My name's Mark Tester, and I've been
asked to talk about the genetics
of abiotic stress tolerance.
I work primarily on
so the focus will be on that.
However, of course, I'll try to
allow people to think more broadly
and to consider how the work that
we're doing on salinity tolerance
could be applied to studies on
drought tolerance, low temperature
and all those other abiotic
stresses that impinge
on the plant's daily life.
The context for a lot of work on
abiotic stress tolerance of plants
is the requirement to
increase food production.
This increase is
required in ways that
are much greater than previously.
In this slide, there's an analysis
of the global cereal production
over the last 50 years, in blue,
and you can see that empirically,
it is observed to be linear,
with an average increase of
about 32 million tons a year.
If we are to meet the FAO's
requirement for an increased food
production of 70% by 2050, we need
to increase this annual increase,
if you're still with me,
from 32 million tons a year
to 44 million tons sustained
over the next 40 years.
That's increasing the rate of
annual increase of food production
that's been going 50 years by 38%.
This is a very, very tall order, and
requires significant innovations.
One of the areas in
which we need to innovate
is to increase yield
we'll discuss on the next slide.
So we need to increase
the food supply.
There are only modest
opportunities left to increase
the area under cultivation.
There's, I think, also only
a modest theoretical chance
to increase the yield potential.
That's a little more arguable,
but I think it's a generalization
that has a fair bit of validity.
What we need to be able to do is
increase what is termed the yield
the ability of plants
to maintain their growth under
relative to optimal conditions, so
increase their ability to maintain
yield when there is a
low supply of water,
a high amount of
salinity in the subsoil,
increasing the ability of plants
to use nitrogen more efficiently.
To do this, and to do this at a rate
described in the previous slide,
we need a serious innovation.
We need to use the tools of
plant science and agronomy.
We need to be able
to have innovation
in modern plant breeding, such as
provided by quantitative genetics
And we probably also need to use
the tools of genetic modification.
The graph on this slide shows three
different varieties of wheat grown
at different sites in
Australia from relatively well-
watered on the right
too much less well-
watered on the left of the slide,
and it's showing here
three different varieties.
The one in green is better able
to maintain its yield as you go
to lower water supply sites
compared to the other two varieties,
in particular the one in red, where
there's a big decrease in yield.
What we're wanting to do
is find the genes that
are in such as that green variety,
which are better able to help
the plant maintain growth
under the low water conditions
and thus contribute to what we
would term this yield stability.
My work mainly focus on salinity,
and this can be used
for this lecture
as a model for abiotic stress
tolerance and the use of genetics
to try to address
abiotic stress tolerance.
Salinity is actually quite
a good area of research
to choose because it is widespread.
It's present in semi-arid,
It's particularly widespread
in irrigated systems, where
globally, perhaps 20% of
the land area is affected,
and that area is increasing.
This is particular pertinent
given that approximately 1/3
of the calories produced
in crops are produced
in these unsustainable,
irrigated systems in which
salinity is a very important issue.
Of course, salinity
is also increasing
because of seawater
ingress in many otherwise
highly productive coastal areas.
The deltas of some of the world's
major rivers are examples of this.
The Mekong River is the picture
in the top right-hand slide,
showing abandoned rice fields
in the delta of the Mekong River
Salinity can be addressed by both
management, agronomic solutions,
but also genetics,
and genetics can be a significant
contributor in irrigated systems,
but in dryland systems, it's the
only option for trying to increase
yields in areas with high amounts
of subsoil salinity and no water
to try to move that
salinity out of the system.
Another reason salinity's
quite a good report
is because the tolerance mechanisms
which are slowly being elucidated
are probably going to
be largely universal.
Salinity tolerance genes discovered
in a dryland wheat system,
for example, may well be likely
to have some level of contribution
in a wide range of other areas
globally, irrigated rice,
irrigated wheat, and so on.
So I think a lot of the
mechanisms can be applied
over a wide part of the planet,
and this is in contrast
to many other stresses,
in particular, drought, where some
adaptations that will help plants
grow well under one
type of low water
can, in effect be deleterious,
detrimental, to growth
in another type of drought.
There's no such thing
as drought per se.
There's different types of droughts,
and sometimes, often, in fact,
these different types of droughts
require quite distinct
physiological adaptations to try
to help plants maintain growth.
So drought is much more
complex than salinity.
So benefits of investment
in salinity research
are quite likely to
be delivered globally.