Characterization of Temporal Attribute of Turcicum Leaf Blight Epidemics of Maize at Ambo and Bako Districts

Abstract

Turcicum Leaf Blight (TLB) of maize which is caused by Exserohilum turcicum
(Pass.) Leonard and Suggs is a major foliar disease in Ethiopia causing yield loss in
the range of 13.6 to 56% depending upon the genotype. Field Experiments were
conducted for two consecutive years in two locations viz. Ambo and Bako
Agriculture Research Centers to study the temporal attributes of the disease. Six
parental lines which constituted tolerant (lineI), susceptible (Iine2), resistant
(Iine5) and three moderately resistant lines (lines 3, 4 and 6) selected from
highland maize screening tests were used for the experiments. A randomized
complete block design with three replications was used. In 2014, at Ambo, the
AUDPC and severity of lines I, 2 and 3 significantly varied from lines 4, 5 and 6
(P = 0.0008 and P = 0.0005, respectively). The apparent infection rate was not
significant among all the lines in the same year. However, there were no
significant variations in the AUDPC, severity and apparent infection rate of TLB
among the six lines in 2015. These parameters did not significantly vary in 2014
at Bako. TLB disease was explained by the Logistic model on maize lines land 4
in 2014 at Ambo while it was fitted by the Gompertz model on maize lines 2 and
3.TLB disease also explained by the monomolecular disease progress model on
lines 5 and 6. None of the models was able to effectively explain TLB disease
progress at Bako in 2014 and at Ambo in 2015. Additional studies involving more
maize lines and locations are recommended to adequately explain the epiphytotic
of the disease and to recommend resistant lines for breeding programs.