REPORT - Search CIMMYT repository

yields 25 to 30 percent higher than the better
open-pollinated varieties of this type. Yields
have climbed steadily since then, first with the
incorporation of germ plasm from the variety
Tuxpan (Texas), next with a yellow Tuxpeiio
from Mexico, and finally with the introduction
of a number of Caribbean composites developed
by CIMMYT. Yield potential of the present
hybrids is more than double that of the
first hybrids. And, perhaps most important of
all, open-pollinated varieties have been developed
from the latest CIMMYT materials which
equal or better the yields of the hybrids.
In Argentina, it appears that the new composites
made up from mixtures of local flints,
Caribbean flints and corn belt dents, will raise
yield levels to new highs.
Striking advances have been made with
new germ plasm mixtures in Southern and
South East Asia and in Tropical Africa. Thailand
is expanding acreage in the lowland tropics
and production is increasing at the rate
of 100,000 tons per year. India has increased
production by 50 percent in the last five or
six years. Pakistan increased production by
30 percent last year.
On the African continent, East Africa recently
has become self-sufficient in corn production,
using highland varieties developed
from a combination of Kenya flat white with
varieties introduced from the highlands of
Ecuador and Costa Rica in a cooperative program
with CIMMYT. This combination raised
yield levels by 40 percent. In the East Africa
lowlands, varieties developed by CIMMYT for
Central America have shown themselves to be
well adapted and much superior in yield to
native materials.
In West Tropical Africa, the Tuxpeno varieties
and the Tuxpeno-Caribbean composite
derivatives are rapidly replacing all other varieties.
New high-yielding varieties are being developed
in Egypt through a cooperative program
with CIMMYT using a wide-base germ
plasm complex including the Tuxpeno types
of Northern Mexico. This breeding work is
the first step in a long range program for
doubling maize production in Egypt.
The tremendous advances made throughout
the tropics and sub-tropics in the production
of maize and wheat can be attributed for
the most part to a combination of three principal
factors: (1) the development and utilization
of high yielding disease resistant varieties;
(2) the development and use of a package of
improved agronomic practices including better
seeding rates and more adequate use of the
right kind of fertilizer, and (3) a favorable
relationship between the cost of the inputs
and the price the farmer receives for his
product.
With differences of 50 to 100 percent in
yield and profits between the new technology
and the old, adoption has spread very rapidly
among the commercial farmers. This is especially
true in regions under irrigation, or with
generally adequate and good rainfall distribution,
where risks tend to be lowest. With
controllable good moisture conditions, the extension
of the new science-based technology
has been almost "auto-catalytic" clearly demonstrating
that the acceleration of production
is not so much a question of changing a farmer's
old traditional methods, customs and attitudes,
but more a matter of giving him a
technological package with which he can make
a profit. The bigger the profit, the faster the
technology moves.
Without doubt, the basic technological
factors sparking the Green Revolution have
been the high-yielding, widely-adapted diseaseresistant,
fertilizer-responsive varieties. In
maize, this variety does not have to be a hybrid,
it could be a good open-pollinated variety
highly responsive to improved scientific production
techniques.
If the Green Revolution is to extend further,
the breeding programs must be reinforced.
There are many areas for which no improved
varieties are available as yet. Also, in areas
where improved varieties are being distributed,
new materials will be needed periodically to
combat the ever changing complex of diseases.
CIMMYT, therefore, will continue to focus major
attention on varietal development.
In order to meet expanding requirements,
the wheat breeding work has been highly
internationalized. CIMMYT breeders have gone
into partnership with national breeders throughout
the world in an attempt to develop varieties
needed for 50 million hectares grown in
Latin America, North Africa, Turkey, the Near
East, Afghanistan, India and Pakistan.
Climates, diseases and agronomic practices
vary immensely over this vast region. The
main regional cooperative substations for
breeding, production-oriented field research,
and demonstration programs, are located in
Argentina, Brazil, North Africa (with central
axis in Tunisia) Lebanon, Turkey, India and
Pakistan. A system of international nurseries
has been designed and put into operation
whereby thousands of segregating families,
lines and varieties are tested in about 50 different
environments every year. In this way
information on adaptation, yield, disease re-
8