Abstract:
Bread wheat is one of the most important cereal crops grown in different parts of Ethiopia.
However, its average productivity in the country is low (3046 kg/ha) as compared to its
yield potential in the world (3500 kg/ha). One of the factors for the low productivity of bread
wheat is Septoria leaf blotch disease and this a serious problem in the study area. Therefore,
screening of wheat genotypes was conducted at Dabat, during the 2021 main cropping
season to screen host plant resistance against Septoria leaf blotch. The experimental field
was designed in a simple lattice design with 2 replications and 100 genotypes. Similarly, a
field experiment was carried out in Debark and Dabat districts of North Gondar during the
main cropping season of 2021 to investigate the effect of varieties and fungicides on wheat
yield and yield components and the intensity of septoria leaf blotch during the main
cropping season of 2021. At both experimental sites, a factorial combination of three types
of varieties (Alidoro, Ogolcho, and local) and four fungicides (Tilt 250 EC, Mancozeb 80%
WP, Bayleton 25%WP, and unsprayed) were tested in a randomized complete block design
with three replications. The study for screening of genotypes revealed that none of the
genotypes were immune. The majority (61%) of wheat genotypes were sustained infection
responses that ranged from highly resistant to moderately resistant and gave a better yield
(>50quintal ha
-1
). About 28% of the genotypes were moderately susceptible. The remaining
limited genotypes were within the range of susceptible. The analysis of the factorial
experiment revealed that there were significant differences among the varieties for
incidence, severity, AUDPC, disease progress rate, grain yield, and yield components at
both locations while the interaction effect of variety with fungicides was observed for yield
at Dabat. Variety Alidoro sprayed with Tilt 250 EC had lower intensity, AUDPC, progress
rate of the disease and yield loss, and high highest PDC, yield, and net profit with an
acceptable marginal rate of return at Dabat. On the other hand, at Debark, the variety
Alidoro had lower severity (in all assessment dates), AUDPC, disease progress rate, and
high yield as compared to other varieties but the interaction effects were insignificant.
Finally, it is concluded that using a moderately resistant variety for Debark and
supplementing it by Tilt 250 EC for Dabat were found effectively manage septoria leaf
blotch of bread wheat respectively. However, further research is needed under different
agro-ecologies for additional years for the development of disease resistance variety, to
determine the best-integrated management options, and to increase the production and
productivity of bread wheat in the country.