and
improved efficiency of animal breeding.
New technologies will work more effectively in the new BLUP
breeding methods compared with traditional methods of plant breeding.
Plant breeding is an important part of the solution for future farming in 2050.
To be a successful plant breeder in the 21st Century, you will need skills
ranging from molecular genetics through to quantitative genetics,
field trial experimentation, and data analysis.
But it's fun to see the results of your research on farms and
to get feedback from farmers who grow your crop varieties.
You can help make farming more sustainable into the future
through improved crop varieties.
In this talk, I have described a new plant breeding method
which is looking very promising in the field.
This is an exciting time to join plant breeding and
improve the future of farming in the 21st century.
[MUSIC]
