Septoria and Stagonospora Diseases of Cereals - CIMMYT ...

Session 6C — R.M. Gonzalez I., S. Rajaram, and M. van Ginkel
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an impressive final yield when
challenged by the fungus. In this
study BOW/MII//RES/NAC/3/
PFAU is an example of a line with
high yield potential, which despite
having 20% of its flag leaf area
damaged by Septoria/Stagonospora
spp., resulting in a 31% mean yield
loss, still yielded 14% more than
the commercial check.
The most desirable genotype is
one that combines high yield
potential with resistance/tolerance
to the fungus; this results in
relatively low losses in the presence
;
200
;;;
% yield of check Curinda
150
100
CC 1994
CC 1995
CC 1996
UP 1994
UP 1995
UP 1996
of disease, and outstanding yields
in its absence. The line IAS20/
H567.71/5*IAS 20 combines these
traits; only 18% of its foliage was
affected, which translated into a
minimal yield loss of 13% and
resulted in the trial’s top mean
yield of 3380 kg/ha, 26% over the
commercial check, Curinda, in the
presence of disease (Table 2 and
Figure 1). It produced a very
respectable yield of 4094 kg/ha, the
third highest of the group, in the
absence of disease. This line is now
being considered for release under
the name Patzcuaro.
References
Table 3. Correlation coefficients of flag leaf severity and yield with various other characters, Patzcuaro,
Michoacan, Mexico, during 1994, 1995, and 1996.
Eyal, Z., A.L. Scharen, M.D. Huffman,
and J.M. Prescott. 1985. Global
insights into virulence frequencies
of Mycosphaerella graminicola.
Phytopathology 75:1456-1462.
Gomez, B.L., and R.M. Gonzalez I.
1987. Mejoramiento genético de
trigos harineros para resistencia a
Septoria tritici en el área de
temporal húmedo en Mexico. In
Conferencia regional sobre la
septoriosis del trigo, M.M. Kohli
and L.T. van Beuningen, eds.
Mexico, D.F.: CIMMYT. pp 42-57.
Variables Variables 1994 1995 1996
Flag leaf severity due to infection Yield -0.81 -0.83 -0.71
by Septoria/Stagonospora Test weight -0.72 -0.34 -0.44
Plant height -0.48 -0.55 -0.62
Yield loss (%) 0.71 0.33 0.71
Days to flowering -0.42 -0.71 -0.84
Yield Test weight 0.72 0.85 0.76
Plant height 0.62 0.44 0.55
Yield loss (%) -0.75 -0.49 -0.86
Days to flowering 0.46 0.86 0.79
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50 Curinda Batan 3 4 5 6 7 8 9 10 11
Figure 1. Yield as percentage of the tolerant check Curinda, in chemically controlled plots (CC) and
unprotected plots (UP) of nine wheat lines, during 1994, 1995 and 1996. Patzcuaro, Michoacan, Mexico.