Effect of Septoria Trtici Blotch (Septoria tritici) on Grain Yield and Yield Components of Bread Wheat

Abstract

Bread wheat (Triticum aestivum L.) is widely grown in most of the regions in Ethiopia, including Southern Nations Nationalities and Peoples Region (SNNPR). But, its bread production is affected by abiotic and biotic factors. Among biotic factors, Septoria tritici blotch (STB) caused by the ascomycete fungus Mycosphaerella graminicola (asexual stage: Septoria tritici) Septoria tritici is one of the important problems of wheat production in the country; including Haddiya-Kambata areas of SNNPR. It is characterized by necrotic lesions on leaves and stems that develop after infected cells collapse, and more prevalent during cool, wet weather. Field experiment was conducted at Hossana and Angecha in 2012 main cropping season to quantify the effect of this disease on yield and yield components of bread wheat varieties. Three different spray intervals of propiconazole (Tilt 250 EC) and one unsprayed plot for each of the three varieties (Alidoro, Galama and Gambo) were used to create different STB epidemic levels. Treatments were arranged in randomized complete block design (RCBD) with factorial arrangement in three replications. Severity on all leaves (i.e. the leaves except flag leaf) and on flag leaf was recorded independently. The result of the study showed that, grain yield loss of 41, 29 and 12% were recorded on susceptible variety; Gambo,, moderately susceptible variety; Galama, and moderately resistant variety; Alidoro, respectively. In addition, loss of 48% biomass, 36% kernels per spike and 46% spikes per meter square were incurred on natural epidemic plots of variety Gambo at Hossana. Loss on days to heading, days to maturity, plant height, spike length and number of tillers per meter square is statistically nonsignificant at (P≤0.05). In general, this diseased caused considerable loss on yield and yield components of all varieties under the study. Therefore, as it is potential wheat production problem, giving attention and developing all possible management strategy is very pertinent.

Keywords: wheat, Septoria tritice blotch, severity, yield loss