REPORT - Search CIMMYT repository

ciated with and a direct result of the aforementioned
inadequate practices is the heavy
weed population in the wheat crop. Weed
control on most farms is inadequate. Thirdly,
insufficient or no fertilizer is used on most
fields. A jUdicious use of nitrogen and phosphorous
to promote early vigorous growth can
greatly increase yields even at low moisture
levels. In some areas, research must find the
ways to make it possible to "grow" the nitrogen
by adopting effective sheep-grain rotations
similar to those in Australia. This should be
investigated. It would mean, however, that
the farmer would have to go into a mixed
farming operation.
Turkey can readily become self-sufficient
in wheat and in the process release some of
the land for other purposes. The Government
must take determined action to ensure availability
of fertilizer and agricultural chemicals
for the control of weeds and insects. Seed
production seems well advanced. Top priority
must be given to research in order to determine
how to best raise yields and minimize
crop losses.
ARGENTINA
For several years, the wheat program in
Argentina carried out by INTA, has had the
collaboration of the Ford Foundation and
CIMMYT.
During 1969, a large number of lines from
the cooperative breeding program were evaluated
in yield trials at Marcos Juarez, Pergamino,
parana, Balcarce and Bordenave. For the
third consecutive year a number of sister lines
from three crosses, namely (Sonora x Tezanos
Pintos Precoz-Nainari 60) cross II 18889;* Sonora
64 x Klein Rendidor cross II 19975, and
Sonora 64 x Knott 2** cross II 18892 were
among the most outstanding materials. Several
of the most promising of these lines are now
being considered for commercial release in
Argentina.
Two lines that are very promising in Argentina,
namely, Sonora x Klein Rendidor selections
II 19975-68Y-1Y-5Y-H, and II 19975-68Y­
1J-6Y-1J-8Y which were developed by selection
in alternate generations in Argentina and Mex-
• Sister to the Mexican variety Jaral 66.
•• Knott 2 = is a line developed from a double converging
Thatcher backcross developed by Dr. D. Knott of the
University of Saskatchewan.
ico, were also top yielders in Tunisia during
1969-70. Both of the lines are also resistant to
Septoria tritiei and mildew under Tunisian conditions.
The former of these two lines was included
in the Fifth International Spring Wheat
Yield Test last year and ranked fifth in overall
yield in different parts of the world, indicating
boht broad adaptation and yield stability. Both
of these lines are now being multiplied for
commercial release by the Tunisian program.
It has become apparent during the past
year that the selection pressures for resistance
to rusts, Septoria and mildew in Argentina, and
Tunisia and Morocco are similar. Data and materials
developed in one of these widely separated
areas is likely to be of value in the
other and vice versa.
Septoria Resistance
During the past year a moderately severe
epidemic of Septoria tritici developed in the
nursery plots of Balcarce, in southern Argentina,
and considerable number of lines with a
high degree of resistance to Septoria were
identified. Among the most promising newer
lines were:
1. "PATO" - (Tezanos Pinto Precoz-Sonora
64) x Nariiio Cross 11-21974-4R-4M-2R-OY (6
sister selections).
2. "PATO"/Sonora 64 - Purdue x Ciano­
Inia Cross 11-28268-3B-300b (18 sister lines).
3. CIANO 67-Penjamo 62 Cross 11-24287­
8B-1J-1 B-Ob-(300-308b).
4. Penjamo 62-Purdue/Sonora x Selkirk E
Andes Cross 11-24263-2B-23J-1 B-Ob-(300-311 b).
Green Bug Resistance
A severe infestation of greenbug (Schizaphis
sp.) developed for the second time within
the past three years across a vast portion of the
wheat producing area of Argentina. Although
no accurate figures are available on the losses
caused by this pest, it probably reduced the
harvest by a million tons.
The nursery plots at Pergamino were very
severely infested and provided an excellent
opportunity to evaluate the breeding materials
for resistance. Several thousand lines were
under test. All of the material was severely
attacked and damaged except for 18 sister
lines all from one cross. The leaves of the
lines from the cross Cheg-Gaboto x Jaral "s"/
Klein Rendidor x Sonora 64 cross II-M-1023­
6P-2B-9P-2B-1 P' (and 18 sister selections) all
remained green and functional until maturity,
whereas the leaves of all other lines in the
nursery were killed before the grain reached
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