Relation Between Rust (Uromyces viciae-fabae) and Faba Bean (Vicia Faba) Yield Loss in Bale Highlands, South Eastern Ethiopia

Abstract

In Ethiopia, Uromyces viciae-fabae is one of the most destructive biotic constraints for faba bean production. Information on the management and yield losses are inadequate in the Bale highlands where the crop is largely produced. The objective of this study was to manage faba bean rust through host resistance and fungicides, and determine the extent of yield losses. Field experiments were conducted at Madda Walabu University (MWU) and Harewa research stations. Four fungicides (mancozeb, fungozeb, nativo and diprocon) were used against four varieties having different level of resistance arranged in a randomized complete block design in a factorial combination with three replications. Data were collected on disease severity and yield components. Fungozeb sprayed at 2.5 kg a.i./ha proved the best management option in all varieties at both locations. Fungozeb foliar sprays reduced relative seed yield loss compared with their respective unsprayed checks. Generally, relative yield loss up to 56% at Madda Walabu University and up to 34% at Harewa from local unsprayed plots was recorded. Linear regression of the estimates indicated that -0.015, -0.051, -0.048 and -0.061 t/ha yield loss were predicted on walki, shallo, hachalu and local, respectively for every % days increase of area under disease progress curve (AUDPC) at MWU. Similarly, -0.123 t/ha on walki, -0.142 t/ha on shallo, -0.137 t/ha on hachalu and -0.151 t/ha on local variety yield loss was predicted for every %-days increase of AUDPC at Harewa. Significance differences were recorded in pods per plant and days to maturity. The unsprayed plots had shorter days to maturity as compared to plots sprayed at both locations on all genotypes. In conclusion, integration of walki and hachalu with fungozeb sprays was found to be effective management option. Moreover, extensive studies are recommended for evaluation of management options at different locations with similar agro-ecologies to enhance high quality faba bean production in Ethiopia.

Keywords: AUDPC; Fungicides; Rust; Severity; Vicia faba; Yield loss