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INTERVIEW
WITH
DR.ERNA
BENNETT
GENETIC
RESOURCES
EXPERT
A
(!
the modern varieties of
crops on whtch man depends
for food vulnerable to sud–
den, catastrophic cpidemics? To
flnd ou t.
Plain Trlllh
corres ponden!
Ray Kosanke of our Brussels Bu–
n::au ta lked with Dr. Erna Bennetl. a
U.N. expert on gcnetic conservation
and resources.
KOSANKE: Much publicity has
been given recently to the fact
that the profuse varieties of plant
life that man has used for cen–
turies to breed his food crops are
rapidly disappearing. What's
causing this genetic erosion?
BENNETT:
To begin with. we
ought to r ealize that the process of
genetic erosion ts almost inevitably
bound up wi th t he process of agri–
cu ltura! improvement. Wherever
agricu lture is improvcd. the old
va rieties are replaced with new
ones. The old stuff that the farmers
have been growing in their own
fie lds year aner year for generations
and generarions has been replaced
by new seed from plant breeding
stations, from the agricu ltura! cred it
bank.s, and from the agricu ltura! ex–
tension programs. The long and the
short of it is that everywhere that
agricultura ! dcvelopment takes
place the old varieties disappear. lt's
a fairly direct relationship.
a.
Could you give sorne exam–
ples?
A.
Certainly. The genctic diversi ty
in flax. in the l940s in Turkey was
very considerable. but by the la te
1950s the diversity of flax had al–
most entirely disappeared from that
34
particular area. Moving over to
Greece. our own examinations there
have shown that in 1930 about 80%
of the whea t that was sown was in–
digcnous whea t - nativc varieties
sown from the surplus kcpt by the
farmer from the previous year's
erop. By 1960. this proportion had
fallen to about 10%, but today it is
falling to something almost negli–
gible. The story is rcpeated end–
less ly a lmost everywhcre.
a.
Why do you consider this ero–
sion of genetic materials such a
critica! problem?
A.
One of the th ings that we notice
when we travel in primitive parts of
the world where these modern vari–
eties don't occur a t a l! , or didn ' t oc–
cur at a ll until quite recen tly, is that
there is no crop ever completely free
of disease but there is no crop ever
completely devasta ted by disease.
Disease and variety live in a kind of
genetic balance with each other.
ow if we sta rt lo rely not just con–
tinent wide , but on an ín ter–
con tinental basis on single va rieties.
the da nge rs of intercontinental epi–
demics a re correspondingly grea ter.
The conclusion seems to me to be
unavoidable that we ncglect genetic
diversity at our own rísk.
a.
In the rnajor bread basket
areas of the world, such as the
United States and Canada, are
we getting into a dangerous situ–
ation by not having greater vari–
eties of seed grains available?
A.
We can definitely say that ob–
!>Crvcrs from many o f thc Near East–
crn countries into which the high–
yicld ing, disease-resistant whe .... ats
have been introduced in the last
dccade are coming back now with
reports of wide-spread rust in–
fcctions, though not yet of epidemic
proportions. But we don 't know
what will happen in the future.
a.
What about the U.S. corn
blight in 1970?
A.
Here again is why wc are so con–
cerned a bout what is called genetic
vu lnerabili ty. In the case of maize,
you have an extremely narrow. ex–
tremely weak basis of resistance
relying on one or severa! genes at
th e very most which are very, very
"'
¡:
qui ckly bypassed by the pathogen.
a.
What do you think are the ma–
jor problerns in collecting native
seed specirnens?
A.
The problem basica lly is to go
out and get the material. Clearly,
th e less developed an area is, the
less a
zone
has been touched by
modern conditions, thc more impor–
tan! it is. Clearly, therefore, the ex–
plorer must aim to get away from
evcry sign of progress.
a.
How long can the seeds for all
of these different varieties be
maintained?
A.
That's a good question to which
there simply isn 't an answer yet, the
reason being that s tudies of seed
longevny are only now beginning to
be conducted in a precise and reli–
able way.
The combinations of temperature
and humidity a nd their effcct on the
viability of seeds of different species
are only now being examined for
the first time in a thoroughly me–
thodical manner, so obviously it's
going
to
be a long time before we
know the results.
lt looks as if certa in species can be
kcpt for severa! hundred years.
Others, fruit seed, for example, keep
very badly for only severa! months
or less than ayear.
a.
Sorne experts have suggested
it rnay already
be
too late to save
the rnajorityof theprirnitive strains.
ls this assessrnent accurate?
A.
Therc are many that have al–
rcady been extinguishcd. and we'l l
nevcr know how many. ln other
won.ls. when we make the final
count. it will merely be the count of
what we ha ve managed to save from
CXI111Ction.
The PLAIN TRUTH June 1976