Screening of Ethiopian faba bean (<i>Vicia faba L.</i>) accessions for resistance and yield parameters against faba bean gall disease (<i>Olpidium viciae</i>) under field conditions

Abstract

Faba bean (Vicia faba L.) has been produced for centuries in Ethiopia and provides protein supplements to the diet of rural households. It is recently threatened by a new emerging gall disease caused by the fungal pathogen Olpidium viciae Kusano. The purpose of this study was to screen faba bean accessions with high yield potential for resistance against gall disease under rain-fed field conditions. A local check and 180 accessions were screened following standardized procedures. The seeds were sown in a randomized complete block design with three replications during the 2017–2019 cropping seasons. SPSS statistical software version 20 was used to calculate the disease severity index (DSI), an area under disease progress curve. Significant (p0.05) positive correlation was recorded between the disease severity and altitude (r = 0.27), precipitation (r = 0.37). Though no accessions were found resistant, 87.18% were identified as moderately resistant (DSI: 16.50–39.45%) to the test pathogen. In a combined mean analysis over districts, the lowest DSI was recorded for FB-Obse (DSI=16.50%), FB-Hachalu (DSI = 17.83%), FB-26872 (DSI = 18.84%), FB-26873 (DSI = 9.61%), and FB-28107 (DSI = 19.85%) accessions. Similarly, they exhibited various levels of yield potentials. The highest DSI rate (74.88–100%) was recorded between 38–77 days after crop emergence. The average minimum infection rate was recorded (r = 0.003) for FB-26873 variety at Sululta with a coefficient of determination of 79.00%. Crops with the lowest DSI exhibited the uppermost yield parameters. Hence, faba bean accessions with the maximum yield and moderate resistance to gall disease were recommended to be used for production.